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  • 201
    Electronic Resource
    Electronic Resource
    Synthesis and Structural Characterization of Mixed-Ligand Oxorhenium(V) Complexes Containing Bidentate Dithioethers and Monothiolato Ligands (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1343-1347 
    Details
    ISSN: 0009-2940
    Keywords: Rhenium ; Technetium ; Radiop[pharmaceuticals ; Mixed-ligand complexes ; sulfur ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Neutral oxorhenium(V) complexes with dithioether ligands of the general formula [ReOX3(RS[CH2]2SR)], × = Cl, Br, R = nBu, Et, Bzl were synthesized. Ammonium perrhenate reacts in concentrated hydrochloric acid with dithiaalkanes (RS[CH2]2SR, R =nBu, Et, Bz) dissolved in glacial acetic acid to give octahedral complexes of the type [ReOCl3(RS[CH2]2SR)] (1a-c). In concentrated hydrobromic acid, nBu-S(Ch2)2S-nBu leads to the corresponding tribromo complexes (2). The X-ray structure of shows a distorted octahedron with facial coordination of the bromide ligands. The sulfur atoms are cis coordinated to the terminal oxygen. Dissolution o f1a (R = nBu) in methanol leads to the substitution of the chloride trans to the oxo ligand by a meth oxy group. The resultant complex [ReOCl2(MeO) (nBu-S[CHL2]2S-nBu)] (3) is stable and can be isolated from methanolic solution, but changes to the μ-oxo-bridged dirhenium complex μ-oxobis[dichloro(5,6-dithiadidodecane)oxorhenium(V)] (4) when dissolved in other organic solvents. 1a reacts with an excess of benzenethiol by substitution of two chlorides to give the mixed-ligand complex bis(benzenethiolate)chloro(5,8-dithiadodecane)oxorhenium(V) (5a). The related 4-methylbenzenethiolato complex 5b was synthesized starting from the μ-oxo complex 4. X-ray crystal structure determination of 5b shows the equatorial arrangement of the sulfur atoms. The trans position to the oxygen atom is occupied by a chloride ion.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300927
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  • 202
    Electronic Resource
    Electronic Resource
    Editorial (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. i 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301003
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  • 203
    Electronic Resource
    Electronic Resource
    Diastereoselectivity in the Reaction of RCH2C[CH2P (Ar)(Lr)]3 with Electrophiles: Enhancement of Diastereoselective Control by η3-Coordination in {RCH2C[CH2P(Ar)(Li)3}Mo(Co)3 (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1379-1392 
    Details
    ISSN: 0009-2940
    Keywords: Chiral tripod ligands ; Tripod Mo(CO)3 compounds ; Diastereoselective synthesis ; Separation of diastereomers ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Following a procedure developed for H3CC[CH2P(Ph)2]3 (1a) as the starting compound, various tripod ligands RCH2C[CH2P(Ar)2]3 (1) have been transformed into the trilithiotriphosphides RCH2C[CH2P(Ar)(Li)]3 with various electrophiles R′  -  Hal leads to the two diastereomers of RCH2C[CH2P-(Ar)(R)]3 (6) with an (RRR/SSS : RRS/SSR) ratio close to the statistical value of 1:3, except when Ar=Ph and R′=Bzl, where the RRS/SSR diastereomer is obtained almost exclusively. In contrast, the reaction of [RCH2C[CH2P(Ar)(Li)[3]-Mo(CO)3 (4) with electrophiles R′  -  Hal tends to favour the formation of the homochiral RRR/SSS diastereomers. The triphosphide coordination compounds 4 are available by two different routes: either the complexes (RCH2C[CH2P-(Ar)(H)]3Mo(CO)3, obtained from 2 and (CH3CN)3Mo(CO)3, are deprotonated by MeLi, or the trilithiotriphosphides RCH2C[CH2P(Ar)(Li)]3 are reacted with (CH3CN)3Mo(CO)3 to produce 4 in high yields. The ration in which the two diastereomeric forms of 5 are obtained depends on the nature of the electrophile: the greatest diastereomeric discrimination is obtained for Ar=Ph, R=Ph, R′=Bzl, where the homochiral relative to the RRS/SSR pair. Two-dimensional NMR spectra and simulations of one-dimensional spectra are used to ascertain the diastereomeric excess in each case. X-ray analyses of three compounds of type 5 (5d, Ar=Ph, R=H, R′=Ph, R′=Bzl) indicate the remarkable conformational stability of the tripod metal scaffolding, with the conformations observed for these three compounds in three different solid-state environments being closely similar, even with respect to the torsional arrangement of the phosphorus-bound benzyl groups.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301006
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  • 204
    Electronic Resource
    Electronic Resource
    Gold(1) Complexes of Ketiminophosphanes and -phosphane Sulfides (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1423-1426 
    Details
    ISSN: 0009-2940
    Keywords: Gold ; Gold(I) complexes ; (Imine)gold(I)complexes ; Ketiminophosphanes ; (Ketiminophosphane)gold(I) complexes ; Ketiminophosphane sulfides ; (Ketiminophosphanesulfide)gold(I) complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions of chloro(dimethyl sulfide)gold(I) with equivalent quantities of the ketiminophosphane diphenyl(diphenylmethyleneamino)phosphane (1a) or its sulfide (1aS) lead to high yields of stable, crystalline 1 : 1 complexes with AuCl units attached to the phosphorus and sulfur atom, respectively. Tris(diphenylmethyleneamino)phosphane (1c) gives the related complex (Ph2C=N)3PAuCl with the gold atom also selectively P-bound. Bis(diphenylmethyleneamino)phenyl-phosphane (1b) could not be used because of its limited stability. Single-crystal X-ray diffraction studies have shown that there is no auxiliary coordination of the metal center by the imino functions of the ligands. The geometry of the P/S—Au—Cl moieties deviates only very slightly from linearity. The angle at the sulfur atom in (Ph2C=N)Ph2PSAuCl is very small [94.30(3)°], but despite of the resulting rather open coordination there are no discernible intra- or intermolecular contacts in the lattice. Such contacts are also absent with (Ph2C=N)Ph2PAuCl and (Ph2C=N)3PAuCl owing to the bulk of the ligands. The 1 : 1 complexes do not react with an excess of (Me2S)AuCl. This finding, and the molecular structures of the 1 : 1 complexes, show very consistently that both phosphane and sulfide donors are far superior as ligands for gold(I) as compared to ketimine donor molecules.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301011
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  • 205
    Electronic Resource
    Electronic Resource
    Pyrazolate-Based Oligonuclear Copper and Silver Complexes with N/S Coordination SpheresDedicated to Prof. Dr. Gottfried Huttner on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1441-1447 
    Details
    ISSN: 0009-2940
    Keywords: Pyrazolate complexes ; Bridging ligands ; Copper ; Silver ; N,S-Donor Ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of pyrazole-based potential ligands bearing thioether substituents in 3- and 5-positions of the heterocycle was synthesized [3,5-bis(RSCH2)-pyzH R=Ph (1aH), PhCH2 (1bH), iPr (1cH), tBu (1dH)]. These ligands afford oligonuclear Cu1 and Ag1 coordination compounds [LCu]x (2a-c, L = 1a - c) and [LAg]x (3a-d, L = 1a-d), respectively. The single crystal X-ray analysis of 3c shows the presence of trimeric planar arrays of N,N′-bridging pyrazolates and linear coordinated silver ions, with each two of the trinuclear moieties being linked by two unsupported short intermolecular Ag…Ag contacts [3.041(1) Å]. Molecular-weight determinations for 2a (THF) and 3c (toluene) indicate that hexanuclear entities are preserved in solution. Starting from 1bH the CuII complex [(1b)2Cu2](BF4)2 (4) was synthesized. According to an X-ray crystal structure analysis it consists of dinuclear molecules with two bridging pyrazolates, distorted square planar N2S2 coordination spheres for Cu11 and an axially bridging tetrafluoroborate. Magnetic susceptibility data reveal an antiferromagnetic exchange (J = -206 cm-1) that is among the highest found for doubly pyrazolate bridged dicopper(II) complexes, which is rationalized on the basis of the rather symmetric dinuclear core of 4. The irreversibility of the electrochemical reduction and oxidation processes for the CuII and CuI compounds, respectively, is explained by the inability of the respective coordination framework to adapt to different geometric preferences.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301014
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  • 206
    Electronic Resource
    Electronic Resource
    Hydrocarbon-Bridged Metal Complexes, XLI. Addition of Aniline Tricarbonyl Chromium Complexes to the Cyclohexadienyl Ligand of (μ5-C6H7)M(CO)3+ (M = Fe, Ru)Dedicated to Professor Hanns-Peter Boehm on the occasion of his 70th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1475-1477 
    Details
    ISSN: 0009-2940
    Keywords: Iron ; Ruthenium ; Chromium ; Carbonyl complexes ; N-(2,4-Cyclohexadienyl)aniline ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The addition of aniline tricarbonyl chromium complexes (η6-C6H4(R)NHR1)Cr(CO)3 (R=H, CH3; R1=H, CH3) to [(n5-C6H7)M(CO)3]+ (M=Fe, Ru) gives the heterobimetallic ligand-bridged complexes (OC)3Cr(n6-C6H4(R)N(R1)C6H7-n4)M(CO)3. The structure of (OC)3Cr(n6-C6H4(CH3)N(H)-C6H7-n4)Ru(CO)3 has been determined by X-ray diffraction.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301019
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  • 207
    Electronic Resource
    Electronic Resource
    New Phosphorus Heterocycles by Rearrangement of a [1,4-Bis(trimethylsilyl) η8-cyclooctatetraene-1,3,5-triphospha-7-hafnanorbornadiene ComplexDedicated to Professor C. G Kreiter on the occasion o f his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1491-1494 
    Details
    ISSN: 0009-2940
    Keywords: Phosphorus heterocycles ; Phosphaalkynes ; Triphospha Dewar benzenes ; Triphosphacyclobutadiene ; 1,4-Bis(trimethylsilyl)-η8-cyclooctatrienehafnium complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [1,4-Bis(trimethylsilyl)-n8-cyclooctatetraene]-2, 4, 6-tri-tert-butyl-1, 3, 5-triphospha-7-hafnanorbornadiene (3) rearranges nearly quantitatively to the corresponding 3,5,6-tri-tert-butyl-1,2,4-triphospha-7-hafnanorbornadiene complex 5 upon heating at 70°C. Treatment of complex 5 with trimethylphosphane at 50°C induces the displacement of di-tert-butylacetylene to give the new (n4-triphosphacyclobutadiene)hafnium complex 7, the crystalstructure of which has been determined by X-ray analysis. From complex 5 3,5,6,-tri-tert-butyl-1,2,4-triphospha Dewar benzene (6) can be synthesized by a redox reaction with hexachloroethane.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301022
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  • 208
    Electronic Resource
    Electronic Resource
    Dirhenium Complexes with S2CPR3 Bridges Donating Four and Eight Electrons  -  X-ray Structures of [Re2(CO)8{μ-η1;η1-S2CPCy3}] and {Re2(CO)6{μ-η3;-S2CPCy3}] and [Re2(CO)6{μ-η2; η3-S2CPCy3}] (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1507-1511 
    Details
    ISSN: 0009-2940
    Keywords: 1,1-Dithiolate ; Rhenium ; Carbonyl complexes ; Bridging ligands ; Bimetallic complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of fac-[Re(CO)3(S2CPR3)Br] with [Rc(CO)5]- affords the dinuclear octacarbonyl compounds [Re2(CO)8(μ-S2CPR3)] (3a—b), which have been isolated and characterized by spectroscopic methods. An X-ray crystal-structure determination of the derivative 3a (R=Cy) shows that the S2CPCY3 ligand acts as an η1(S);η1(S′) bridge donating two electrons to each metal atom of a symmetrical (CO)4Re—Re(CO)4 unit. This unit is presumably formed through a concerted process involving carbonyl/sulfur exchange in the nonsymmetrical octacarbonyl (CO)3(S2CPR3)Re—Re(CO)5 generated after the coupling of the bromo derivative with the carbonyl anion. Complexes 3a—b can be obtained more directly by adding S2CPR3 to [Re2(CO)8(μ-H)(μ-CH=CHnBu)], which is formed by irradiation of Re2(CO)10 with 1-hexene. Hydride addition to the central carbon atom of the S2CPR3 ligand of 3a-b occurs with loss of PR3, to give the anion [Re2(CO)8(μ-S2CH)]- which may be isolated as a salt with the PPN+ cation. The octacarbonyl compounds 3a-b can be converted into hexacarbonyl complexes [Re2(CO)6(μ-S2CPR3)] (5a-b) by heating in toluene or octane at reflux temperature. According to an X-ray crystal-structure determination of the derivative 5a (R=Cy), the loss of one carbonyl ligand from each rhenium atom is accompanied by the rearrangement of the S2CPR3 ligand which changes its bonding mode from η1(S);η1(S′) donating four electrons to η3(S,C,S′);η2(S,S′) donating eight electrons.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301025
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  • 209
    Electronic Resource
    Electronic Resource
    Interactions in Molecular Crystals, 118. The Sodium(benzo-15-crown-5) Salt of 2, 6-Di(tert-butyl)-4-methylphenol, a Sodium Phenolate with an Extremely Short Na+…O- Distance: Structure and Density Functional Calculations (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1533-1537 
    Details
    ISSN: 0009-2940
    Keywords: 2,4,6-Trialkylphenol deprotonation ; Sodium/benzo-15-crown-5 solvation ; Crystal structure ; Density functional calculation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structure of crystals, isolated in low yield, from the attempted metallation of diphenylmethane in tetrahydrofuran solution containing benzo-15-crown-5 at a sodium metal mirror is determined, surprisingly, to be the sodium (benzo-15-crown) salt of 2,6-di(tert-butyl)-4-methylphenol, an antioxidative stabilizer to prevent ether peroxide formation. The structure of the solvent-shared contact ion pair (monoclinic P21/n, Z = 4, R1 = 0.06) proves a strong Na+…O- interaction at the extremely short distance of only 216 pm, a sixfold O-coordination of the Na+ cation in a pentagonal pyramid, and a hemispherical distortion of the crown ether. Density functional calculations at the B3LYP/6-31G* level, based on the structural data, reproduce, within a one-dimensional hypersurface approach, the rather short Na+…O- distance, and predict Mulliken charges of +0.32 for Na′ and -0.71 for 0-, as well as a considerable polarization of the trialkyl phenolate anion.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301029
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  • 210
    Electronic Resource
    Electronic Resource
    Palladacycles as Reactive IntermediatesDedicated to Prof. Dr. Dietrich Döpp on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1567-1578 
    Details
    ISSN: 0009-2940
    Keywords: Metallacycles ; Palladium catalysis ; Domino reactions ; Polycyclic ring systems ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Palladacycles are discussed as the key intermediates of some important preparative ring forming reactions; their reactivity depends strongly on the ring size. The existence of 5-membered palladacycles, and even 4-membered palladacycles, is now firmly established, whereas the knowledge of 6-membered and larger palladacycles is based mainly on mechanistic considerations. The role of 5-membered palladacycles as catalysts is described briefly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301104
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  • 211
    Electronic Resource
    Electronic Resource
    Olefin Carbonylation Catalysis with Cationic Palladium Complexes: Selectivity and Possible Intermediates (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1557-1565 
    Details
    ISSN: 0009-2940
    Keywords: Carbonylations ; Alkenes ; Palladium ; Asymmetric catalysis ; P and N ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Palladium complexes L2PdX2 containing various group Va ligands and weakly coordinating anions are active catalysts for the carbonylation of olefin substrates. These catalytic systems, though gaining significance in industry for the synthesis of polyketones, are normally characterised by a low chemoselectivity. This derives from the numerous possibilities for initiation and termination reactions which lead to different catalytic cycles and from facile multiple alternating insertion reactions of olefins and carbon monoxide. Based on experiments carried out under conditions of low selectivity and on previously published data, the factors involved in the control of the regio-, chemo- and stereoselectivity for those reactions are discussed, taking current ideas and model studies involving the above palladium complexes into consideration.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301103
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  • 212
    Electronic Resource
    Electronic Resource
    Dichlorogermylene-Alkyldichlorophosphane Reactions Revisited: Characterisation of Bis(trichlorogermyl)phosphanes, Trichlorogermyldiphosphanes, and Ge-P Heterocycles (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1611-1618 
    Details
    ISSN: 0009-2940
    Keywords: Alkyldichlorophosphanes ; Insertions ; Carbene homologues ; Germanium ; Phosphonium germanate(II) ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions of alkyldichlorophosphanes 1 (RPCl2; R = tert-butyl: 1a, R = isopropyl; 1b, R = 1-adamantyl: 1c) with the germanium dichloride dioxane complex were followed by 31P NMR. Depending on the organic substituents and the reaction conditions, mixtures of trichlorogermylphosphanes RP(GeCl3)2 4a-c, RPHGeCl3 5a-c, diphosphanes R(H)PP(H)GeCl3 6a-c, R(Cl)PP(H)GeCl3 7a, b cyclophosphanes, and Ge-P heterocycles such as triphosphadigermolanes (RP)3(GeCl2)2 8a, b and tetraphosphagermolane (RP)4)GeCl2 10b are formed. As a further unexpected byproduct of the reaction of 1a with GeCl2-dioxane, a small amount of tri-tert-butyl(trichlorogermyl)cyclotetraphosphane 9a was isolated. From the reaction of 1c with two equivalents of GeCl2-dioxane, separation from byproducts 5c and 6c by crystallisation furnished colourless crystals of 4c (R = 1-adamantyl) as the first pure organylbis(trichlorogermyl)phosphane. Surprisingly, the reaction of isoprophylphosphane with germanium tetrachloride, intended to prepare 5a, led to crystalline isopropylphosphonium trichlorogermanate(II) 11. The structures of molecular 4c and 9a and ionic 11 were determined by X-ray crystallography.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301109
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  • 213
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    Electronic Resource
    Synthesis and Structure of Trimethyllead Niobocene DihydrideDedicated to Professor Jörg Lorberth on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1629-1631 
    Details
    ISSN: 0009-2940
    Keywords: Lead ; Niobium ; Hydrides ; Group 5 ; Group 14 ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of niobocene trihydride [Cp2NbH3] with ClPbMe3 in the presence of amine affords the plumbido dihydride complex [Cp2NbH2(PbMe3)] (1). Compound 1 represents the first example of a stable complex with neighbouring hydride and terminal plumbyl substituents. The structure of this compound has been established by NMR and IR spectroscopy and confirmed by an X-ray structure analysis.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301112
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  • 214
    Electronic Resource
    Electronic Resource
    Chlorides and Acetylacetonates of Transition Metals as Catalysts for the Oxidation of 1-Indanol by Sodium Percarbonate (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1655-1658 
    Details
    ISSN: 0009-2940
    Keywords: Catalysis ; Oxidations ; Transition metals ; Sodium percarbonate ; 1, 2-Dichloroethane ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The screening of metal chlorides and metal acetylacetonates as catalysts for the oxidation of 1-indanol by sodium percarbonate (at reflux in 1,2-dichloroethane in the presence of small amounts of Adogen 464) has been carried out. The efficiency of the process depended on the nature of the transition metal and its oxidation state but, except for iron, was not greatly influenced by the nature of the ligands. Good conversions and yields have been obtained using PdCl2, RhCl3, RuCl3 and, particularly, MoO2(acac)2 as catalysts.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301116
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  • 215
    Electronic Resource
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    Contribution to the Chemistry of Boron, 240 . Studies on Benzo-1,3,2-diphosphaborolanes, Benzo-1,4,2,3-diphosphadiborinanes and Benzo-1,5,2,3,4-diphosphatriborepanesDedicated to my friend Prof. Dr. A. Meller on the occasion of his 65th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1677-1692 
    Details
    ISSN: 0009-2940
    Keywords: Benzo-1,3,2-diphosphaborolanes ; Benzo-1,3,2-diphosphaborolane dimmers ; Benzo-1,4,2,3-diphosphadiborinanes ; Rearrangement reaction ; Pentacarbonyl chromium complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of benzo- 1,3,3-diphosphaborolanes C6H4(PR)2BR' (R = H, iPr, SiMe3; R' = R2N, R) has been prepared by several routes and characterized by spectroscopic and - in part - by X-ray diffraction methods. They feature pyramidal P atoms with the substituents in antiperiplanar positions. The P atoms act as coordination sites for the (CO)5Cr fragment. In contrast to the R2N-bearing benzo-1,3,2-diphosphaborolanes, the derivative C6H4(PH)2BCMe3 (4f) dimerizes by additional B-P bond formation to produce a pentacyclic system (4f)2. - The reaction of C6H4(PHNa)2 with B2(NMe2)2Cl2 in THF/hexane yields the acyclic phosphanylborane Me2NB(PH-C6H4PH2)2 (15). However, if C6H4[P(iPr)Li]2 is allowed to react with B2(NMe2)2Cl2, the benzo-1,4,2,3-diphosphadiborinane 13 is obtained, together with its rearrangement product 2-bis(dimethylamino)borylbenzo-1,3,2-diphosphaborolane 14 which dimerizes to (14)2.  -  In contrast, the almost planar ring of the 2,3-dimesitylbenzo-1,4,2,3-diphosphadiborinane (16) possesses P and B atoms with a planar geometry. Short B-B and B-P bonds suggest that this new heterocycle can be regarded as a 6π electron system. Moreover, the benzo-1,5,2,3,4-diphosphatriborepane 18 forms readily forms readily from C6H4(PHNa)2 and Br(Me2N)B-B(N-Me2)-B(NMe2) Br to give a tub-shaped seven-membered C2B3P2 ring system with the P atoms in a pyramidal and the B atoms in a planar environment.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301120
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    Geminal di(hypersilyl) Compounds  -  the Synthesis and Structure of Bis[tris(trimethylsilyl)silyl]methanol (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1709-1714 
    Details
    ISSN: 0009-2940
    Keywords: Silicon ; Strained molecules ; Silanes, sterically congested ; Tris(trimethylsilyl) silanes ; Silenes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tris(trimethylsilyl)silyllithium (1) reacts with methyl formate in diethyl ether (molar ratio 2:1) to give 1,2-di(hypersilyl)- ethylene 13. The formation of 13 proceeds through the intermediates formyl tris(trimethylsilyl)silane (4) and lithium bis-[tris(trimethylsilyl)silyl]methoxide (5). In diethyl ether, the alkoxide 5 spontaneously eliminates lithium trimethylsilanolate thereby generating 1,1-bis(trimethylsilyl)-2-[tris(trimethylsilyl)silyl]silene (9), which undergoes a formal [2+2] cycloaddition with the carbonyl compound 4 to afford 13. This was verified by crossover experiments. In Pentane, the alkoxide 5 is moderately stable. Thus, the intermediate 5, prepared by reaction fo 1 with tert-butyl formate in pentane. was protonated with water to give the di(hypersilyl)methanol 6 in good yield. The structure of 6 in good yield. The structure of 6 was elucidated by an X-ray crystal structure analysis, which expectedly revealed tremendous distortions of the molecular skeleton. Thus, the spatial demand of the two extended hemispherical (Me3Si)3Si groups forces a widening of the Si-C-Si angle at the central sp3 carbon atom to a value of 135.5°.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19971301123
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    Compounds of Germanium and Tin, 22 - Reactions of a Silyene with a Germylene and a Stannylene: Formation of a Digermene with an Unusual Arrangement of the Substituents and of a Stannane (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1733-1737 
    Details
    ISSN: 0009-2940
    Keywords: Silicon ; Germanium ; Tin ; Carbene homologues ; Digermene ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of the diaminosilylene :Si(tBuNCH2CH2NtBu) (5) with the diaminogermylene :Ge(tBuNCH2CH2NtBu) is thought to proceed via a germasilene → silylgermylene rearrangement and dimerisation to furnish the (Z)-1,2-diamino-1,2-disilyldigermene (Z)-9. The X-ray structure analysis of (Z)-9 reveals a long Ge—Ge bond length of 245 pm and a large trans-bent angle of 42°. Air-oxidation of (Z)-9 takes place with retention of configuration at the germanium atoms to provide the corresponding substituted (Z)-2,4-digerma-1,3-dioxetane (Z)-10. Treatment of 5 with the stannylene :Sn[N(SiMe3)2)2 gives, as a final product, the hydridodisilylstannane 12. The structures of (Z)-10 and 12 were also determined by X-ray crystallography.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19971301205
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    A Novel Approach to the Synthesis of Endohedral Fullerenes as Demonstrated by Endohedral Barium Fullerenes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1761-1764 
    Details
    ISSN: 0009-2940
    Keywords: Endohedral ; Barium ; Fullerenes ; Dibarium fullerenes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new route to endohedral fullerenes involving the evaporation of carbon and a metal at different positions, i.e. at different temperatures, in a radio-frequency furnace is described. For the first time, endohedral barium fullerenes within the composition range Ba@C74 to Ba@C136 have been produced in high yields as compared to hollow fullerenes, and have been extracted with CS2. Ba@C60, and Ba@C70, are only soluble in CS2 following sublimation. Furthermore, the first nonlanthanoid dimetallo fullerenes ranging in composition from Ba2@C88 to Ba2@C116 have been obtained. All endohedral barium fullerenes were characterized by mass spectrometry. Properties such as sublimation behaviour, solubility, and sensitivity to air have been studied.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301209
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    N′,N′,N″,N″-Tetramethylguanidine-Substituted Phosphoryl Compounds as Ligands in Transition Metal Chemistry - Unusual Modes of CoordinationDedicated to Professor Roald Hoffmann on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1825-1832 
    Details
    ISSN: 0009-2940
    Keywords: N′, N′, N″, N′-Tetramethylguanidine ; Phosphoryl ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methyl- and tert-butylphosphonic bis(N′,N′,N″,N″-tetramethylguanidinide) 1 and 2 were allowed to react with various transition metal compounds. The resulting complexes were studied by IR spectroscopy, mass spectrometry and, in the case of 10, by NMR spectroscopy. In the case of the compounds 7-10 the metal was coordinated only via the imino nitrogen atoms of 2, (IR evidence). X-ray structure analyses were performed for [L1CoBr2]2 6, L2CuCl2 9, and L2PdCl2 10 (L1 = 1, L2 = 2). In 5 L1 acts as an N,O bridging ligand, leading to tetrahedral coordination at Co and eightmembered (-Co-O-P-N-)2 rings. In 6 coordination by L2 chelates the metal atom through two N atoms, leading to PN2M rings; the coordination geometry is distorted planar.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301219
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    Oxozirconium Methacrylate Clusters: Zr6(OH)4O4(OMc)12 and Zr4O2(OMc)12 (OMc = Methacrylate) (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 473-478 
    Details
    ISSN: 0009-2940
    Keywords: Clusters ; Zirconium ; Metal alkoxides ; Sol-gel processes ; Carboxylato complexes ; Oxo complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The crystalline oxozirconium methacrylate clusters Zr6(O-H)4O4(OMc)12 and Zr4O2(OMc)12 were obtained by reaction of Zr(OnPr)4 with an excess of methacrylic acid and analysed by X-ray diffraction. The oxide and hydroxide groups are in a μ3- bridging mode in both structures, and the methacrylate ligands are chelating or bridging. The zirconium atoms in Zr6(OH)4O4(OMc)12 form an octahedron the cluster having crystalographic C3v symmetry. Each metal atom is square-antiprismatically coordinated by eight oxygen atoms. In Zr4O2(OMc)12, the zirconium atoms have a distorted butterfly arrangement; their coordination geometry is square-antiprismatically coordinated by eight oxygen atomes. In Zr4O2)OMc)12, the zirconium atoms have a distorted butterfly arrangement; their coordination geometry is square-antiprismatic or capped octahedral.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300406
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    New Five- and Six-Coordinate Nitrosylosmium(0) and Nitrosylosmium(II) Complexes Prepared from the Stable 16-Elektron Species [OsCl(NO)(PR)(PR3)2]Dedicated to Professor Waldemar Adam on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 493-506 
    Details
    ISSN: 0009-2940
    Keywords: Osmium(0) complexes ; Nitrosyl complexes ; Oxidative addition reactions ; Alkynyl(hydrido)osmium complexes ; Diynyl(hydrido)osmium complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The coordinatively unsaturated starting materials trans-[OsCl(NO)PiPr3)2] (2) and trans- [(sCl(NO)(PiPr2Ph)2] (3), for which a new one-pot synthesis is reported, react with isocyanides, SO2 and O2 to give the corresponding 1:1 adducts [OsCl(NO)(L)(P)(PiPr2R)2) (4-7). The corresponding methyleneosmium complex [OsCl(NO)(=CH2)(PiPr3)2] (9), on treatment with SO2 and HCl, affords the six-coordinate osmium(II) compounds [OsCl(NO)(K2(C,O)-CH2S(O)O)()iPr3)2] (10) and [OsCl2(NO)(CH3(PiPr3)2]2] (11), respectively. The reactions of 2 and 3 with HCl, I2, CH3I, CH2=CHBr, R'CO2H, PhSH, CH3OH, PhCOSH, and R'CHO lead by oxidative addition to the corresponding octahedral osmium(II) complexes [OsCl-(NO)(X)(Y)(PiPr2R)2] (12-24). The initially formed compound [OsHCl(NO){SC(=O)Ph}(PiPr3)2] (20a) rearranges smoothly to the more stable S-bonded isomer [OsHCl(NO){OC(=S)Ph}(PiPr3)2] (20b). Alkynyl(hydrid)- and diynyl(hydrido)-osmium(II) complexes 20-31 and 34, 35 are obtained from 2 or 3 and HC≡CCO2/sb〉Me, propargylic alcohols HC≡CCPh-(R')OH or the diyne HC≡CC≡CCPh2OH. The compounds [OsHCl(NO)[C≡CCPh(R')OH)(PiPr3)2] (30, 31) react with aqueous HCl in benzene to give the η1-allenylosmium(II) derivatives [OsCl2(NO)(η1-CH=C=C(Ph)R'](PiPr3)2] (32, 33). [OsHCl(NO)(C≡CC≡CCPh2OH)(PiPR3)2] (34) has been characterized by X-ray structural analysis.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300409
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    Highly Substituted Cyclams: Stereoselective Synthesis and Coordination Properties (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 521-528 
    Details
    ISSN: 0009-2940
    Keywords: Macrocycles ; Hydrogenation ; Cyclam, binding constant ; N ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We report here a new synthetic route to highly-substituted tetraazamacrocycles. Raney nickel hydrogenation of macrocyclic phenylenediamine-acetylacetone condensation products gives cyclams in high yield with complexes all-cis stereoselectivity. The extensive C-substitution of the cyclam 2a changes its ligand properties markedly. The X-ray structure analyses of NiII, CuII, and ZnII complexes of 2a reveals a deviation of the metal ion coordination geometry from the usual square-planar arrangement. This may account for the differences in the redox properties of the NiII and CuII complexes of 2a leads to more positive oxidation and reduction potentials compared to the analogous unsubstituted cyclam complexes. While the binding constant between Zn(ClO4)2 and 2a is lower by a factor of 105 compared to cyclam, the subsequent binding of uridine to the zinc-cyclam complexes in methanol/water is slightly stronger in the case of 2a · Zn(ClO4)2].
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300412
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    Enantioselective Catalysis, XIVPart XIII: U. Nagel, H. G. Nedden, Chem Ber. 1997, 130,385-397.Asymmetric Grignard Cross-Coupling Reaction: An Investigation of the Factors Influencing Asymmetric Induction with a New Type of Pyrrolidinephosphane (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 535-542 
    Details
    ISSN: 0009-2940
    Keywords: Cross-coupling ; Grignard reactions ; Pyrrolidinephosphanes ; Asymmetric amplification ; Gas chromatography ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An investigation of the asymmetric synthesis of 3-phenyl-1-butene by the Grignard cross-coupling reaction is presented. The reaction is catalysed by nickel complexes of bisphosphane and 3-diphenylphosphanylpyrrolidine-type ligands. A comparison of the results obtained with our P,N monophosphane ligands with those obtained with the most effective known amino acid derived P,N ligands shows a similar enantioselectivity but an inverse sense of optical induction. An X-ray structural analysis of the 1-phenylethyl Grignard compound is reported. Quantitative analysis and the determination of enantiomeric composition of the catalytic samples is accomplished using a novel enantioselective GLC separation. Compared to the popular model reaction that uses a chloride-containing Grignard compound and vinyl bromide as starting compounds, we obtain improved enantioselectivities of P,N monophosphane catalysts by substituting vinyl bromide with vinyl chloride. With two of the new P,N ligands we find a nonlinear dependence of enantioselectivity on the enantiomeric purity of the ligands (asymmetric amplification). Catalytic results subject to such nonlinear effects show a dependence on the ligand to nickel ratio.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300414
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    Atropisomeric Binaphthalene-Core Phosphacyclic Derivatives in Coordination Chemistry and Homogeneous Catalysis (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 543-554 
    Details
    ISSN: 0009-2940
    Keywords: Phosphorus heterocycles ; Binaphthophosphole ; Atropisomerism ; Binaphthophosphepine ; Hydroformylations ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Binaphthophospholes and binaphthophosphepines have recently been synthesized. These are the first representatives of a new class of chiral ligands that include within the same structure an endocyclic phosphorus donor, a local C2 symmetry and an axially chiral core. In this review we discuss the synthesis, chemical behaviour and first applications in asymmetric catalysis of these novel derivatives.
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19971300503
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    Iminoacylcobalt Compounds as Starting Materials for the Synthesis of Alkynylcobalt Halfsandwiches and CobaltaheterocyclesDedicated to Professor Günter Schmid on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 565-570 
    Details
    ISSN: 0009-2940
    Keywords: Cobalt ; Cycloadditions ; Heterocycles ; Alkynyl complexes ; Cyclopentadienyl complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The iminoacylcobalt compound [C5H5Co(C(CH3)=NCH3)(PMe2Ph)] (3) reacts with propargylic acid ester HC=CCO2R (R = Me, Et) to give the alkynylcobalt halfsandwich-type complexes [C5H5Co(C(CH3)=NHCH3)(C=CCO2R)-(PMe2Ph)]I (5, 6). With HC=CCO2Me as the substrate, besides 6 (R = Me) the five-membered cobaltaheterocycle [C5H5Co{K2(N, C)-N(CH3)C(CH3)CHC(CO2Me)}(PMe2Ph)]I (7) is also obtained. The reactions of 3 and the analogous benzyl derivative 4 with terminal alkynes HC=CR' (R' = CH2OH, CMe2OH, [CH2]2OH, CH2OMe, H, Me, nBu, Ph) afford exclusively the heterocyclic complexes [C5H5Co(K2(N,C)-N(R)C(CH3CHCR')(PMe2Ph)]I (R = CH3, CH2Ph) (8-18) in 60-70% yield. The molecular structures of 5 (R = Et) and 16 (R = Me, R' = Ph) have been determined by X-ray crystallography.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19971300506
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    (EIZ)-Equilibria, 19 Part 18: Ref.[19].  -  [*I X-ray structural analyses. Dimeric α-Lithio-2,6-dimethylstyreneDedicated to Prof. Joseph Klein on the occasion of his 80th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 585-592 
    Details
    ISSN: 0009-2940
    Keywords: Aggregations ; Complex, tert-butyl methyl ether ; diastereotopomerization, (EIZ) ; NMR, coupling, constants, HH, CH, CLi ; NMR, Lithiation shifts ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Improved preparations of 2,6-dimethylstyrene (5) and its α-bromo derivative (10) are described. The Br/Li exchange reaction of 10 provides single crystals of the title compounds 11 or 12, which were characterized as disolvated dimers by X-ray analyses. A similar dimer persists in diethyl ether, tert-butyl methyl ether, and toluene at all accessible temperatures, with significant lithiation NMR shifts (relative to 5) partially due to charge delocalization from the sp2-carbanionic center. Some NMR coupling constants are typical of the dimeric aggregate. The configurational (E,Z) lability is quantified in toluene solution.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300509
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    Dinuclear Cobalt(II) Complexes of Pyrazole Ligands with Chelating Side ArmsDedicated to Prof. Dr. Walter Siebert on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 605-613 
    Details
    ISSN: 0009-2940
    Keywords: Pyrazolate complexes ; Dinuclear complexes ; Bridging ligands ; Cobalt ; Conformational analysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of pyrazole-based potential ligands bearing polydentate amine substituents in the 3- and 5-positions of the heterocycle has been synthesized [3,5-bis(R2NCH2)-pyzH R2N = Me2N(CH2)3NMe (2aH), [Me2N(CH2)3]2N (2bH), (Et2NCH2CH2)2N (2cH)]. Upon reaction with two equivalents of CoCl2 they form complexes LCo2Cl3 (3a-c; L = 2a-c, respectively) which are shown crystallographically to contain a dinuclear metal core bridged by both the pyrazolate unit and a chlorine atom, with each cobalt center carrying a further terminal chlorine atom. Two of the ligand side arms in 3b, c are dangling, thus leading to five-coordination of the cobalt(II) centers in all cases. Addition of two equivalents of NaBPh4 to solutions of 3b, c induced coordination of the formerly dangling side arms to the metal centers by substitution of the terminal chlorine atoms. The resulting compounds [LCo2Cl](BPh4)2 (4b, c, respectively) were characterized by X-ray structure analyses. They can be viewed as dinuclear linked versions of tran-type complexes [(tran = tris(aminoalkyl)amine] with distorted trigonal-bipyramidal coordination spheres around cobalt(II). Conformational analyses employing force-field calculations were carried out for 4b, c in order to rationalize the conformations observed in the solid state with regard to the accessible conformational space.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300511
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    Gold Coordination by 2-(Diphenylphosphanyl)aniline (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 647-650 
    Details
    ISSN: 0009-2940
    Keywords: Gold(I) coordination ; 2-(Diphenylphosphanyl)aniline ; Ambidentate P ; N ligands ; P Ligands ; Ligand effects ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of 2-(diphenylphosphanyl)aniline (1) with (tetrahydrothiophene)gold(I) chloride in the molar ratio 1:1 gives a stable molecular complex 2, in which the gold atom is bonded to the phosphorus atom. Reaction of two equivalents of ligand 1 with one equivalent of the salt [(tht)2Au]ClO4 results in the displacement of both thioether ligands, affording the ionic complex {[(2-NH2C6H4)PPh2]2Au}+ ClO-4 (3a), in which the metal center is exclusively P-coordinated. Treatment of [(tht)2Au]ClO4 with ligand 1 (1:1) affords the mixed P/S-coordinated complex 4, the structure of which has been confirmed by single-crystal X-ray diffraction. The reaction of ligand 1 with [(Ph3P)Au]+ BF-4 leads to a mixture of products which are components of an equilibrium between the unsymmetrical salt {[(2-NH2C6H4)PPh2]Au(PPh3)} BF-4 with the two symmetrical species 3b (the BF-4 analogue of 3a) and [(Ph3P)2Au]+ BF-4, With {[(Ph3P)Au]3O}+ BF-4 as the aurating agent, the ligand 1 (molar ratio 1:1) is converted into a polynuclear complex 7, which is tentatively assigned a structure with intimate aggregation of six gold atoms.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19971300516
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    Masthead (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300601
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    Monomeric Phosphanylgalanes  -  Synthesis and Structural Characterization (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 663-668 
    Details
    ISSN: 0009-2940
    Keywords: Phosphanylgallanes ; Gallium amino compounds ; P Ligands ; Gallium ; Ab initio calculations ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The monomeric phosphanylgallanes R2GaPR'R (R = tmp, Mes; R' = H, tBu; R' Mes, tBu), the diphosphanylgallane mesGa(PtBu2)2, and diphosphandiylbisgallane [tmp2GaP-(tBu)]2, have been synthesized from alkali metal phosphides and substituted gallium chlorides. Low-temperature NMR studies of the phosphanylgallanes reveal no barrier to rotation about the gallium-phosphorus bond. Analysis of the crystal structures of tmp2GaPtBu2 confirms the monomeric nature of these molecules. The gallium-phosphorus bond lengths are found to be 237.5, 233.5, 235.4 pm (averaged), and 242.3 pm, respectively, with all phosphorus atoms being pyramidally coordinated.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300519
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    Fully Chlorinated N-Silyl Amides of Titanium and Tungsten  -  Crystal Structure of Cl3SiNW(Cl3)N(SiCl3)2 (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 701-704 
    Details
    ISSN: 0009-2940
    Keywords: N-Silyl amides ; Precursor ; 14N-NMR ; Titanium ; Tungsten ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of hexachlorodisilazanyllithium (Cl3Si)2NLi (1), with TiCl4 leads selectively to the novel fully chlorinated amides (Cl3Si)2NTiCl3 (2) or [(Cl3Si)2N]2 TiCl2 (3), respectively, depending on the molar ratio of the starting materials. The analogous reaction of 1 with WCl6 yielded the amide imide Cl3SiN=W(Cl3)N(SiCl3)2 (5) by elimination of SiCl4. The relative amounts of the starting materials had no effect on the formation of 5. 14/15N- and 29Si-NMR data on the starting materials and products show significantly different effects, when compared with those of analogous N-trimethylsilyl derivatives, due to the lower energy of the electrons in the N—Si and N—M ß bonds. The crystal structure of 5 (triclinic, space group P1) was determined by X-ray structure analysis.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19971300605
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    Electroactive Protecting Groups and Reaction Units, 6.Part 5: See ref. [21] - Titanium Enolate Radical Cations in Solution: Generation, Characterization, and Their Reactions (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 771-777 
    Details
    ISSN: 0009-2940
    Keywords: Titanium enolate ; Cyclic voltammetry ; EPR spectroscopy ; Radical ion ; Mesolytic bond cleavage ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: For the first time titanium enolate radical cations were characterized in cyclic voltammetry experiments. Preparative one-electron oxidation of titanium enolates 1-3 led to the formation of benzofurans B1-B3 through mesolytic Ti-O bond fragmentation to α-carbonyl radical and a cationic titanocene(IV) species. With 1+·, the kinetics of the Ti-=O bond cleavage was investigated by fast scan cyclic voltammetry providing a first-order rate constant k1=850 ± 50 s-1 in acetonitrile at room temperature. The titanium enolate radical cations 1+·, 3+·, 4+· and 5%% were characterized by EPR spectroscopy, qualifying these species as electrophilic radicals. This feature can be exploited in C—C bond formation reactions such as the formal dimerization of 6 to 2,3-dimethyl-1,4-diphenylbuta-1,4-dione D6, which takes place on stage of the radical cation 6+·.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300616
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    Ligand- Substrate Communication in Group 4 Aminopyridinato Complexes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 789-794 
    Details
    ISSN: 0009-2940
    Keywords: Agostic interactions ; Ligand effects ; Titanium ; Zirconium ; Aminopyridinato ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tris(aminopyridinato) zirconium and ansa-aminopyridinato titanium complexes have been sythesized. The reaction of (TMS-APy)3-Zr-Cl (4-methyl-2-trimethylsilyl-aminopyridine=TMS-APy-H) with trimethylsilylbutadiynyl lithium generated in situ affords (TMS-APy)3—Zr—C≡C—C≡C—TMS (1). (TMS-apy)3-Zr-Me2 (2). Compound 2 shows an agostic interaction of the dimethylamido moiety. The reaction of Ti(NMe,2),4 with silox(Apy-H)21,3-di(4′-picolin-2′-yl-amino)-1,1,3,3-tetraisopropyldisiloxane=silox (APy-H)2] gives rise to silox(Apy)2-Ti-(NMe2)2-Ti-[NMe,2)2 (3). Complex 3 reacts with ε-caprolactam to form a caprolactamato complex (4). X-ray crystal structure analyses of 1, 2, 3 and 4 are reported. The complexes 1, 2, 3 and 4 may be considered to be strained donor-functionalized amido(metal) complexes due to the η2 binding mode of the ligand cores, TMS-APy and silox(APy)2, to meet the requirements of the ancillary coordinated substrates is observed. Thus, aminopyridinato complexes seem to be valuable model compounds for investigations of ligand-substrate communications in early transition metal chemistry.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19971300618
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    Masthead (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300701
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    1,3-Di-tert-butyl-2,2,4,4-tetrahalocyclodisilazanes - Synthesis, X-ray Crystal and Gas-Phase Structures (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 835-837 
    Details
    ISSN: 0009-2940
    Keywords: Cyclodisilazanes ; 1,3-Di-tert-butyl-2,2,4,4-tetrafluorocyclodisilazane ; 1,3-Di-tert-butyl-2,2,4,4-tetrachlorocyclodisilazane ; Structure elucidation ; Electron diffraction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The syntheses of 1,3-di-tert-butyl-2,2,4,4-tetrachlorocyclodisilazane (3) and of di-tert-butyl-2,2,4,4-tetrafluorocyclodisilazane (4) are reported. The X-ray crystal structure of 3 and the electron-diffraction gas-phase structure of 4 have been determined. Both cyclodisilazanes possess planar four-membered rings and nearly planar configurations at the nitrogen atoms. The Si-N bond lengths are 171.1(1) pm and 170.6(3) pm and the Si⃛Si transannular distances 245.0(1) and 241.3(13) pm in 3 and 4, respectively.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300704
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    Structure and Reactivity of the Metal Centers of Ribonucleotide Reductases (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 317-322 
    Details
    ISSN: 0009-2940
    Keywords: Ribonucleotide reductase ; Tyrosyl radical ; Adenosyl radical ; Glycyl radical ; Iron-sulfur cluster ; Cobalamin ; (S)-Adenosyl methionine ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The activation of the three classes of ribonucleotide reductases as free radical enzymes is reviewed. Class I uses O2 and a diferric μ-oxo center to generate a stable tyrosyl protein radical. Class II operates with adensoyl cobalamin as the precursor of a putative transient thiyl protein glycyl radical by the concerted forms an O2-sensitive protein glycyl radical by the concerted action of an iron-sulfur cluster and (S)-adensoyl methionine.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300303
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    Synthesis and Bonding in Hybrid Diborolyl/Boranyl and Thiaboranyl Triple-Decker Compounds - Electronic Contribution of Heteroborane Cluster Ligands in ComplexesDedicated to Professor Rolf Gleiter on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 329-334 
    Details
    ISSN: 0009-2940
    Keywords: Triple-decker complexes ; Cobalta-nido-decaborane ; Thiacobalta-closo-undecaborane ; Dithiacobalta-arachno-nonaborane ; Dithiacobalta-arachno-dodecaborane ; Boron ; Cobalt/ Sandwich complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The three-component reaction of [(η5-C5H5)Co(η5-(CEt)2(BEt)2CMe)]-, CoCl2 and B9H-14 (7) yields the triple-decker complex [(η5-C5H5)Co{μ,η5-(CEt)2(BEt)2CMe}-6-Co(B9H13)] (8) with a terminal B9H13 ligand contaning two cobalt-boron-bridging hydrogen atoms. Analogously, (6-H)-, CoCl2, and arachno-6-SB9H-12 (10) react to give the triple-decker [(η5-C5H5)Co{μ,η5-(CEt)2(BEt)2CMe}-1-Co-2-(SB9H9)] (11). The analogous reaction with the heteroboranyl anion arachno-6,8-S2B7H8- leads to the loss of one boron atom, forming the air-stable triple-decker complex [(η5- C5H5)Co{μ,η5-(CEt)2(BEt)2CMe}-7-Co-6,8-(S2B6H8)] (12). The X-ray structure determination shows that the dithiacobaltaborane fragment in 12 has an arachno cluster geometry. The three-component reaction of (6-H, CoCl2, and arachno-2,3-S2B9H10- yields the expected triple-decker [(η5-C5H5)Co{μ,η5-(CEt)2(BEt)CMe}Co-6,8-(S2B9H9)] (15), and surprisingly the sandwich complex (η5-C5H5)Co-6,8-(S2B9H9) (16). The constitutions of the new compounds are based on NMR and MS data. A rule is described regarding the electron donation of heteroboranyl cluster ligands in metal complexes.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19971300305
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    Self-Assembly of Copper(I) Halide Networks Containing Tetra- or Pentameric Ethylcycloarsoxane (C2H5AsO)n (m = 4,5) as a flexible Bridging Unit (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 371-376 
    Details
    ISSN: 0009-2940
    Keywords: Ethylcycloarsoxane ; Copper(I) halide complexes ; Layered structures ; Macrocyclic ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In complexes of ethylcycloarsoxane (C2H3AsO)n, the oligomer size n is influenced by the coordinated metal atom. Cyclic tetramers are observed in the porous sheet structures of ∞2[Cu2Br2{cyclo-(C2H5AsO)4}3] (1) and 2∞ [Cu3I3{cyclo-(C2H5As0)4)2] (2), prepared by the reaction of the appropriate copper(I) halide with (C2H5AsO)n in acetonitrile. Both complexes contain μ1κAs1:2κAs3-coordinated (C2H5AsO)4 ligands as molecular bridging units between individual copper(I) centres leading to large respectively 36- and 40-membered rings. An analogous bridging mode is found in the cyclic oligomers [cyclo-(ReBr(CO)3{μ-[cyclo-(C2H5AsO)}}4](3) formed by reacting {ReBr(CO)5] with (C2H5AsO)n in refluxing toluene. - In contrast both [(NH4){cyclo- (C2H5AsO)5}2][Ag(SCN)]2 (4) and 2∞[(Cs(cyclo-(C2H5-AsO)3]2} Cu2(μ-I)I2] (5) contain pentamers (C2H5AsO)5, which coordinate the NH+4 and Cs+ cations κ5O in a pentagonal antiprismatic fashion. In 5, prepared by self-assembly from CsI, CuI, and (C2H5AsO)n in acetonitrile, [Cs[cyclo-{C2H5AsO}5)2]+ sandwich cations are linked thorough μ-1κAs1:2κAs2-coordinated [Cu2l3]- units into polymeric chains. This coordination pattern reflects the unique ring size adaptability of the ambidentate (C2J5AsO)n ligand.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19971300311
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    Metallacyclodisiladiazanes of Titanium and zirconium; Synthesis, Structure and Polymerization Studies (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 399-404 
    Details
    ISSN: 0009-2940
    Keywords: Disilylamides ; Group 4 Complexes ; Polymerization ; Metallacycles ; Titanium ; Zirconium ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of metallacyclodisiladiazanes has been prepared. Lithiated (SiMe2NHtBu)2 (1) reacts with TiCl4 · 2 THF to give (SiMe2NtBu)2TiCl (4). Methylation or fluorination of 4 leads to (SiMe2NtBu)2TiMe2 (8) and (SiMe2MtBu)2TiF2 (9), respectively. The reaction of ZrCl4 · 2 THF with lithiated 1 or [SiMe2NH(4-FC6J4)]2 (2) yields (SiMe2NtBu)2ZrCl2 (5) and [SiMe2N(4-FC6H4)]ZrCl2 · THF (7), respectively. The lithiated ligand [SiMe2NH(2,6-iPr2C6H3)]2 (3) reacts with noncoordinated ZrCl4 to give [SiMe2N(2,6-iPr2C6H3)]2ZrCl2 (6). X-ray structural analysis of 9 showed it to be a fluorine-bridged dimer in the solid state. Compounds 4, 6, 8 and 9 were found to be catalysts for the polymerization of ethylene.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19971300314
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    “Potassium Potassates” Based on Dihydrotriazinide Ligands: Syntheses, Crystal Structures, and Comparison with Other Alkali Metal Dihydrotriazinide Compounds (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 621-631 
    Details
    ISSN: 0009-2940
    Keywords: Alkali metals ; ate compounds ; Dihydrotriazine ; Potassium ; N ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of dihydro-s-triazinidopotassium complexes have been synthesised and structurally characterised by X-ray diffraction. Two of them, the sesqui-pyridine solvate 2 and the mono-THF solvate 3, can be classified in formal terms as “potassium potassates” in conforming to the structural pattern established previously for the sesqui-THF solvate 1, the first reported ate of this type. Formally complex [(R2K)-] anions are linked to K+ cations in polymeric, zig-zag chain arrangements. Solvate 3 also possesses a unique RK coordination as a direct result of having fewer solvent ligands. DMSO analogue 4 deviates from this uniformity in adopting a centrosymmetric, dimeric (OK)2 ring structure featuring both terminal and bridging DMSO ligands. The dihydro-s-triazinidosodium tris(THF) solvate 5 is found to be a monomer. For comparative purposes, the metal-free, parent triazine molecule 6 has also been subjected to an X-ray crystallographic study: it displays a 1,2-dihydro ring setup as opposed to the 1,4-dihydro alternative existing in the metallo examples. Triazine 6 is also found to form a N-H…Br bridge in the dimeric structure of the lithium bromide bis (THF) solvate 7, a suspected hydrolysis product from the reaction of dihydro-s-triazinidolithium 8 and magnesium bromide bis(ether) adduct.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19971300513
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    Models for Vanadate-Dependent Haloperoxidases: Vanadium Complexes with O4N-Donor SetsDedicated to Prof. Dr. R. Nast on the occasion of his 85th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 651-657 
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    ISSN: 0009-2940
    Keywords: Vanadium ; Haloperoxidase ; Schiff bases ; Diethanolamine ; Water ligation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of vanadyl sulfate with the Schiff base H2L1 derived from o-vanillin and glycine leads to [VIVO(H2O)L1 (1), treatment of which with acetyl chloride affords cis-[VIVCl2L1] (2). Reaction of [VO(acac)2] with the Schiff base H2L2 derived from o-hydroxynaphthaldehyde and o-hydroxyaniline under aerobic conditions yields [{VVO(L2)}2μ-O] (3), which undergoes methanolysis in excess methanol to form [VVO(MeOH)(OMe)L2] (5a). Complex 5a is also obtained via [VVOCl(L2)] (4) and MeOH. On treatment of 3 with an equimolar amount of ethanol, [VVOCl(L2)] (4) and MeOH. On treatment of 3 with an equimolar amount of ethanol. [VVO(OEt)L2] (5b) is obtained. With the chiral tertiary bis(ethanol)amine (S)- or (R)-(HOCH2CH2)2NCH(Ph)Me, H2L3, [VO(acac)2] loses only one acetylacetonate (1-) ligand, and the complexes (S)- and (R)-[VVO(acac)L3] (6a) are formed. As is evident for the corresponding reaction with (HOCH2CH2)2NPh, H2L4, which affords [VVO(acac)L4 (6b), the substitution is a second-order process (rate constant 0.013 M-1 h-1). 5a…MeOH, 5b, (R)-6a, and (S)-6a have been structurally characterized by single crystal X-ray diffraction analysis. The molecular connectivities have also been established for 1-H2O. All of the structurally characterized complexes contain an O*O3N donor set (O* denotes a doubly-bonded oxo group) and thus model the coordination environment of the active site in vanadate-dependent haloperoxidases. This model character is particularly pronounced in 5b, the coordination geometry of which is half-way to trigonal-bipyramidal. 5a and 6a contain, in addition to the O*O3N set, a labile V-O or V-N bond, respectively, which may mimic substrate binding to the active centre. 6a is also of relevance to the enantioselective peroxide oxidation of sulfides to sulfoxides by catalyst systems containing vanadium and H2L3.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19971300517
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    The Biological and Medicinal Chemistry of Bismuth (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 669-681 
    Details
    ISSN: 0009-2940
    Keywords: Bismuth ; Metallodrugs ; Bioinorganic chemistry ; Chelates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bismuth compounds have been widely used in medicine for more than 200 years, and new bismuth-containing drugs are now being developed. However the biological chemistry of bismuth is poorly understood. We review here methods for the study of bismuth compounds, and use of Bi(III) in antiulcer, antibacterial, anti-HIV and radiotherapeutic agents is described. The chemistry of Bi(III) carboxylates and aminocarboxylates is dominated by intermolecular interactions which lead to polymeric structures. Bi(III) exhibits a highly variable coordination number and coordination geometry, and alkoxide ligands can induce a strong stereochemical “lone-pair effect”. Bi(III) can bind to both Zn(II) sites (e.g. metallothionein) and Fe(III) sites (e.g. transferrin) in proteins. Further work is needed to understand the relationship between the structures and dynamics of bismuth compounds and their bioactivity.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19971300602
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    Divalent Tin and Lead Compounds EX2 Acting as Bridging Ligands in [{(CO)5M}2EX2]2- (E = Sn, Pb; M = Cr, Mo, W): Preparation and PropertiesDedicated to Professor G. E. Herberich on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 687-699 
    Details
    ISSN: 0009-2940
    Keywords: Tin ; Lead ; 119Sn NMR ; Salt metathesis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of Na2[M2(CO) 10] (M = Cr, Mo, W) with SnHal2 (Hal = Cl, Br) is a well established procedure for the synthesis of anions of type A, [{(CO)5M)SnHal3]-. Conditions are described which, for the same type of procedure, result in the additional formation of dianions of type B, [{(CO)5M}2SnHal2]2-. Procedures for separating these two types of anions in the form of their stable [Ph4P]+ or [nBu4N]+ salts by appropriate salt metathesis are presented. The structures of theses species have been characterized by X-ray analysis of three salts containing type A anions and two salts containing type B anions. The reactivity of the type B salts containing the bulky cations [Ph4P]+ or [nBu4N]+, respectively, is remarkably low; the salts are, however, transformed into highly reactive sodium salts by further metathesis with Na[BPh4]. In such salts the halide substitutents are easily exchanged as shown by the synthesis of ]})CO(5Cr}2oxinato]- (4)- from [Na-(THF)x]2[{(CO)5Cr}2SnCl2] and sodium 8-oxoquinolate, Na[C9H6NO]. The structure of the anion, 4 is compared to the structure of [[(CO)5Cr)SnCl2· THF] and sodium 8-oxochinolate. The preparation of the dinuclear anions [{(CO)5Cr}2E(OOCCH3)2]2- (E = Sn, 2g; E = Pb, 3) is accomplished by the reaction of [Ph4P]2[Cr2(CO)10] with the corresponding acetates E(OOCCH3)2. While 2g and 3 are formal analogues of the type-B anions, their structures reveal an asymmetrical η2-coordination of the two acetato ligands, in each case ending up in a 4+2 coordination for the main group centres, instead of the four-coordination observed for [{(CO)5M}2SnHal2]2-, All compounds have been characterized by usual spetroscopic and analytical techniques. X-ray analyses have been performed for selected examples. 119Sn-NMR data are presented for all of the compounds which contain tin-centred ligands.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19971300604
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    (η6-Arene)ruthenium(II) Labeling of Amino Acids and Peptides with Aromatic Side-ChainsDedicated to Professor W. Beck on the occasion of his 65th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 981-988 
    Details
    ISSN: 0009-2940
    Keywords: Ruthenium ; Tyrosine ; Tryptophan ; Sandwich complexes ; Bioorganometallic chemistry ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bis(arene)ruthenium(II) complexes of the type [(η6-cymene)Ru(η6-aa)](CF3SO3)n (2-9) containing L-tyrosine and L-tryptophan derivatives may be prepared by treatment of [(η6-cymene)Ru({CH3)2CO}3](CF3SO3)2 with the appropriate bioligand in CH2Cl2, for fully protected compounds and CF3COOH for α-amino acids (aa) with unprotected amine or carboxylic acid groups. Whereas the tyrosine and tryptophan methyl ester complexes [(η6-cymene)Ru(η6-H2tyrOMe)](CF3SO3)3 (4) and [(η6-cymene)Ru(η6-H2trpOMe)](CF3-SO3)3 (8) contain trications with protonated amino functions, the remaining compounds all exhibit dications. The crystal structure analysis of [(η6-cymene)Ru(η6-HtyrOH)](CF3SO3)2 (5) confirms a marked distortion towards an η5-oxohexadienyl coordination with deprotonation of the aromatic side chain. Although facial isomers are formed in an effectively 1:1 ratio for all tryptophan derivatives fractional crystallization allowed an X-ray structural characterization of the β-isomer of [(η6-cymene)Ru(η6-ActrpOMe)](CF3SO3)2 (6). Chemospecific labeling of the tryptophan side chain was established for the mixed dipeptide phenylalanyltryptophan.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19971300728
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    Enantioselective Catalysis, XVPart XIV: Ref. Preparative and Structural Chemistry of Diastereomeric Derivatives of 3-Phosphanylpyrrolidine and Their Palladium(II) Complexes - Asymmetric Grignard Cross-Coupling Reaction (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 989-1006 
    Details
    ISSN: 0009-2940
    Keywords: Cross-Coupling ; Grignard reactions ; Nickel ; Pyrollidinephosphane ; Cooperative effects ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The preparation of both diastereomeric derivatives of 3-(diphenylphosphanyl) pyrrolidine with chiral (tetrahydrofuran-2-yl)methyl and [(N-neopentyl)pyrrolidin-2-yl]methyl groups as substituents on the pyrrolidine nitrogen atom and of (2S,4S)-1-benzyl-4-(diphenylphosphanyl)-2-(methoxymethyl) pyrrolidine is reported. [3S,P(RS)]-3-(phenylphosphanyl) pyrrolidine, bearing an additional chiral center on phosphorus, is the starting material for the preparation of phosphanes, in which one phenyl group of the PPh2 moiety is substituted by an 2-methoxyphenyl (=An) or 2,4,6-trimethoxyphenyl (=TMP) group. PdI2 complexes of these ligands were separated into diastereomers by chromatography on silica gel columns. The structural chemistry of these novel phosphane diastereomers and their PdI2 complexes is investigated by X-ray crystallography and NMR. At the P,N-coordinated palladium center displacement of an iodide anion is found for P,N,N′ ligands only. In the nickel complex catalysed cross-coupling reaction, yielding 3-phenyl-1-butene, we obtain the highest enantioselectivities in the case of simple 1-alkyl-3-(diphenylphosphanyl)pyrrolidine ligands. The enantioselectivity obtained with diastereomeric derivatives, bearing additional ether or amine ligating sites is mainly determined by the chiral center in 3-position of the 3-(phosphanyl) pyrrolidine part of these ligands. Optimisation of enantioselectivity with these ligands can be carried out by a variation of the ligand to nickel ratio and by the choice of the vinyl halide used as starting compound. The catalytic cycle must contain at least one catalytically active species, bearing more than one β aminoalkylphosphane ligand.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300729
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    The Reactivity of Complexes of Nickel(0) and Platinum(0) Containing Benzyne and Related Small-Ring Alkynes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1029-1042 
    Details
    ISSN: 0009-2940
    Keywords: Nickel ; Platinum ; Aryne complexes ; Cyclohexyne complexes ; Insertions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The preparation and reactivities of cyclohexyne and aryne complexes of platinum(0) and nickel(0) are reviewed. These complexes undergo insertions with unsaturated molecules such as alkenes, alkynes, isocyanides, CO and CO2. In the case of the nickel- benzyne complexes, consecutive insertions are observed with alkynes, leading to substituted naphthalenes with good regioselectivities. A possible mechanism for these double insertions, based on a combination of steric and electronic factors, is discussed in detail.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300803
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    Synthesis and Structures of Sodium Phenylhydrazides (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1053-1062 
    Details
    ISSN: 0009-2940
    Keywords: Lithium ; Hydrazides ; Solvates ; Clusters ; Sodium ; Structure elucidation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Monomeric Li(Ph)N—N(Ph)SiMe3 · 2 OEt2 was obtained by deprotonating the respective hydrazine with nBuLi in the presence of diethyl ether. Reaction of NaN(SiMe3)2 with PhHN-N(SiMe3)2 in a benzene/tetrahydrofuran mixture provided monomeric Na(Ph)N—N(SiMe · 3 THF, or Nd(Ph)N—N(SiMe3)2 · THF using a small amount of THE Its TI IF ran be replaced by diethyl ether or tert-butyl methyl ether to give 1:l solvates. These associate, forming chains in the solid state via ηn coordination (n = 2, 3) of their phenyl groups to the sodium centers of adjacent molecules. In contrast, not only deprotonation but also desilylation occurs on reaction of NaN(SiMe3)2 with H(Ph)N—N(Ph)SiMe3 or of NaNH2 with (Me3Si)HN—NPh2) The latter reaction results in the formation ot hexameric (NaHN—NPh2)6 which adopts a face-sharing double-cubane structure.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300806
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  • 248
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    Characteristic Features of Neutral Cyclopropenylium-Like Compounds: Synthesis, Structure, and Chemical Behavior of a Cyclopropenylioborate Betaine (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1079-1084 
    Details
    ISSN: 0009-2940
    Keywords: Cyclopropenylium compounds ; Methylenecyclopropenes ; Isonitrile insertion ; Methylenecyclobutenone imine derivatives ; Cyclopropenylioborate betaines ; C-C coupling ; Zirconium ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bis(propynyl)zirconocene was treated with B(C6F.5)3 and then with two equivalents of tert-butyl isocyanide to yield the organometallic three-membered ring product 8. Subsequent hydrolysis gives the substituted (2-iminioethylidene)cyclopropeneborate betaine system 9 that exhibits a pronounced cyclopropenylioborate betaine character. This follows from its characteristic structural features (X-ray crystal-structure analysis of the isomer cis-9) and its chemical features. Complex 9 undergoes a very facile cis/trans isomerization by formal rotation around the exocyclic partial CC-double bond (ΔG+ ≈ 17 kcal mol-1). Compound 9 reacts cleanly in methanol solution with tert-butyl isocyanide by insertion and ring enlargement to form the four-membered ring system 12. Compound 12 was also characterized by X-ray diffraction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300809
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  • 249
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    Chiral Metal Carbene Modified [2.2]Metacyclophanes: Synthesis, Structure, and Chiroptic Properties (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1105-1111 
    Details
    ISSN: 0009-2940
    Keywords: Carbene complexes ; Chromium ; Cyclophanes ; Chirality ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pentacarbonyl(4-[2.2]metacyclophanyl(methoxy)carbene)-chromium(0) (6) was prepared according to the Fischer route from 4-bromo[2.2]metacyclophane. Aminolysis with non-chiral and chiral amines affords aminocarbene complexes 7-12. X-Ray structure analyses for 6 and its aminocarbene analogs 7 and 8 indicate that the incorporation of the chromium-carbene fragment has no significant influence on the deformation of the [2.2]metacyclophane skeleton.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300812
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    The Role of the 2,4,6-Tris(trifluoromethyl)phenylamino Group in Stabilizing New Phosphorus-, Arsenic-, and Germanium-Containing Main-Group Compounds and Transition-Metal Derivatives (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1113-1121 
    Details
    ISSN: 0009-2940
    Keywords: Phosphorus ; Arsenic ; Germanium ; Inorganic heterocycles ; Metal amides ; Fluorinated ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions of potassium Rf-amide [Rf = tris(trifluoromethyl)phenyl](2) with PCl3, AsC13, and GeC12 · dioxane yield new four-membered inorganic heterocycles [RfNPCl]2 (3), [RfNAsC1]2 (4), and [RfNGe]2 (5), respectively. On the other hand, the reaction of Rf-amide 2 with two equivalents of RfPCl2 leads to the formation of the imino-γ3-phosphane RfN=PRf (6) and the diamino-γ3-phosphane (RfNH)2PRf (7). The iminophosphane 6 reacts with Ni(CO)2(PPh3)2 and forms the complex [Ni(PPh3)2(RfN=PRf)] (9), in which the imino- phosphane coordinates to the metal through the phosphorus lone pair. Treatment of lithium amide 2 with transition metal chlorides ZnCl2 and FeCl2 yields the imido/amido spirocyclic metal derivatives 9 and 10, respectively. Compounds 3-10 have been extensively characterized by their analytical and mass, IR, and NMR (1H, 19F, and 31P) spectroscopy. Further, the molecular structures of all the compounds have been unambiguously determined by single-crystal X-ray diffraction studies. The diazadigermetidine 5 crystallizes in a fluorescent-yellow orthorhombic and a yellow monoclinic crystal modification. The results obtained reveal the role of Rf, group in stabilizing new multiple bonded systems and inorganic heterocycles. A skeletal rearrangment of the Rf ligand is observed in the reactions leading to compounds 9 and 10. Moreover, the preparation of compounds 9 and 10 indicates the limitation of the use of this ligand in the preparation of new metal-amide systems, especially where the metal atoms have a strong tendency for the formation of strong M—F bonds.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300813
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    Thio-Ligation to Vanadium: The NSSN and S′N′O Donor Sets (N = Pyridine, N′ = Enamine; S = Thioether, S′ = Thiolate) (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1129-1133 
    Details
    ISSN: 0009-2940
    Keywords: Vanadium ; S Ligands ; Schiff bases ; N ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The tetradentate, neutral disulfide [bis(thioether)] ligand 1,6-bis(o-pyridyl)-2,4-dithiahexane, NSSN, reacts with [VCI2(tmeda)2] to form the octahedral (all-cis; C2v-symmetric) complex [VCl2(NSSN)] 1, the first low-valent vanadium complex in which the thio functions are exclusively organic sulfides. Treatment of (VOCl2(thf)2] with O-mercaptoaniline, followed by reaction with o-hydroxynaphthaldehyde yields the non-oxo V′” complex [V(S′N′O)2] 2, derived from the Schiff base HS′N′OH, where 0 and S′ are phenolate and thiophenolate functions, respectively, and N′ is the Schiff base (enamine) nitrogen. Complex 2, with the ligands in a distorted trigonal-antiprismatic array, is a rare example of a structurally characterized complex where the Schiff base is preserved at the expense of its thiazoline tautomeric form.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300815
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    Masthead (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300901
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    A New Efficient Synthesis of the Stilbenoid Laser Dyes BPS and Stilbene I by Palladium-Catalyzed Coupling of Ethene with Bromoarenes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1193-1195 
    Details
    ISSN: 0009-2940
    Keywords: Stilbene ; 4.4′-Diarylstilbenes ; Palladium ; Pd-catalyzed ; C-C coupling ; Dyes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The palladium-catalyzed coupling of ethene with 4-bromobiphenyl and 4′-bromo-4-biphenylsulfonic acid permits a facile one-pot preparation of the laser dyes (E)-4,4′-diphenylstilbene (BPS, 3) and bis(triethylammonium) (E)-4,4′diphenylstilbene-4″,4″-disulfonate (6) in diastereomerically pure form on a multigram scale, with yields of 69 and 64%, repectively. The latter can easily be transformed to its dipotassium salt 7, the Stilbene I dye.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300905
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  • 254
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    Tellurium Polycations Stabilized by Halogenobismutates - Syntheses and Crystal Structure of te4[bi6Cl20] and te4[bi2br8] (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1189-1192 
    Details
    ISSN: 0009-2940
    Keywords: Tellurium ; Bismuth ; Tetratellurium(2+) ; Halogenobismutates(III) ; Crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of Te, TeX4 and BiX3 [X = Cl, Br] in sealed, evacuated glass ampoules in the temperature range 170° 100°C yields a variety of compounds composed of tellurium polycations and halobismutate anions. Two of these have been identified by crystal structure analyses as Te4[Bi6Cl20] (triclinic, P., a = 738.8(2), b = 875.1(2), c = 1389.1(6) pm, α = 87.89(2), β = 82.87(4), γ = 87.89(2) ·, Z = 1) and Te4[Bi2Nr8 (triclinic, P., a = 726.0(4), b = 773.7(4), c = 901.8(5) pm, α = 92.95(2), β = 102.23(2), γ = 92.87(2)., Z = 1). Both compounds were obtained as black crystals with a violet lustre and contain square-planar Te42+ cations. Te4[Bi6Cl20] contains a two-dimensional polymeric anion [Bi6Cl20]2- made up of corner- and edge-sharing BiCl6 octahedra with attached BiCl3 groups. The Bi-Cl distances vary over a very wide range from 245 to 334 pm. Te4[Bi2Br8] consists of a onedimensional chain [BiBr2Br4/2-[n of cis-edge-connected BiBr6 octahedra with Bi-Br distances ranging from 264 to 318 pm.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300904
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    Carbene Structure of Stable Acyl (Formyl) Anion EquivalentsDedicated tp Professor Dr. Peter Welzel on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1201-1212 
    Details
    ISSN: 0009-2940
    Keywords: Acyllithium equivalents ; Lithium ; Carbenes ; Structure elucidation ; Ab initio calculations ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 3-Lithiated 4-tert-butyl-imidazol-2-ylidene, 3-lithiated 4-tert-butyl-thiazol-2-ylidene, and the ZnBr species of the latter, are shown to be stable carbenes by X-ray crystal structure determination. The crystal data are confirmed by 13C-NMR investigations in solution and quantum-chemical calculations. The exceptional stability of the acyl anion equivalents is due to the p(.) stabilization of the carbene carbon atoms by the adjacent amino (thio) substituents, as is also the case in the structurally related stable carbenes, which have recently been isolated for the first time by A. J.Arduengo III et al., and in stable nitrenium ions, as found by our group.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300907
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    On the Polymorphism of White PhosphorusDedicated to Professor Gottfried Huttner on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1235-1240 
    Details
    ISSN: 0009-2940
    Keywords: Phosphorus ; Phase transitions ; Molecular crystal ; Crystal growth ; Low-temperature crystal structure ; Librational motion ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: White phosphorus occurs in three modifications. The α form, which exists at roomtemperature, transforms reversibly to the β form at -77°C. The α · β transformation may be strongly delayed. Quenching the α form to -185°C followed by slow warming results in an exothermic reactions with formation of the γ form which transforms into the β form at -120°C in an endothermic reaction. A transition β · γ is not observed. The γ form is characterized by its powder diagram. The structure of the β form is redetermined from a single crystal at -185°C (P., α = 547.88(5), b = 1078.62(11), c = 1096.16(11)pm, α= 94.285(8), β = 99.695(7), γ = 100.680(7)., V = 623.79(10) · 106 pm3, Z = 6 formula units per cell). The P4 molecules exhibit pronounced librational motion in spite of the low temperature of investigation. The arrangement of the centers of the tetrahedra corresponds to the atom positions in the γ-plutonium structure, which is discussed in relation to the bcc structure.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300911
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  • 257
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    Benzil Derivatives as Trapping Reagents for the Monomeric Alkylindium(i) Compound in-c(SiMe3)3 (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1269-1272 
    Details
    ISSN: 0009-2940
    Keywords: Indium ; Clusters ; Low-valent compounds ; Trapping reactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The tetrahedral cluster compound tetrakis[[Tris(trimethylsilyl)methyl]indium(I)] 91) reacts in boiling n-hexane with benzil derivatives (p-X-C6H4)C(O)(p-X-C6H4) (X = H, OMe, Br), to yield the 1,4-cycloadditon products of the monomeric alkylindium(I), In-C(SiMe3)3, in which the In atoms are coordinated by a chelating enediolato ligand, to form a five-membered InO2C2 heterocycle. As shown by two crystal structure determinations (X = H, OMe), the products are dimeric in the solid state, with a four-membered In2O2 heterocycle in the molecular center and both C(SiMe3)3 groups, as well as both enediolato substitutents in a cis arrangement.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300915
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    [CR(CO)5PCl3]  -  A Starting Material for Phosphorus-Rich Px Ligand ComplexesDedicated to Prof. Dr. Joachim Strähle on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1299-1304 
    Details
    ISSN: 0009-2940
    Keywords: P ligands ; P-P bond formation reaction ; Molybdenum ; Chromium ; Nickel ; Carbonyl complexes ; Main group elements ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [Cr(CO)5PCl3] reacts with different metallates K[CpxMo(CO)3] [Cpx = ·5-C5H4tBu (Cp]), ·5-C5H3tBu2-1,3 (Cp))], K[CpFe(CO)2], K[Cp]Cr(CO)3], K[C}*Ni(CO)] and Na2[Cr2(CO)10] at -78°C in THF to yiel various P2, cyclo- P3 and cyclo-P5 ligand complexes of the formulae [Cp] Mo(CO)2 (.2-P3)] (1a), [Cp]Mo(CO)2(.3-P3)] (1b), [{CP'Mo-(CO)2}2(μ,.2-P2)] (2a), [{Cp]Mo(CO)2}2(μ, ·2-P2)] (2b), [Cp]Fe).5-P5)] (3), [(Cp'Cr)2(μ,.5-P5)] (4), [{Cp]Cr(CO)2}2-(μ,.2-P2)] (5), [(Cp*Ni)2(μ,.2-P2){Cr(CO)5}2] (6). [{(CO)5Cr}Cl2PPCl2{Cr(CO)5}] (7) and [{Cr(CO)5}2PCl (8). Comprehensive studies of the reaction pathway leading to formation of the cyclo-P3 product 1a give strong indications that a sequence involving metal-halogen exchange and stepwise P-P bond formation takes place, proceeding via [{CO}5Cr}Cl2PPCl2{Cr(CO)5}] (7) and the cyclo-P3 precursor compond [{Cp]Mo(CO)3}{Cp'Mo(CO)2}2{Cr(CO)5}(μ,.3:1:1-P3)] (9). The latter two complexes have been isolated and structurally characterized.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300919
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    Chiral Arene Ruthenium Complexes, 2 A Diastereoselective Route to [η6-Benzyl Alcohol)(COD)Ru] Complexes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1321-1325 
    Details
    ISSN: 0009-2940
    Keywords: Arene Complexes ; Ruthenium ; Diastereoselective ; Reduction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two preparative routes are reported that give access to the racemic series of planar chiral [(arene)(COD)Ru] derivatives containing η6-bonded o-tolyl ketone or aldehyde arene units. The ketone and aldehyde functions of these have subsequently been reduced by nBuLi and PhLi, respectively. Hydrolysis converts the initially formed lithium salts into diastereomeric benzyl alcohol complexes lithium salts into diastereomeric benzyl alcohol complexes in high yields. The formation of the new stereogenic centre is diastereoselective (88% de) for the aldehyde and diastereospecific for the ketone (de 〉 99%). Due to a sterically overcrowded situation, the rotation of the chiral side chain of [(COD) (η6-o-tolyl-tert-butylphenylmethanol) Ru] (7) is hindered, as is the rotation of the phenyl and tert-butyl substituents. As a consequence, the hydroxyl group is fixed at a position close to the metal both in solution and in the solid state.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300923
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    Organo-Substituted 1,2-Dihydro-1,2,5-Disilaborepines (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1349-1352 
    Details
    ISSN: 0009-2940
    Keywords: Heterocycles ; 1,1-Organoboration ; Disilanes ; 1- Alkynylsilanes ; NMR spectroscopy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,2-Di-1-propynyl-tetramethyldisilan (1) reacts with triorganoboranes R3B [R = Et (2a), CH2Ph (2c), 2-thienyl (2d)], 9-ethyl-9-borabicyclo[3.3.1]nonane (3), and diethyl(N-pyrrolyl)borane (4) by twofold 1,1-organoboration to give selectively the respective organo-substituted 1,2-dihydro-1,2,5-disilaborepines 5a-d,6, and 7 in high yields. The compounds 5-7 were characterized by 1H-, 11B-, 13C-, and 29Si-NMR spectroscopy in solution. The molecular structures of the distance 1 and of the heterocycle 5c were determined by X-ray structure analysis.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300928
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    Complexes of Early Transition Metal Alkoxides: Molecular Structure of Ti(OiPr)4[OPb4(tBuN)3] (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1361-1363 
    Details
    ISSN: 0009-2940
    Keywords: Titanium ; Lead ; Alkoxides ; Amides ; Mixed-Metal species ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction between Ti(OiPr)4 and [Pb(NtBu)2] (1) in refluxing THF afforded the complex Ti(OiPr)4OPb4(NtBu)3] (2) which has been characterized by X-ray diffraction studies and by 1H- and 13C-NMR spectroscopy. Titanium is five coordinate and it displays a trigonal bipyramidal stereochemistry with the pb4(tBuN)3O cage ligand bonded to titanium through the oxygen atom and occupying an apical position. The origin of the cubane lead ligand is discussed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300930
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    Cobalt-Catalyzed Selective Oxidation of the Tritertiary Phosphane Triphos with Molecular OxygenDedicated to Professor H. Bärnighausen on the occasion of his 65th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1393-1403 
    Details
    ISSN: 0009-2940
    Keywords: Tripod ligands ; Phosphane oxides ; Cobalt ; Oxidation ; Catalysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactivity of complexes of triphos [CH3C(CH2PPh2)3] and CoCl2 towards dioxygen has been investigated. Reaction of the pseudo-tetrahedral complex (η2-triphos)CoCl2 (1) with dioxygen yields after work-up the mixed phosphane/phosphane oxide ligands triphosO and triphosO2. The novel ligand triphosO2 can be obtained in quantitative yield using catalytic amounts of 1. In order to gain some insight into the catalytic dioxygen activation reaction, experiments with various triphos/Co/Cl species, in different solvents and at several concentrations have been carried out. A mechanism involving two separate reaction pathways is proposed. Complexes of triphosO and triphosO2 with CoCl2, [η2-(P, P)-triphosO]CoCl2 (4), and [η2-(P, O)-triphosO2]CoCl2 (5), which are present as intermediates in the oxygenation reaction, have been isolated and fully characterized including X-ray structural analyses.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301007
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    Tetramethylguanidine and Benzophenoneimine as Ligands in Gold Chemistry (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1417-1422 
    Details
    ISSN: 0009-2940
    Keywords: Gold ; N ligands ; Gold(I) complexes ; (Imine)gold(I) complexes ; Guanidines ; Ketimines ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (Tetramethylguanidine)gold(I) chloride (1) and bromide (2) are readily prepared in high yield from (Me2N)2C=NH and [AuCl(Me2S)] or [AuBr(tht) (tht = tetrahydrothiophene), repectively. NMR spectra of chloroform solutions of the two products indicate equilibria of the type 2 LAuX = L2Au+AuX2-. The cationic complex [Au(NH=C(NMe2)2)(PPh3)]+ is obtained as the triflate salt 3 from tetramethylguanidine and [Au(PPh3)]+O3SCF3-. In solution at low temperature (-60°C), this compound adopts a rigid structure whereby the NMe2 groups are rendered non-equivalent, but at ambient temperature there is coalescence of the NMe2 signals in the 1H- and 13C-NMR spectra. The related benzophenoneimine complex [Au{NH=CPh2}(PPh3)]+BF4- (4), which was synthesized as a reference3 compound, exhibits similar behaviour. In solution at low temperature (-60°C) the two phenyl rings of the ligand are diastereotopic. In contrast, the triisopropylphosphane derivative [Au[NH=CPh2](PiPr3)]+BF4- (5) is rigid on the NMR time scale, even at 25°C. Thbe solid-state structures of 2, 3, 4, and 5 have been determined by single-crystal X-ray diffraction. Compound 2 crystallizes in the ionic form with discrete Au … Au bonded ion pairs [Au[NH=C(NMe2)2]2]+ [AuBr2]- [Au … Au 3.1413(8) Å]. The cations of 3, 4, and 5 show the [Au(PPh3)]+ units N-coordinated to the imino groups, with the nitrogen atoms in a trigonal-planar configuration.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301010
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    Reactive E=C [p-p] π Systems, 46Part 45: Ref. Syntheses and X-ray Crystal-Structure Analyses of Trifluoromethyl-Substituted Ketiminodiselanes, Selenoamides and SelenoacrylamidesDedicated to Professor Peter Sartori on the occasion of his 65th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 913-922 
    Details
    ISSN: 0009-2940
    Keywords: Selenium ; Fluorine ; Amides ; Cleavage reactions ; Cycloadditions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bis(trifluoromethylketiminoalkyl)diselanes [SeC(=NR)CF3]2 (6) [R = Me (a), iPr (b), tBu (c)] have been prepared in high yields (55-70%) by reaction of the diselane (SeC2F5)2 (2) with RNH2. However, the analogous reaction of 2 with secondary amines, R2NH, results in the cleavage of the Se-Se bond and leads to the N,N-dialkyl-2,2,2-trifluoroselenoacetamides Se=C(NR2)CF3 (7) [R = Me (a), iPr (b)]. Cleavage of 6a-6c with Me3SnH affords the selenoamides Se=C(NHR)CF3 (9) and the corresponding stannylselanes Me3SnSeC(=NR)CF3 (10) [R = Me(a), iPr (b), tBu (c)]. Selenoamides 7 and 9 can also be prepared from pentafluoroethylselenol HSeC2F5 (3), Se=C(F)CF3, (1) or its polymer [SeC(F)CF3]n (4) and primary or secondary amines. N,N-dialkyl-2-methyl-3-fluoro-4,4,4-trifluoroselenoacrylamides Se=C(NR2)C(Me)=C(F)CF3[R = Et (13a), iPr (13b)] are prepared in moderate yields under mild conditions by treating either trifluoromethylselenocarbonyl fluoride (1) or its polymer [SeC(F)CF3]n with 1-dialkylamino-1-propynes. The reaction proceeds by [2 + 2] cycloaddition and stereospecific electrocyclic ring-opening, yielding, with respect to the resulting C=C double bond, the E isomer as the only product. The molecular structures of 7b, 9a and 13b show the typical features of selenoamides with C(Se)-N bond shortening and C-Se bond elongation due to π interaction of the N lone pair with the C=Se double bond. The observed perpendicular orientation of the selenoamide and the alkene units of 13b prevents π delocalization.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300717
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    Contribution to the Chemistry of Boron, 238Part 237: See ref. Synthesis and Assembly Mechanism for Spirocyclic Cage Compounds Containing, B, P and Si Atoms (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 933-937 
    Details
    ISSN: 0009-2940
    Keywords: Boron ; Phosphorus ; Spiro compounds ; Cage compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of 1-lithio · DME-2,4-bis(dialkylamino)-l,3,2,4-diphosphadiboretanes (1a, 1b) with SiCl4 followed by dehydrohalogenation with tBuLi produce spirocyclic compounds [(R2NB)2P2]2Si (2a, 2b). The compounds have been characterized by spectroscopic methods and X-ray crystallography. The assembly process has also been followed and one intermediate species [(iPr2NB)2P2][(iPr2NB)P(H)(iPr2NB)P]SiCl (3) has been isolated and fully characterized.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19971300719
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    Photochemical Reactions of a Binuclear Naphthalene-Manganese Complex with 2-Butyne (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1197-1200 
    Details
    ISSN: 0009-2940
    Keywords: Binuclear complexes ; Manganese ; Napthalene complexes ; Dienyl complexes ; Alkynes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pentacarbonyl(μ-.4:6-1,4-dimethylnapthalene)dimanganese-(Mn-Mn) (1), upon UV irradiation at 193 K in the presence of 2-butyne (2), yields tetracarbonyl(μ-.2:2-2-butyne)(μ-1,2,3,4-.:1,4,4a,8a-.-1,4-dimethylnaphthalene)dimanganese (3) and tricarbonyl(4a,6,7,8,8a-.-5-hydro-1,4-dimethylnapthalene)-manganese (4). The tetracarbonyl complex 3 rearranges in solution at room temperature to give tetracarbonyl(μ-.2:2-2-butyne)(μ-4a,5,8,8a-.:5,6,7,8-.-1,4-dimethylnaphthalene)-dimanganese (5). The complexes 3 and 5 were characterised by IR and NMR spectroscopy, and by mass spectrometry, and complex 4 by IR and NMR spectroscopy. The molecular structures of 3 and 4 were determined by single-crystal X-ray diffraction analyses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300906
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    The Equilibrium Between 2-Lithium-Oxazole(-Thiazole, -Imidazole) Derivatives and Their Acyclic Isomers - A Structural InvestigationDedicated to Professor Dr. D. Seebach on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1213-1221 
    Details
    ISSN: 0009-2940
    Keywords: 2-Li(ZnCl)-substituted oxazoles (thiazoles, imidazoles) ; Acyclic isomers ; NMR spectroscopy ; Lithium ; Zinc ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2-Metallated oxazoles, thiazoles and imidazoles are of interest for the preparation of derivatives of the respective heterocycles, and - especially in the case of metallated thiazoles - as acyllithium equivalents in organic syntheses. Metallation at C2 of these compounds, however, often leads (more so with Li-oxazoles than with Li-thiazoles and Li-imidazoles) to products derived from the acyclic isomers of the metallated heterocycles. In order to obtain more information on the positions of the relevant equilibria, we have carried out a 13C-NMR study of substituted li- and ZnCl-oxazoles, Li-thiazoles and Li-imidazoles. In the case of Li-oxazoles, the equilibrium is completely on the side of the acyclic isomers. Addition of ZnCl2, however, leads to ring-closure, and, even in the case of 2-ZnCl-substituted benzoxazole, only the ring-closed isomer is observed. This demonstrates a dramatic gegenion effect on the equilibrium between two isomeric anions. In the case of Li-thiazoles, depending on the substitution pattern, either solely the ring-closed or an equilibrium with the ringopened isomer is observed. In the series of Li-imidazoles, only the 2-lithiated benzimidazole is in equilibrium with its ring-opened isomer. The tendency of these compounds to undergo ring-opening parallels the leaving group properties of the various subunits [OLi 〉 SLi 〉 R2NLi, and phenyl-O(S, NR)Li 〉 vinyl-O(S, NR)Li]. The difference between the effects of Li+ vs. ZnCl+ in the (benz)oxazole series is in agreement with results of solid-state structure investigations of 2-lithiated and a 2-zincated thiazole: in the Li compound the C-S bond is 2.9 pm longer than in the ZnCl species, indicating a more facile C-S bond cleavage with Li+ as the gegenion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300908
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    Masthead (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300801
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    Donor Complexes of Silylene, Germylene, and StannyleneDedicated to Professor Jürgen Hinze on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1013-1020 
    Details
    ISSN: 0009-2940
    Keywords: Donor-acceptor complexes ; Silylene ; Germylene ; Stannylene ; Ab initio calculations ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The complexes of various donor molecules, AH3 (A = N, P, As, Sb, Bi) and AH2 (A = 0, S, Se, Te) with silylene, germylene, and stannylene (1Al ground state) were studied by means of quantum chemical investigations at ab initio level utilizing all valence electron basis sets and relativistic corrected effective core potential methods. Accordingly, the donor molecules are weakly bound, the association energies are in the range of 15-30 kcal per mole. The exothermic energies for adduct formation, i.e., the resulting binding energies for the donor complexes, decrease in the order silylene 〉 germylene 〉 stannylene. The population analysis indicates for NH3 and BiH3 only a weak bonding towards the XH2 fragment (X =Si, Ge, Sn) while the higher homologues (A = P, As, Sb) form ylide structures, 1.2-dipolaric in nature. The addition of two donor molecules has been studied for silylene and is much less favourable than donor mono-addition. For the donor mono-addition a dual parameter relationship between (a) the HOMO energies of the donor (n-orbital of the AH3 unit, n, p-orbitals for AH2) and (b) the covalent bond energies (from the literature) versus the binding energies of the donor-acceptor compounds was examined. This dual parameter equation describes satisfactorily the essential features of the stabilities of the donor-acceptor structures.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19971300731
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    Flash Pyrolysis of 1,1,1-Trimethyltetrasilane - Evidence for the Formation of Dibridged Si2H2 (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1043-1046 
    Details
    ISSN: 0009-2940
    Keywords: Matrix isolation ; Ab initio calculations ; Oligosilanes ; Silicon atoms ; Reaction mechanisms ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pulsed flash pyrolysis of 1,1,l-trimethyltetrasilane (5) led to trimethylsilane, silane and a further species which is believed to be dibridged Si2H2 (13). Another route to 13 was found in the cocondensation of hydrogen and silicon atoms in an argon matrix at 12 K. The identification of matrix-isolated 13 is based on observed IR bands at 1475.6, 1092.8 and 890.3 cm-1. These positions are in good agreement with the ab initio calculated wavenumbers for the strongest absorptions of 13. The band shifts for the mono- and dideuterated isotopomers support this assignment.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19971300804
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    Synthetic Routes to Transition-Metal-Substituted Pentadiynylidene Complexes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1063-1067 
    Details
    ISSN: 0009-2940
    Keywords: Heterobimetallic complex ; Carbene complexes ; Bridging ligands ; Coupling reaction ; Alkynes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Sequential reaction of the dimethylamino(ethynyl)carbene complex [(CO)5 W=C(NMe2)C≡CH] (1) with nBuLi, CuI and BrC≡CSiMe3 affords the dimethylamino(trimethylsilylbutadiynyl)carbene [(CO)5W=C(NMe2)C≡C—C≡C—SiMe3] (2). Desilylation of 2 with KF/THF/MeOH gives [(CO)5W=C(NMe2)C≡C—C≡CH] (3). The C-stannylated carbene complex [(CO)5W=C(NMe2)C≡C—C≡CSnBu3] (4) is obtained by deprotonation of 3 with nBuLi and subsequent reaction with Bu3SnCl. Pd-catalyzed coupling of complex 4 with [ClRu(CO),Cp] affords the heterobimetallic pentadiynylidene complex [(CO)5W=C(NMe,)C≡C—C≡CRu-(CO)2Cp] (5) The analogous Fe derivative [(CO),W=C(NMe,)C≡C—C≡CFe(CO)2Cp] (6) is obtained by sequential reaction of 3 with nBuLi and [IFe(CO)2Cp] Similarly, treatment of 3 first with nBuLi and then with half an equivalent of HgCl2 affords the novel C4HgC4-bridged biscarbene complex [(CO)3W=C(NMe2)C≡C—C≡CHgC≡C—C≡CC(NMe2)=W(CO)5]( 7 ) All new compounds are stable at room temperature. Spectroscopic data suggest weak interaction of the metal centers in 5 - 7.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300807
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    On the Oxenoid Character of Alkylperoxy Anions and Their Lithium Compounds: A Combined Mass-Spectrometric and Theoretical Investigation (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1085-1097 
    Details
    ISSN: 0009-2940
    Keywords: Mass spectrometry ; Peroxides ; Oxenoids ; Density functional theory ; Kinetic energy release ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A combined mass-spectrometric and theoretical approach has been used for an investigation of the gas-phase chemistry of two representative alkylperoxy anions. Metastable CH3OO- ions undergo unimolecular loss of molecular hydrogen and formaldehyde yielding HCO-2 and OH-, respectively. The observed reactivity is in pleasing agreement with calculations of the [C,H3,O2- and [C,H,O2]- potential-energy surfaces at the BECKE3LYP/6-311+ + G** level of theory. Upon exhaustive methylation of the α-position as in t-C4H9OO- anions, the reactivity switches completely to an elimination of (CH3)2C=CH2 giving rise to the formation of HOO-. The results obtained for the “bare” alkylperoxy anions are used for the analysis of the EI mass spectrum of (t-C4H9OOLi)12 dodecamers, which thermally decompose in the inlet system at a probe temperature of ca. 130°C. The decomposition is rationalized by a mechanism involving nucleophilic attack of one t-C4H9OOLi subunit on the oxenoid oxygen atom of a second t-C4H9OOOLi moiety. This reaction may produce t-C4H9OOOLi trioxy species as intermediates, which rapidly decompose to singlet dioxygen and t-C4H9OLi.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300810
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    A New Route to Sila- and Phosphaheterocycles: Nucleophilic Aminomethylation (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1777-1785 
    Details
    ISSN: 0009-2940
    Keywords: Lithiation ; Aminomethylation ; Nitrogen heterocycles ; Diazasilaheterocycles ; Diazaphosphaheterocycles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The aminals tetramethylmethylenediamine (TMMDA) la, dicyclohexyldimethylmethylenediamine (CMMDA) lb, and di-isopropyldimethylmethylenediamine (IMMDA) lc are doubly metalated by LitBu to give LiCH2N(R)CH2N(R)CH2Li [2a: R = Me, 2b: R = Cy (Cy = cyclohexyl), 2c: R = iPr], which precipitate out of pentane as highly pyrophoric substances. Deuteration confirms N-methyl metalation exclusively. A series of aminomethylation reactions were performed by means of the doubly lithiated aminals 2a-c. The reactions of 2a-c with monochlorosilanes yield the silylated species R′3SiCH2MN(R)CH2N(R)CH2SiR′3 (3a: R′= Me, R == Me; 3b: R′ == Me, R == Cy; 3c: R′= Me, R = iPr 4: R′= Ph, R = Me, see Scheme 2). The use of dichlorosilanes lead to six-membered heterocycles 6a-6d. 6a is transferred into a mono quarternary ammonium salt 7 by methylation with MeI. The spirocycle 8 is obtained from SiCl4 and two equivalents of 2a. Similarly, several substituted 1,3-diaza-5-phosphacyclohexanes 9a-e (R1 = Me, Ph, NPh2, NCy2, see Scheme 3) are synthesized by the reaction of dichlorophosphanes R1PC2, with 2a and 2b, respectively. Oxidation of 9d with sulfur yields 12a, which is characterized by X-ray structure determination.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301212
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    Cyclic Diynes with Silicon in the Bridges: Structural and Photoelectron Spectroscopic Investigations (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1807-1811 
    Details
    ISSN: 0009-2940
    Keywords: Alkynes ; Photoelectronspectroscopy ; Electronic structure ; X-ray investigation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structures of 6-isopropylidene-1,1-dimethyl-1-silacyclodeca-3,8-diyne (2), 1,6-dimethyl-1,6-disilabicyclo[4.4.4]tetradeca-3,8,12-tryine (4), and 1,1,2,2,3,3-hexamethyl-1,2,3-trisilacyclodeca-4,9-diyne (6) have been investigated by means of X-ray crystallography. In 2 and 6 a chair conformation is adopted in the solid solid state. In 4 the three butyne groups are twisted around the Si—Si axis against one another. The torsion along the triple bond axis (Si-CH2-CH2,/Si) amounts to 29.0(1). The He(I) photoelectron (PE) spectra of 2 and 6 together with those of 1,1-dimethyl-1-silacyclodeca-3,8-diyne (1), 1,1,6,6-tetramethyl-1,6-disilacyclodeca-3,8-diyne (3),1,12,2,3,3-hexamethyl-1,2,3-trisilacycloundeca-4,10-diyne (7) have also been recorded. The PE spectra were interpreted on the basis of results from SCF MO calculations (3-21G*). They reveal a smaller splitting of the π-bands in 1-3 as compared to cyclodeca-1,6-diyne. In the PE spectra of 5-7 we encountered a strong interaction between the silicon chain and the in-plane π-orbitals.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19971301216
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    Linked Benzylamido-Cyclopentadienyl Ligands: Synthesis and Characterization of Alkyl Titanium Complexes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 209-215 
    Details
    ISSN: 0009-2940
    Keywords: Titanium ; Amidocyclopentadienyl ligand ; Alkyltitanium compounds ; Lewis acids ; Agostic interactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Titanium complexes of the general type Ti(η5:η1-C5H4Si-Me2NCH2C6H3X2-2,5)Cl2 (X=H, F), containing a linked benzylamido-cyclopentadienyl ligand, were prepared by reaction of Ti(η5-C5H4SiMe2Cl)Cl3 with lithium amide Li(NHCH2C6H3X2-2,5). A single-crystal X-ray structural analysis of Ti(η5: η1-C5H4SiME2NCH2C6H3F2-2,5)Cl2 revealed a conformation in the solid state in which the aryl ring is turned away from the metal center. Ti(η5:η1-C5H4SiMe2NCH2C6H5)Cl2 can be alkylated with a variety of reagents to form extremely sensitive complexes of the type Ti(η5-C5H4SiMe,2NCH2C6H5)R2 (R=Me, CH2 C6H5, CH2SiME3, CH2CMe2C6H5). Reaction of Li2[C5Me4SiMe2NCH2C6H5] with TiCl3(THF)3 gave Ti(η5: η1-C5Me4SiMe2NCH2C6H5)Cl2, which can also be alkylated to form dialkyl complexes of the type Ti(η5:η1-C5Me4SiMe2NCH2C6H5)R2(R=Me, CH2C6H5, CH2SiMe3, C6H5).A single-crystal X-ray structural analysis of Ti(η5:η1-C5Me4SiMe2NCH2C6H5)(CH2C6H5)2 suggests the presence of α-agostic bonding of one of the titanium-bound CH2C6H5 groups to the titanium center.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19971300211
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    Concave Reagents,22. Cyclopropanation of Alkenes with Ethyl Diazoacetate: Copper(I) Complexes of Concave 1,10-Phenanthrolines as Diastereoselective Catalysts (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 231-234 
    Details
    ISSN: 0009-2940
    Keywords: Diasteroselective cyclopropanation ; Copper compounds ; Homogeneous catalysis ; Molecular recognition ; Bimacrocycles ; Alkenes ; Macrocyclic ligands ; Heterocycles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Concave 1,10-phenanthrolines 1a-c have been used as ligands in the copper(I)-catalyzed cyclopropanation of alkenes 2 with ethyl diazoacetate. The complexes proved to be efficient cyclopropanation catalysts and exhibited an enhanced diastereoselectivity, particularly in the reactions of cyclic alkenes 2b-d. The preferred formation of exo-cyclopropanes 3b-d can be explained by the concave shape of these catalysts.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19971300215
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    Synthesis of Polycyclic Hydrocarbons by Palladium-Catalyzed Cross-Coupling Reactions of Vinylic Bromides with Diphenylacetylene (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 261-265 
    Details
    ISSN: 0009-2940
    Keywords: Polycycles ; Hydrocarbons ; Palladium catalysis ; Domino processes ; Cross coupling ; Homogeneous catalysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Vinylic bromides of type 1 undergo cross-coupling reactions with diphenylacetylene (5) leading to various polycyclic hydrocarbons. The ratio of the 1:1 to the 1:2 products can readily be controlled by varying the reaction conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300220
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  • 278
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    Silver Chloroacetate: Crystal Structure and Thermal Polymerization Mechanism (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 291-294 
    Details
    ISSN: 0009-2940
    Keywords: Halogenoacetates ; Silver salts ; Solid-state reactions ; Polymerization ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structure of silver chloroacetate was determined by single-crystal X-ray structure analysis. This represents the first salt of a monohalogenoacetic acid with a monovalent metal whose structure was determined with high precision. The salt undergoes a thermally induced solid-state polymerization to polyglycolide under elimination of silver chloride. A probable mechanism for a structure-determined reaction in the solid state is discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300224
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  • 279
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    Preparation of Methyl 2-[Bis(trimethylsiloxy)phosphoryl]-3,3,3-trifluoro-2- (trimethylsiloxy)propionate and Some Derivatives-Molecular Structure of Methyl 2-[Bis(trimethylsiloxy)phosphoryl]-3,3,3-trifluoro-2-hydroxypropionate (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 279-281 
    Details
    ISSN: 0009-2940
    Keywords: Methyl trifluoropyruvate ; Tris(trimethylsilyl) phosphite ; Methyl 2-[bis(trimethylsiloxy)phosphoryl]-3,3,3- trifluoro-2-(trimethylsiloxy)propionate ; Bis(trimethylsilyl) [(2,2-difluoro-l-trimethylsiloxy)ethenyl]- phosphonate ; Solid-state structures ; Fluorine ; Phosphorus ; Silicon ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methyl trifluoropyruvate (1) and tris(trimethylsilyl) phosphite (3) reacted to give methyl 2-[bis(trimethylsiloxy)phosphoryl]- 3,3,3-trifluoro-2-(trimethylsiloxy) propionate (4). Partial hydrolysis furnished propionate 6, the molecular structure of which was obtained in the solid state. Attempted trimethylsilylation of the methylcarboxylato group in 4 using iodotrimethylsilane caused the formation of bis(trimethylsily1) [(2,2- difluoro- 1 -trimethylsiloxy)ethenyl]phosphonate (8). For comparison, methyl pyruvate (2) and 3 gave methyl 2-[bis(trimethylsiloxy)phosphoryl]-2-(trimethylsiloxy)propionate (5).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300222
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  • 280
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    The Structural Chemistry of Binary Halogen Oxides in the Solid State (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 307-316 
    Details
    ISSN: 0009-2940
    Keywords: Halogen oxides ; Solid-state structures ; Intermolecular interactions ; Halogens ; Oxygen ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The development of new preparative and analytical techniques that allow appropriate handling and characterizations of the capricious halogen oxides have initiated a revival of their chemistry. Due to these recent activities, the amount of well-confirmed knowledge about such oxides has considerably increased. This is especially valid for the structural chemistry in the solid state, which (among other topics) has greatly benefitted from developments in the techniques of in situ crystal growth of low melting substances on a diffractometer. As a consequence, some general crystal chemical features have become apparent: The coordination polyhedra of the halogen oxides can be readily understood in terms of the qualitative VSEPR concept, and there is a pronounced tendency to form mixed valence compounds where the respective valence states can be easily deduced from the coordination polyhedra. Furthermore, intermolecular or interionic bonds are significant, with increasing importance when moving from chlorine to iodine. Finally, ClO2 appears to be the only representative with the halogen in an even oxidation state.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300302
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  • 281
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    Characterization of a [4Fe-4S]-Ferredoxin Model Based on a Concave Tetradentate Thiol Ligand System (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 23-34 
    Details
    ISSN: 0009-2940
    Keywords: Cavitand ; Electrochemistry ; Iron sulfur cluster ; Metalloprotein model ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: NMR and Mössbauer spectroscopy show that a novel tetrathiol ligand, based on the cavitand diphenylglycoluril, encapsulates a 4Fe-4S cluster and induces asymmetry in it. The cluster gives a weak electrochemical current response in DMF, with a half-wave potential for the 2-/3- reduction vs. Fc+/Fc of -1.7 V. Ba2+ ions are adsorbed, according to X-ray analysis of the SEM image of the electrode, and act as modulator and promoter of the electrochemical response. On the basis of cyclic voltammograms it is proposed that this adsorption creates electroactive sites, changing the type of diffusion controlling the mass transport to the electrode from radial to linear, and that it helps the negatively charged complex, which contains a dipole, to approach the negative electrode in an orientation favourable for electron exchange. This feature makes the complex an important model for ferredoxins, in spite of a difference in redox potential.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300105
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  • 282
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    The Synthesis, Crystal Structures and Magnetic Properties of Cu4(AsO4)2(O) and Ba2Cu7(AsO4)6 (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 63-67 
    Details
    ISSN: 0009-2940
    Keywords: Barium ; Copper ; Arsenate ; Magnetic susceptibility ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two new compounds Cu4(AsO4)2O (1) and Ba2Cu7As6O24 (2) were obtained from a mixture of CuO and As2O5 · xH2O heated to 1090°C for 72 h in a BaCO3 flux. Compound 1 was obtained as dark green crystals, belonging to the orthorhombic crystal system. Compound 2 was obtained as light gray to colorless crystals belonging to the triclinic crystal system. The structure of 1 contains two copper ions with distorted trigonal bipyramidal geometries and a third with a distorted square pyramidal geometry. One ‚oxide‘ ion is surrounded by four copper ions in a distorted tetrahedral arrangement. Compounds 2 consists of two chains with alternating units of trigonal bipyramidal CuO5 and square planar CuO4 units, with the oxygen atoms derived from the AsO4 groups. Magnetic susceptibility measurements of 1 and 2 both show effective magnetic moments, μeff=1.90-1.95 B.M./Cu at 25°C, which is consistent with Cu2+ ions having one unpaired electron. Significant antiferromagnetic coupling was revealed by variable temperature measurements. At very low temperatures (15-25 K) samples of both 1 and 2 undergo a transition to a weak ferromagnetic state.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300110
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  • 283
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    Halogen/Metal vs. Hydrogen/Metal Exchange: General or Specific Site Selectivity as Exemplified in the Camphene Series (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 77-82 
    Details
    ISSN: 0009-2940
    Keywords: Monoterpenes ; Sesquiterpenes ; Stereoselectivity ; Alk-l-enyllithium(sodium) Metal exchange, halogen vs. hydrogen ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (Z)-(3,3-Dimethylbicyclo[2.2.1]hept-2-ylidene)methyllithium can be readily generated by treatment of (Z)-3-bromomethylene-2,2-dimethylbicyclo[2.2.1]heptane with tert-butyl-lithium. At -75°C, the organometallic intermediate is configurationally stable and reacts with a variety of electrophiles under stereochemical retention.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300112
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  • 284
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    Chemical Interconversions in the System TP*Zn/CO2/Alcohol [Tp* = Substituted Tris(pyrazolyl)borate]Dedicated to Prof. Walter Siebert on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 101-104 
    Details
    ISSN: 0009-2940
    Keywords: Zinc complexes ; Alkyl carbonate complexes ; CO2 fixation, reversible ; Catalysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The zinc hydroxide complexes Tp*Zn-OH with TpCum,Me = tris(3-cumenyl-5-methylpyrazolyl)borate and TptBu,Me = tris(3-tert-butyl-5-methylpyrazolyl)borate can be converted to the alkyl carbonate complexes Tp*Zn-OCOOR by reaction with dialkyl dicarbonates or with alcohol and CO2. An alternative formation reaction is the treatment of the pyrazolyl borate with zinc perchlorate and potassium carbonate in alcohol. The interconversion between TpCum,MeZn-OH and TpCum,MeZn-OCOOMe in methanol-containing solution can be repeatedly performed in both directions by bubbling either CO2 or N2 through the solution. The alkyl carbonate complexes show a variable sensitivity towards hydrolytic destruction with reformation of the hydroxide complexes. The complexes TptBu,MeZn-OCOOR (R = Me, Et) release CO2 under high vacuum to form the alkoxide complexes TptBu,Me-Zn-OR, which could not be obtained pure due to their extreme water sensitivity. Indirect evidence for their existence is also obtained by the reaction between TpCum,MeZn-OCOOMe and methyl iodide, forming TpCum,MeZn-I and dimethyl ether. The Zinc hydroxide complexes catalyse the formation of diethyl carbonate from ethanol and CO2.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300116
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  • 285
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    Lithium 2,2,6,6-Tetramethylpiperidinoselenolate: An Unsymmetrical Dimer with an Unusually Coordinated Lithium (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 119-122 
    Details
    ISSN: 0009-2940
    Keywords: Selenolate ; Aminoselenolate ; Lithium compound i Ab initio calculations ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Lithium 2,2,6,6-tetramethylpiperidide inserts elemental selenium into its Li-N bond with the formation of lithium 2,2,6,6-tetramethylpiperidinoselenolate 1. In the crystal 1 is an unsymmetric dimer. One lithium atom is coordinated tetrahedrally by two molecules of tetrahydrofuran and two selenium atoms, the other lithium atom exhibits an approximately rectangular-planar coordination by two N,Se-chelating groups. The lithium atoms are bridged by two selenium atoms thus forming a planar Li2Se2 core. Ab initio Hartree-Fock calculations show 1 and the hypothetical symmetric dimer 2 to be of equal energy, whereas the non-chelated dimer 3 is of distinctly higher energy. Exclusive crystallization of 1 is most likely a consequence of its large dipole moment of 6.18 D. Calculations also show that the deformation of the observed geometry around the uniquely coordinated lithium atom in 1 towards distorted tetrahedral or complete planarity leads to an increase of energy. Excessive charge transfer from selenium to nitrogen explains the overwhelming tendency for the N,Se-chelating bonding.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300120
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    Masthead (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300201
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  • 287
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    Synthesis, Characterization and Polymerization Behavior of {(1R, S)-2-(η5-9-Fluorenyl)-1-[η5-(1R,S)-indenyl]-1-phenylethane}zirconium dichloride and {(1R,S)-Cyclohexyl-2-(η5-octahydro-9-fluorenyl)-1[η5-tetrahydro-(1R,S)-indenyl]ethane}zirconium Dichloride (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 747-751 
    Details
    ISSN: 0009-2940
    Keywords: Epoxides ; Fluorenyl ligands ; ansa-Zirconocenes, non-symmetrical ; Polymers ; Polymerizations ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Epoxystyrene (1a) were converted into their corresponding alcohols, 2a-c, by treatment with either fluorenyl- or indenyllithium. These alcohols were then further converted into their trifluoromethanesulfonate derivatives, 3a-c. Subsequent reaction of the triflates with fluorenyl-, indolyl-, or tetraphenylcyclopentadienyllithium resulted in formation of 2-(9-fluorenyl)-1(1-indenyl)-1-phenylethane (4a), and 1-(9-fluorenyl)-2-(5-tetraphenylcyclopentadienyl)ethane (4c). The ansa-metallocene (1-(R,S)-2(η5-9-fluorenyl)-1-[η5-1(R,S)-indenyl]-1-phenylethane]ZrCl2 (5a) was prepared from the dilithio salt of 4a. Hydrogenation of 5a with H2/PtO2 leads to {1(R,s)-cyclohexyl-2-(η5-octahydro-9-fluorenyl)-1-[η5-tetrahydro-1(R,S)-indenyl]ethane]ZrCl2 (6a. The complexes 5a and 6a were activated with methylalumoxane (MAO) and used for propene polymerization. The solid state structures of 4b, 4c, and 5a are reported.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300612
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  • 288
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    1,4,7,10,13,16,19,22-Octaazacyclotetracosane-1,4,7,10,13,16,19,22-octaacetic Acid (H8OTEC) and 1,4,7,10,14,17,20,23-Octaazacyclohexacosane- 1,4,7,10,14,17,20,23-octaacetic Acid (H8OHEC): Synthesis and Characterization of Two Large Macrocyclic Polyamine Polycarboxylic Ligands and Some of Their Copper(II) and Lanthanide(III) Complexes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 267-277 
    Details
    ISSN: 0009-2940
    Keywords: Macrocyclic ligands ; Lanthanides ; Copper ; Polyamines ; Polycarboxylic acids ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The optimized synthesis of two new macrocyclic polyamine polycarboxylic ligands, 1,4,7,10,14,17,20,23-octaazacyclohexacosane-1,4,7,10,14,17,20,23-octaacetic acid (H8OHEC) (10) and 1,4,7, 10,13,16,19,22-octaazacyclotetracosane-1,4,7,10, 13,16,19,22-octaacetic acid (H8OTEC) (12), is presented. The key step in the synthesis of both is the high yield carboxymethylation of the corresponding macrocyclic amines using tert-butyl bromoacetate followed by acidic hydrolysis of the acetate protecting groups. The molecular structures of the intermediates 1,4,7,10,14,17,20,23-octaazacyclohexacosane (OHEC-amine) (8), and octa-tert-butyl 1,4,7,10,13,16,19,22- octaazacyclotetracosane-1,4,7,10,13,16,19,22-octaacetate (OTEC-ester) (11) are determined by X-ray crystal structure analysis. OHEC-amine 8 reacts with 2 equiv. of CuSO4 yielding the dinuclear complex [Cu2(OHEC-amine)](SO4)2 (13). Complex 13 crystallizes with 16 molecules of water. 13 · 16 H2O contains two copper atoms, which are coordinated in a strongly distorted octahedral fashion by four nitrogen atoms, one oxygen atom from the sulfate dianion and one oxygen atom from a water molecule. The new ligands 10 and 12 are fully characterized by 1D- and 2D-NMR spectroscopy. Both ligands form dinuclear lanthanide(III) chelates (Ln=Y, Sm, Eu, Gd, Yb, Lu), which are stable and highly water soluble. With lanthanum(III) only mononuclear complexes are formed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300221
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    Masthead (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300301
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    Diazosulfonate Substitutents: A Route to Transition-Metal Complexes with Switchable Water Solubility (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 515-520 
    Details
    ISSN: 0009-2940
    Keywords: Water-soluble ligands ; Diazo compounds ; Photolysis ; Cleavage reactions ; Zinc ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The single-crystal X-ray structure analysis of the diazosulfonate p-H2N-C6H4-N=N-SO3Na 3 features a Z configuration of the diazo moiety and a nitrogen-sulfur bond. Each sodium atom is coordinated by one diazosulfonate substitutent in a chelating manner. Upon reaction of 3 with excess salicylaldehyde, the highly water-soluble Schiff base ligand 6 is obtained in good yield. Treatment of ZnCl2 with 2 equiv. of 6 gives the zinc complex 7. In all cases, the solubilizing diazosulfonate groups can be cleaved off photolytically, which offers an opportunity to precipitate the molecules from their aqueous solutions.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300411
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  • 291
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    Mono- and Bicyclic Organometallic Ring Systems with Exocyclic C=C and C=S BondsDedicated to Professor Joachim Strähle on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 871-877 
    Details
    ISSN: 0009-2940
    Keywords: Cobalt ; Cyclopentadienyl complexes ; Heterocycles ; Electrophilic addition ; Insertion reaction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The cobaltaheterocycles [C5H5Co{κ2(C,S)-C(=CH2)-N(R)C(=S)S](PMe2Ph)] (5-7), which contain both an exocyclic C=C and C=S bond, were prepared from the iminoacylcobalt compounds [C5H5Co(C(CH3)=NCH} (PMe2Ph)]I (2-4) on treatment with either CS2/NaOCH3 or K[S2CNMe2], respectively. While protonation of 5 (R = CH3) and 7 (R = CH2Ph) with HBF4 occurs at the exocyclic C=CH2 bond to give cations containing a CoC(CH3)N(R)C(=S)S ring, the methylation of 5 and 7 with [OMe3]BF4 takes place at the exocyclic C=S bond and generates five-membered heterocycles heterocycles with an SCH4 substituent. The reaction of 5-7 with S8 leads to the elimination of the phosphane ligand and affords the bicyclic dithiolenecobalt complexes 14 - 16 in moderate to good yields. On treatment of 5-7 with C2(CO2R′)2 (R′ = Me,Et), an insertion of the alkyne into the C=CH2 bond occurs and five-membered ring systems 19-22 with an unsaturated exocyclic =C(CO2R′)-C(CO2R′)=CH2 group are formed. As in the case of 5 and 7, protonation and methylation reactions of 19 also take place at different sites leading to cations with either a delocalized CoCN or NCS unit.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300710
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    Nickel(II) Complexes of Chiral Tripodal N,O,S-Ligands: Square-Planar vs. pseudo-Octahedral Coordination in the Solid State and in Solution, Metal-Induced Racemization of the Ligand (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 891-897 
    Details
    ISSN: 0009-2940
    Keywords: Ligands, tridentate ; Nickel ; Thioethers ; Bioinorganic chemistry ; Racemization ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The complexation behavior of three chiral, tripodal N,O,S-ligands with nickel(II) salts was examined. It was found that the coordination mode of the ligands (bidentate N,O and N,S; tridentate N,O,S) and of the central nickel ion (square-planar vs. pseudo-octahedral) is not simply an intrinsic property of the ligand-metal combination, but also a function of the counter ions and of the solvent of crystallization. In the case of one ligand, a diamagnetic square-planar and a paramagnetic pseudo-octahedral form could be switched back and forth, by just changing the solvent of crystallization from methanol to ethanol. By using an enantiomerically pure tripodal N,O,S-ligand, a metal induced racemization was unveiled which would have otherwise remained undetected.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300713
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    Chemistry in Environmentally Benign Media, 8Part 7: Ref. Hydroxymethyl Functionalized Phosphanes as Building Blocks to new Water-Soluble Gold(I) Complexes - synthesis, Characterization, and X-ray crystal Structures of Novel Tetrahedral [Au{P(CH2OH)3}4]+ and Trigonal Planar [Au(Ph2PCH2OH)3]+ Gold (I) Complexes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 907-911 
    Details
    ISSN: 0009-2940
    Keywords: Hydroxymethyl phosphanes ; Gold ; Trigonal gold(I) complexes ; Tetrahedral gold(I) complexes ; P ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions of water-soluble phosphanes P(CH2OH)3 (1) and Ph2PCH2OH (2) with NaAuCl4 in aqueous or alcoholic media, produced the water/alcoholic-soluble AuI complexes [Au(Ph(CH2OH)3)4]+ (3) and [Au(Ph2PCH2OH)3+ (4) in near quantitative yields. The X-ray structures of 3 and 4, reported in this paper, confirm the structures of these new generation of water-soluble transition metal complexes. All compounds were characterized by 1H-, 13C-, 31P-NMR spectroscopy and mass spectrometry. The structures of 3 and 4 were determined by X-ray crystallography.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300716
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    N-Alkylation of Ammine - Undecahydro-Closo-dodecaborate(1-)Dedicate to Prof. Dr. Walter Siebert on the occasion of hbis 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 795-799 
    Details
    ISSN: 0009-2940
    Keywords: Boron ; Alkylations ; N ligands ; Dodecaborate ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions of the ammine-undecahydro-closo-dodecaborate(1-) anion with alkyl halides have been studied in detail. The degree of alkylation of the nitrogen was found to be dependent upon the steric demands of the alkyl groups. The derivatives were characterized by NMR and infrared spectroscopy. Four compounds were crystallized for single crystal X-ray diffraction studies. The tetrahedral coordination of the nitrogen atom of the bis-alkylated derivatives was found to deviate towards planarity with increasing steric hindrance of the substitutents. - The syntheses, crystal structures, and spectral properties of four N-alkyl derivatives of [H3N—B12H11]-, ammine - undecahydro-closo-dodecaborate(1-) (3), are reported. Alkylation of 3 with ethyl iodide was achieved in dimethyl sulfoxide using potassium hydroxide as base. This led to orthorhombic crystals of [N(nC4H94][(CH3CH2)3N—B12H11] (4). The reaction of 3 with benzyl chloride resulted in the bisbenzylated product, isolated as triclinic crystals of [PPN][(C6H5CH2)2 NH—B12H11] (5). The alkylation of 3 with 2-bromopropane gave a mixture of the mono- and bisalkylated products. The monoalkylated derivative [PPN][(CH3)2CH)NH2-12H11] (6, crystallized in the triclinic space group p1) and the bisalkylated product [PPN]{[(CH3)2NH—B12H11) (7, monoclinic, P21./c) were separated on the basis of their different water solubilities. The solid-state structures of the compounds 4-7 revealed a slight distortion of the B12 icosahedron. The length of the B(1)-N(1) bond was found to be dependent on the steric requirements of the attached amine, e.g. primary amine 〈 secondary amine 〈 tertiary amine. This is demonstrated by the variation in the B—N bond length; from 157.8(2) pm for 6, 158.5(5) pjm for 5, 160.0(3) pm for 7, to 163.7(6) pm for 4.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300619
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    Unusual Ring-Closure Reactions During the Oxidation of 1,1′-Bi(3-methylphosphol-2-ene) with Hexafluoroacetone  -  Formation of a Tricyclic Fluorine-Containing PhosphoraneDedicated to Professor Rudolf Taube on the occasion of hbis 65th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 819-822 
    Details
    ISSN: 0009-2940
    Keywords: Hexafluoroacetone ; Phosphorus, pentacoordinated ; Diphosphane diselenide ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reduction of the isoprene - PCl3 adduct 1 with magnesium powder, or with Si2Cl6, furnished P-chloro-3-methyl-phosphol-2-ene, 2, in satisfactory yield. Further reduction of 2 with Si2Cl6 gave the new trichlorosilyl-3-methylphosphol-2-ene, 3. The reaction of 2 with magnesium powder, with 3, or with 1/2 equivalent of Si2Cl6 provided the new γ3P-γP-diphosphane 1,1′-bi(3-methylphosphol-2-ene) 4. Reduction of 4 with Si2Cl6 led to 3. Oxidation of 4 with selenium gave the 1,2-diphosphane diselenide, 5. The oxidation of 4 with hexafluoroacetone led to a mixture of products, from which a novel tricyclic phosphorane 6 was separated. the structure of 196 was determined by X-ray diffraction; the coordination geometry at phosphorus in distorted trigonal bipyramidal, with a very long equatorial P - C(CF3)2 bond of 193.2(2) pm.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300623
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    Organophosphorus Compounds, 119Part 118: Ref.. The Phosphaalkyne Cyclotetramer System  -  Syntheses, Valence Isomerizations, and Reactions (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 823-834 
    Details
    ISSN: 0009-2940
    Keywords: Phosphaalkynes ; Phosphaalkyne cyclotetramers ; Cage compounds ; Valence isomerization ; Cyclotetramerization ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In contrast to their all-carbon analogues, phosphaalkyne cyclooligomers only became accessible a few years ago. A milestone in the chemistry of cyclotetramers was the synthesis and structural characterization of the tetraphosphacubane 5, obtained as a thermolysis product of tert-butylphosphaacetylene (1). Since then, the construction of eleven cyclotetramers has been achieved, covering seven different frameworks (A-G). As a consequence of the use of kinetically stabilized phosphaalkynes as starting materials, all known cyclotetramers bear sterically demanding substituents (tert-butyl, tert-pentyl, 1-adamantyl). Cyclotetramerizations are not only achieved by thermolysis of 1, but also by alternative and selective routes such as transition-metal-mediated, Lewis acid- and base-induced processes, as well as by cycloadditions to phosphaalkyne cyclotrimers. Interestingly, these tetramers can be interconverted by various valence isomerizations. The results of thermal and photochemically-induced rearrangements are in good agreement with MO calculations carried out for the parent compounds. Phosphaalkyne cyclotetramers exhibit a highly interesting reactivity and other peculiar features. One outstanding example is the tetraphosphacubane 5, which shows unusual structural and spectroscopic properties as a result of its unique bonding arrangement.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19971300703
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    2-Phosphanylphosphinines as Bridging Ligands for Dinuclear Transition Metal Carbonyls (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 843-849 
    Details
    ISSN: 0009-2940
    Keywords: P ligands ; Phosphorus heterocycles ; 2-Phosphanylphosphinines ; Dinuclear complexes ; Metal carbonyls ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 2-phosphanyl-4,5-dimethylphosphinines 1-5 are powerful bridging ligands able to stabilize metal-metal single and triple bonds between low-valent transition metal centres. Their reaction with Mn2(CO)10 in refluxing xylene yields the corresponding Mn2(CO)8 complexes 6 and 7. Reaction with [Fe2Cp2(CO)4] under UV irradiation similarly yields the Fe-Fe-bridged Fe2Cp2(CO)2 complexes 8 and 9. An additional observation is that the 2-phosphininyl-3,4-dimethylphosphaferrocene 10 is formed upon reaction of the 2-phospholylphosphinine 5 with [Fe2Cp2(CO)4] at high temperature under CO pressure. A clean addition occurs at the Mo≡Mo triple bond of [Mo2Cp2(CO)4] to give the Mo-Mo single-bonded complexes 11-15. The thermolysis of these complexes succeeds when the phosphanyl group is a phosphonite P(OEt)2 (13) or P(OAr)2 (14), affording cleanly the Mo2Cp2(CO)4 triple-bonded complexes 16 and 17, respectively. The metal-metal triple bonds of these complexes readily add two molecules of CO to reform 13 and 14, or one molecule of tBu-N≡C to give 18 and 19. The X-ray crystal structure analysis of the MO2C2(CO)4 complex 13a, with the 2-P(OEt)2- phosphinine, shows a gauche orientation of the two Cp rings and very short P-Mo bonds of 2.3565(4) and 2.406(2) Å to the phosphinine and P(OEt)2 groups, respectively.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300706
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  • 298
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    The Chemistry of Metallacyclic Alkenylcarbene Complexes, 8Part 7: Ref. Chelated Allyl-Ironcarbene Complexes with a Centrally Tethered π-Ligand-Synthesis and Reactions with Nucleophiles (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 863-869 
    Details
    ISSN: 0009-2940
    Keywords: Carbene complexes ; Iron ; Alkene complexes ; Carbamates ; Trimethylenemethane complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The title complexes 8 and 9 are easily prepared in two or three steps from iron carbonyls and isobutene diol 5 by Meerwein alkylation of the intermediate acyl complexes 6 and 7. With carbon and heteroatom nucleophiles like enolates and triphenylphosphane they form either stable 4-substituted alkene-carbene complexes 10 and 11, or substituted trimethylenemethane tricarbonyliron complexes like 12. Oxidation with H2O2/NaOH both of the alkene-carbene complexes 11 and of the less stable β-oxo-substituted trimethylene-methane complexes 13, as obtained from reaction of 8 with lithium enolates, yields the corresponding substituted allyl carbamates 15 or the allyl alcohols 14, which are formally bis- and monosubstituted derivatives, respectively, of the starting isobutene diol.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300709
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  • 299
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    Chiral Polysiloxane-Fixed Metal 1,3-Diketonates (Chirasil-Metals) as Catalytic Lewis Acids for a Hetero Diels-Alder Reaction -Inversion of Enantioselectivity Upon Catalyst -Polymer Binding (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 879-885 
    Details
    ISSN: 0009-2940
    Keywords: Asymmetric catalysis ; Cycloadditions ; Lewis acids ; Polymers ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A dimethylpolysiloxane chain is covalently bound to the monomeric Lewis acid catalyst (1R)-(+)-oxovanadium(1V) bis[3- heptafluorobutanoylcamphorate] [(+)-5a] at the C-10 position of the camphor moiety yielding the novel chiral polymeric (1S)-( +)-oxovanadium(1V) bis[3-heptafluorobutanoylcamphorate] -dimethylpolysiloxane [( +)-6a][1]. The Lewis acid promoted hetero Diels-Alder reaction of trans-l-methoxy-3-(trimethylsilyloxy)- 1,3-butadiene (1) and benzaldehyde (2) is studied in the presence of the enantiomerically pure monomeric (5a, 5b) and polymeric (6a, 6b) catalysts. The monomeric and polymeric catalysts of identical chirality[1] invoke opposite enantioselectivities toward the formation of 2-phenyl- 2,3-dihydro-4H-pyrone (4). This remarkable result is corroborated by numerous control experiments. Thus, it is demonstrated that the environment of the active site of the catalyst is changed when the complex is fixed to a polymeric chain. In contrast to 5 and 6, the monomeric 12 and polymeric 13 europium(III) tris[3-heptafluorobutanoylcamphorates] of identical chirality invoke the same enantioselectivity toward the formation of 4. The concept of polymer attachment is utilized to recover the catalyst from the reaction mixture by precipitation and to recycle it for subsequent catalytic runs.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300711
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    Cp3Zr(acetonitrile)+: Structure of an Electron-Rich Organometallic d0-Cation (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 899-902 
    Details
    ISSN: 0009-2940
    Keywords: Cp3Zr complexes ; Cationic organometallic Lewis acid ; d0-Configured metal complex ; Acetonitrile ; crystal structure analysis of Zirconium ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The organometallic salt [Cp3Zr(N≡C-CH3)]+ [CH3B-(C6F5)3]- (3a) has been prepared by treatment of Cp3ZrCH3 with B(C6F5)3 followed by the addition of acetonitrile. X-ray crystal structure analysis of 3a shows that its cation consists of three uniformly coordinated η5-cyclopentadienyl ligands about the zirconium atom. The acetonitrile ligand is end-on coordinated. In the linear [Zr] -N≡C-CH3 unit the C≡N triple bond [N-C2 1.126(5) Å] is slightly shorter than in the free acetonitrile molecule [dC≡N = 1.141(2) Å], the structure of which was determined as a reference by X-ray diffraction of a crystal obtained by IR-laser-induced zone melting on the diffractometer.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300714
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