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  • 1
    Digitale Medien
    Digitale Medien
    Preparation and Molecular Structures of Tetrahydrofuran, Diethylene Diglycol Dimethyl Ether and 18-Crown-6 Complexes of Strontium and Barium TetrahydridoborateDedicated to Prof. Dr. Nils Wiberg on the occasion of his 60th birthday. (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 455-460 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Strontium bis(tetrahydridoborate)-2 tetrahydrofuran, chain polymer of ; Strontium bis(tetrahydridoborate)-bis(diglyme) ; Barium bis(tetrahydridoborate)-bis(diglyme) ; Strontium bis(tetrahydridoborate)-1,4,7,13,16-hexaoxacyclooctadecane ; Metal-hydrogen-boron bridges ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The strontium and barium tetrahydridoborate complexes M(BH4)2 · 2 diglyme and M(BH4)2 · 18-crown-6 (M = Sr, Ba) have been prepared from the solvates M(BH4)2 · 2 THF by ligand displacement. 11B-NMR and IR data reveal strongly polar bonding of the BH4 groups to the metal centers, and X-ray structural analyses of the diglyme and crown ether compounds show molecular units in which the BH4 group is in contact via three H atoms with the metal center. In contrast, M(BH4)2 · 2 THF compounds are chain polymers in the solid state, and each metal center is surrounded by 2 THF molecules in trans position and four BH4- groups each of which forms bridges with two metal centers. Estimations of the effective radius for the BH4 group indicate a high polarity for the M-BH4 interaction.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280504
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  • 2
    Digitale Medien
    Digitale Medien
    Synthesis of Structures of (Acyloxy)boranesDedicated to Prof. Dr. A. Schmidpeter on the occasion of his 65th birthday.Synthesis of Structures of (Acyloxy)boranes (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 751-762 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Trifluoroacyloxy-9-borabicyclo[3.3.1]nonane ; Pivaloyloxy-9-borabicyclo[3.3.1]nonane dimer ; Bis(9-borabicyclo[3.3.1]nonyl]oxalate ; Tetrakis(9-borabicyclo[3.3.1]nonyl)-dihydroxyoxalate ; Bis(9-borabicyclo[3.3.1]nonyl)-2,2-dimethylmalonate tetramer ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 9-Borabicyclo[3.3.1]nonane (9-BBNH) reacts with monocarboxylic acids to afford 9-(acyloxy)-9-borabicyclo[3.3.1]nonanes which are dimers in the solid state as shown by X-ray crystal structures of the benzoate and pivalate. More complex reactions were observed by allowing 9-BBNH to react with dicarboxylic acids in THF or monoglyme. Thus, (9-BBN)2 oxalate 3 contains a fully delocalized oxalate unit with equal C-O and B-O bond lengths. Traces of water convert it into the tetrakis(9-BBN) oxalate 5. A rather unusual structure is veryfied by 9-BBN 2,2-dimethylmalonate 7 which according to its molecular structure is a tetramer featuring a 32-membered ring system. In contrast, reactions of oxalic acid with thexylborane leads to reduction of the acid and formation of a bicyclic dioxaborolo-dioxaborolane 10. Several intermediates were detected by 11B-NMR spectroscopy as well as in reactions of BH3 · THF or BH3 · SMe2 with oxalic acid.  -  It follows from the present study that (acyloxy)boranes derived from dicarboxylic acids are strong Lewis acids with an unexpected variety of structural features.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280803
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  • 3
    Digitale Medien
    Digitale Medien
    Contributions to the Chemistry of Boron, 231Part 230: Ref.. Synthesis and Structures of Borylated HydrazinesDedicated to Professor H. P. Fritz on the occasion of his 65th birthday. (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1187-1194 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Hydrazines ; N,N'-bis(diphenylboryl)-N,N'-dimethyl- ; N,N'-bis(diphenylboryl)-N',N'-dimethyl- ; N,N'-bis(dimethylphenylsilyl)- ; N,N'-bis(chloromesitylboryl)-N'-phenyl-N'-(trimethylsilyl)- ; 1,2,4,5,3,6-Tetrazadiborinane, 1,2,4,5-tetrakis(tert-butyldimethylsilyl)-3,6-difluoro- ; Triazadiborolidine, dihydro-, derivative ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The diboration of the diazene PhN = NSiMe3 (15) by diborane(4) derivatives provides a new synthetic route to N,N'-diborylated hydrazines. The product formed depends on the type of the diborane(4) compound. Thus, addition of dimesityldiboron dichloride to 15 in a 1:1 ratio afforded (mesCIB)PhN-N(SiMe3)(BClmes) (16) while bis(dimethyl-amino)diboron dichloride was found to react in a 1:2 ratio to give a triazadiborolidine derivative 17. In addition, it was demonstrated that in the solid state Me2N-N(BPh2)2 (8) is a derivative of a three-membered dihydroazadiboriridine C while its isomer, (Ph2B)MeN-NMe(BPh2) (7), forms no BN coordinative bond. The new 3,6-difluoro-1,2,4,5-tetraza-3,6-diborine 13 shows a twist conformation. The molecular structures of all these compounds were determined by X-ray crystal structure analysis, and the influence of the B substituent on the conformation is discussed.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951281209
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  • 4
    Digitale Medien
    Digitale Medien
    Synthesis and Structures of Bis(tetramethylipiperidino)aluminum Halides-X-ray Crystal Structures of tmp2AlX (X = Cl, Br, I) and [tmp2A1(μ-F)l2 (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1047-1052 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Bis(tetramethylipiperidino)aluminum halides ; Alkoxy((tetramethylpiperidino)aluminum halides ; 27Al-NMR spectra ; Aluminum ; Amides ; Synthetic methods ; Bridging ligands ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: N-Lithio-2,2,6,6-tetramethylpiperidine [Li(tmp)] reacts with AlX3 (X = Cl, Br) in diethyl ether/ n-hexane solution to generate the products of substitution and ether cleavage, [tmpAl(X)(μ-OEt)], (la, X = Cl; 1b, X = Br). However, when the reaction is allowed to proceed in n-hexane alone, an almost quantitative yield of compounds tmp2AlX (2a, X = Cl; 2b, X = Br; 2c, X = I) is obtained. According to 27AI-NMR spectroscopy, mass spectroscopy, cryoscopy, and X-ray crystal structure determinations, these compounds are monomeric in the solid state, in solution, and in the gas phase. 2b reacts with AgBF4 yielding the fluoride-bridged dimer (tmp2AlF), 2d, as shown by X-ray crystal structure determination.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300805
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  • 5
    Digitale Medien
    Digitale Medien
    4-Chlor-1,2,3,5-dithiadiazolium-Salze (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 416-423 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: 4-Chloro-1,2,3,5-dithiadiazolium SaltsThe synthesis of 4-chloro-1,2,3,5-dithiadiazolium chloride (9) from SCI2 and either N-cyanosulfur difluoride imide (8) or bis(trimethylsilyl)carbodiimide (12) is described. The analogous dibromide 13 is formed from S2Br2 and 8. The ionic chlorine in 9 may easily be exchanged with the help of silver salts, acids, and Lewis acids yielding ClCN2S2+A- (9a-d, A- = AsF6-, SbCl6-. ½SnCl62-, SO3-). The crystal structure of the hexafluoroarsenate 9a has been determined.
    Notizen: Die Synthese von 4-Chlor-1,2,3,5-dithiadiazolium-chlorid (9) aus N-Cyanoschwefeldifluoridimid (8) bzw. aus Bis(trimethylsilyl)carbodiimid (12) und SCI2 wird beschrieben. Das zu 9 analoge Dibromid 13 entsteht aus 8 und S2Br2. Mit Hilfe von Silbersalzen, Säuren und Lewis-Säuren läßt sich das ionisch gebundene Chlor in 9 leicht austauschen unter Bildung von CICN2S2+A- (9a-d, A- = AsF6-, SbCl6-, ½SnCl62-, SO3F-). An dem Hexafluoroarsenat 9a wurde eine Kristallstrukturbestimmung durchgeführt.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19831160203
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  • 6
    Digitale Medien
    Digitale Medien
    Bis(di-tert-butylphosphanyl)methan-Komplexe des Rhodiums: Geometrie, Elektronenstruktur und Derivate des 14-Elektronenteilchens [Rh(dtbpm)Cl]. Molekülstruktur von Rh(dtbpm)Cl(PMe3) (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 353-365 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Rhodium(I) phosphane complexes ; 14-Electron intermediates ; MO theory, applied ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Bis(di-tert-butylphosphanyl)methane Complexes of Rhodium: Geometry, Electronic Structure, and Derivatives of the 14-Electron Fragment [Rh(dtbpm)Cl]. Molecular Structure of Rh(dtbpm)Cl(PMe3)14-Electron fragments [M(PR3)2X] (M = Rh, Ir, X = halogen etc.) are considered to be an important class of highly reactive, coordinatively unsaturated intermediates in many metal-induced stoichiometric or catalytic transformations of organic substrates. As available theoretical data suggest a slightly preferred T-shaped groundstate geometry with a less symmetric cis rather than the usually implied trans phosphane arrangement for such tricoordinate d8-ML3-type systems with monodentate phosphanes PR3, the chemistry of η2-diphosphanylmethane complexes of rhodium with four-membered RhPCP-chelate rings and thus with enforced cis phosphane coordination and anomalously small cis P - Rh - P angles has been studied by theory and by experiment. MO calculations (EH) have been performed both for the model 14-electron system [Rh(dhpm)Cl] (dhpm = diphosphanylmethane, H2P - CH2 - PH2) and for the experimentally accessible fragment [Rh(dhbpm)Cl], where dtbpm is bis(di-tert-butylphosphanyl)-methane, (tBu)2P - CH2 - P(tBu)2. The electronic and geometric structure of these species is described. Employing the unusual ligand dtbpm, tailor-made for stabilizing mononuclear η2- and destabilizing dinuclear μ-diphosphanylmethane coordination, the chloro-bridged dimer [Rh(dtbpm)Cl]2, has been synthesized. In agreement with steric and electronic considerations, its chemistry is dominated by a facile dissociation to monomeric (presumably solvent coordinated) fragments [Rh(dtbpm)Cl], even in benzene, as suggested by molecular mass determinations. Accordingly, by using [Rh(dtbpm)Cl]2 as a starting material, a series of sterically very congested but nevertheless mononuclear, square-planar complexes Rh(dtbpm)Cl(L) (L = CO, PMe3, PPh3, PCy3, pyridine, acrylonitrile) with chelating dtbpm could be readily prepared and fully characterized. The relative stability of these potential alternative precursors of a [Rh(dtbpm)Cl] intermediate towards dissociation of ligands L is reported. The molecular structure of Rh(dtbpm)Cl(PMe3) as the first representative of this class of compounds has been determined by X-ray crystallography.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19921250212
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  • 7
    Digitale Medien
    Digitale Medien
    Contributions to the Chemistry of Boron, 230Part 229: Ref.. Electrophilic Borylation of Metallocenes: Synthesis and Molecular Structures of 1,1′,3,3′-Tetrakis(dibromoboryl)metallocenes of the Iron TriadDedicated to Prof. Dr. Dr. h.c. Gerhard Fritz on the occasion of his 75th birthday. (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 621-626 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Ferrocene, tetrakis(dibromoboryl)- ; Ruthenocene, tetrakis(dibromoboryl)- ; Osmocene, tetrakis(dibromoboryl)- ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Reactions of metallocenes MCp2 (M = Fe, Ru, Os) with an excess of BBr3 at reflux temperature lead specifically to 1,1′,3,3′-tetrakis(dibromoboryl)metallocenes 3, 7, and 8 in high yield. MeBBr2 and PhBBr2 are less effective borylating agents. X-ray structural analyses of 3, 7, and 8 reveal an increasing tilt of the Br2B groups towards the metal center while retaining the trigonal-planar environment at the boron atoms. This indicates a weak metal-boron interaction of the kind found for carbon-metal interactions in ferrocenyl carbocations.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280615
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  • 8
    Digitale Medien
    Digitale Medien
    Contribution to the Chemistry of Boron, 235. Reactions of Prolinol with Borane-Tetrahydrofuran: Anomalous Dimerization of a 1,3,2-Oxazaborolidine (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 241-246 
    Details
    ISSN: 0009-2940
    Schlagwort(e): (2-Pyrrolidinylmethoxo)borane, anomalous dimer ; 5-Phenyl-3,4-dimethyl-1,3,2-oxazaborolidine, anomalous dimer ; Reaction intermediates ; Boron compounds ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The reaction of (S)-prolinol (LH) with H3B · THF proceeds via [L2BH2〈]BH4, which decomposes with elimination of hydrogen at ca. -40°C to give the BH3 adduct of spirocyclic 7. On heating, 7 loses more H2 to give the “anomalous” dimerization product 11, which features a tetracoordinated B atom in a “tetrahedral” BN2O2 unit and another B atom in an N2BH2 environment. It is also shown that the product resulting from the reaction of pseudoephedrin with H3B·THF undergoes an analogous anomalous dimerization, affording product 8.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971300217
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  • 9
    Digitale Medien
    Digitale Medien
    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
    Schlagwort(e): 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
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 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.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19971301120
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  • 10
    Digitale Medien
    Digitale Medien
    Structural Chemistry of Lithium HydrazidesDedicated to Professor Ernst Biekert on the occasion of his 70th birthday. (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 105-113 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Lithium N,N'-diethylhydrazide hexamer ; Dilithium N,N'-bis(trimethylsilyl)hydrazide tetramer ; [Lithium N,N-bis(trimethylsily)hydrazide]-[dilithium N,N'-bis(trimethylsilyl)hydrazide] dimer ; Dilithium N-phenyl-N-trimethylsilylhydrazide tetramer ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Deprotonation of NH protons, of four diorgano-, organo(trimethylsilyl)- and bis(trimethylsilyl)hydrazines by n-butyllithium in hexane led to the following lithium hydrazides: [Et-(Li)N-N(H)Et]6, (1)6, [Me3Si(Li)N-N(Li)SiMe3]4, (2)4, [Me3Si-(Li)N-N(Li)SiMe3 · (Me3Si)2N-N(Li)SiMe3]2 (3)2, and [Ph-(Li)N-N(Li)SiMe3]4, (4)4, respectively. The structure determination by X-ray methods at low temperature reveals butterfly-shaped Li2N2 structural monomeric units which associate through “laddering” to the observed oligomers thereby generating penta- and hexacoordinated Li centers. N-N bonds lengths of up to 1.556 Å suggest that negative charge accumulates at the nitrogen atoms of (1)6, (2)4, and (3)2. An amazing structure shows the red compound 4 where two Li ions are π-sandwiched between two phenyl groups each. The compound can be looked at as a new type of a lithium lithiate complex, Li2[Li6N8Ph4(SiMe3)4], but short N-C and N-N bonds in the Li6N8 core indicate that its negative charge is transferred to the phenyl groups.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280204
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