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  • 1
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 2199-2207 
    ISSN: 0009-2940
    Schlagwort(e): Zinc complexes ; Low coordination ; Amide complexes ; Thiolate complexes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Three different thiophenoles 2,4,6-(CF3)3C6H2SH (4), 2,4,6-(iPr)3C6H2SH (5), and 2,6-(Me3Si)2C6H3SH (6) with bulky sub-stituents in ortho position were treated with Zn[N(SiMe3)2]2 (7) in a non-coordinating solvent like CH2Cl2 or toluene to yield mixed amide thiolate zinc complexes Zn2[N(SiMe3)2]{S[2,4,6-(CF)3C6H2]}3 (8), Zn3[N(SiMe3)2]2{S[2,4,6-(iPr)3C6H2]}4 (9), and Zn2{S[2,6-(Me3Si)2C6H3]}4 (10), respectively. These compounds comprise low-coordinated zinc atoms. Initially, the reactions were performed in a 1:1 ratio of the reactants. However, in no reaction the expected {Zn[N(SiMe3)2](SR)}x (X = 1,2,3…) species were obtained but compounds which are richer in thiolate substituents (SR/NR2 〉 1) even if a large excess of amide 7 was used. Distinct from these, the reaction between 7 and 2,6-(iPr)2C6H3OH (14) in a 1:1 ratio afforded indeed dimer Zn2[N(SiMe3)2]2{O[2,6-(iPr)2C6H3]}2 (15). The molecular structures of 8, 9, 10, and 15 in the crystal are elucidated by X-ray structural analyses and compared with proposed structures in solution based on multinuclear NMR experiments.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 2
    ISSN: 0009-2940
    Schlagwort(e): Ambiphilic coordination compounds ; Tripod ligands ; Triphosphane ligands ; Tollens reaction ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Ambiphilic Tripod Complexes: Synthesis and Coordination Chemistry of Long-Chained Functionalized Tripod Ligands RC(CH2PPh2)3 with R - Pentyl or 8-NonenylTripod ligands RC(CH2PPh2)3 with R = pentyl (3a) and R = 8-nonenyl (3b) are accessible from the corresponding triols. By using appropriately selected activation procedures the triols 1a, b are transformed into the tripodal ligands 3a, b. In addition to their direct characterisation the tripod ligands 3a, b have been further structurally analysed by the syntheses and X-ray analyses of specific cobalt (4a) and iron (4b) coordination compounds. An interesting side result from the X-ray analysis of [(3b)Fe(NCCH3)3](BF4)2 (4b) is the organisation of its solid-state structure by the hydrophobic 8-nonenyl substituents in the ligand backbone.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2731-2738 
    ISSN: 0009-2940
    Schlagwort(e): Bismuthinidene complexes ; Manganese complexes ; Chelating ligands ; Cumulenes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Treatment of [Cp′Mn(CO)2THF] (Cp′=C5H4Me) with BiCl3 at 20°C affords the “bismuthinidene” species [Cp′- (CO)2Mn]2BiCl (1b) and very small amounts of the “star-type” compound [Cp′(CO)2Mn]3Bi2 (2). Higher yields of both compounds are obtained from the reaction of BiCl3 with [Na] [Cp′(CO)2MnSi(C6H5)3-]. The molecular structure of 1b has been determined by an X-ray diffraction study, which shows that the bismuth atom, having a trigonal-planar coordination geometry, is bonded to two manganese atoms and one chlorine atom. There are weak interactions between the molecules of 1b in the solid state thus forming infinite spiral chains of “inidene” complexes. Compound 1b reacts with NaI to afford the iodine-substituted species [Cp′(CO)2Mn]2BiI (3). Displacement of the chloride substituent from 1b by anionic chelating ligands AB- is also possible; 1b reacts with tropolonate, 8-oxoquinolate, or 8-mercaptoquinolate to form the bismuth(I) chelate compounds [CP′(CO)2Mn]Bi - AB (5a-c). The molecular structure of 5b has been determined by X-ray crystallography which shows the bismuth atom in a pseudo trigonalbipyramidal geometry with the nitrogen atom lying above the plane defined by the two manganese and the oxygen atoms in an apical position. The molecular structure of 5c has also been determined, and although the numerical values are not very accurate, the coordination geometry of the bismuth atom is seen to be intermediate between pseudo trigonalbipyramidal and distorted tetrahedral. Abstraction of a chloride ligand from 1b by Me3SiOSO2CF3 affords the cationic cumulene-type complex [Cp′(CO)2Mn=Bi=Mn(CO)2Cp][CF3SO3] (6a). Dichloromethane solutions of 6a are not stable at room temperature but may be treated with 2,-2′-bipyridine (bpy) to afford the stable adduct [{CP′(CO)2Mn}2Bi(bpy)][CF3SO3](7). The molecular structure of 7 has been determined by X-ray analysis, and - similarly to 5c, although the numerical values are not very accurate - the overall geometry has been determined unequivocally. The bismuth atom is shown to have a distorted tetrahedral geometry, thus being ligated by two manganese atoms and the two nitrogen atoms of the bpy ligands.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 501-506 
    ISSN: 0009-2940
    Schlagwort(e): Tripod ligand synthesis ; Tripod iron trisacetonitrile complexes ; Tripod cobalt acetate complexes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Functionalized Tripod Ligands: Synthesis and Coordination of 1,1,1-Tris[(diphenylphosphanyl)methyl]methaneThe tripod ligand HC(CH2PPh2)3 (4) is easily available from the reaction of 1,3-dichloro-2-(chloromethyl)propane (3) with lithium diphenylphosphide. The ligand 4 itself and two of its coordination compounds, [(HC(CH2PPh2)3)Co(OOCMe)]+-[BPh4]- (5 · BPh4) and [(HC(CH2PPH2)3)Co(OOCMe)]2+ · 2[BF4]- [7 · (BF4)2] have been characterized by X-ray analyses. Coordination of 4 leads to an opening of the CH2—CH—CH2 bond angles (114° in 7 · (BF4)2 and 5 · BPh4 versus 111° in 4). This change in structure is reflected by the unusual low field shift of the methine hydrogen of 7 · (BF4)2 (δ = 3.90) in comparison with the corresponding signal of the free ligand 4 (δ = 1.53).
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 271-274 
    ISSN: 0009-2940
    Schlagwort(e): Pig liver esterase ; Enantioselective hydrolysis ; Asymmetrized neopentane ; Reactive chiral building block ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A Novel Chiral Building Block with Neopentane Framework for Synthesis: Chemo-Enzymatic Preparation of (R)-CH3C(CH2OSO2CF3)(CH2Cl)(CH2Br)The pig liver esterase (PLE) catalysed hydrolysis of the prochiral malonic ester (BzlOCH2)(Me)C(COOMe)2 (1) leads to its chiral monoester 2 in selectivities up to 81% ee. Compound 2 is an ideal entry point for the enantioselective synthesis of 1,1′,1″-substituted neopentanes CH3C(CH2X)-(CH2Y)(CH2Z) with three different leaving groups, X, Y, and Z. CH3C(CH2OSO2CF3)(CH2Br)(CH2Cl) (8) is a versatile reactive building block for the asymmetric synthesis of compounds containing the neopentane-C5 skeleton.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 1031-1035 
    ISSN: 0009-2940
    Schlagwort(e): Lithium-(fluorosilyl)phosphanides ; Phosphanides, lithium-(fluorosilyl)(phosphanyl)- ; Silylidenephosphanes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Evidence for a Structure-Reactivity Relationship of Crowded Substituted Lithium (Fluorosilyl)phosphanidesThe molecular structures and the reactivity of the new solvated lithium (fluorosilyl)phosphanides 1a, 2a, and 2b has been investigated. The unusual solid state structures of 1a and 2b are established by X-ray crystallography. Whereas the lithium centre in 1a is bound to phosphorus and solvated by three molecules of THF, the electronical saturation of the lithium centre in 2b is achieved by a Li—P bond, tridentate chelatization (fluorine, phosphorus, nitrogen), and the additional coordination of one molecule of THF. The trigonal-planar geometry at phosphorus in 1a is unprecedented for derivatives of this type and reflects the steric demand around the phosphorus and the possibility of πp/σ*sic hyperconjugation. The Si—P bond lengths [P—SiC(Phenyl) 2.186(2) and P—SiF 2.164(2) Å] are significantly shorter than in related pyramidally configurated derivatives (1b, c: P—SiC 2.21, P—SiF 2.18 Å). Both phosphorus atoms in 2b are pyramidally coordinated, but the intramolecular chelate coordination of the lithium centre causes much smaller bonding angles at the Si—P phosphorus atom [sum of bonding angles 238.4(2) (PSi), 312.5(1)° (PN)]. 1a as well as 2a, b show quite different reactivity as compared to 1b-d due to their unusual structures. Heating of solutions of 1a and 2a, b in toluene or hexane does not give the expected stable silylidenephosphanes (Si=P) by elimination of LiF. Instead, rearrangement reactions of the Si=P intermediates 6, 8 lead to the new heterocycles 5, 9. A single-crystal X-ray diffraction analysis of 5 has been performed. The Si2P2 cyclobutane ring is planar, and the NMe2 groups at the ring silicon atoms are cis-orientated.  -  Interestingly, 2b eliminates LiNiPr2 at 20°C in a kinetically controlled process to form the tetraphosphacyclobutane 7 as the major product. Presumably, the diphosphene 8 is an intermediate in this reaction.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 1837-1842 
    ISSN: 0009-2940
    Schlagwort(e): Tripod ligand synthesis ; Oxetane cleavage ; Phosphane-Boranes ; Chiral neopentyl system ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Chiral Tripod Ligands: A New Synthetic Route to Chiral C1-symmetrical Neopentyltris(phosphane) Ligands H3CC[CH2P(Ra)2][CH2P(Rb)2][CH2P(Rc)2]A novel synthesis of chiral tripod ligands H3CC[CH2P-(Ra)2][CH2P(Rb)2][CH2P(Rc)2] (6) containing three different donor groups at their neopentyl backbone is described. The key intermediates H3CC[CH2P(Ra)2][CH2P(Rb)2](CH2OH) (3) are easily obtained starting from pentaglycerine, H3CC-(CH2OH)3, via the oxetanes (2) following published procedures. The compounds 3, after protection of the phosphane functions by BH3 {formation of H3CC[CH2P(Ra)2BH3][CH2P(Rb)2BH3](CH20H) (4)} are transformed into the mesylates H3CC[CH2P(Ra)2BH3][CH2P-(RB)2BH3](CH20Ms) (5), which upon reaction with KP(Rc)2 and deprotection with morpholine gives fair yields of racemic 6. The synthetic route described is thus a valuable and efficient alternative to a recently published procedure, based on H3CC(CH2CI)(CH2Br)(CH20S02CF3) as the key intermediate. The compounds 2-6 are obtained in analytically pure form and are fully characterised by spectroscopic data.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
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  • 8
    ISSN: 0044-2313
    Schlagwort(e): SnCl2 bridging ligand ; pentacarbonylmetal derivatives ; organometallic protection ; Sn—O-cage compound ; synthesis ; crystal structure ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: SnCl2 as a Bridging Ligand in [{(CO)5M}2Sn(Cl)2]2- (M = Cr, Mo, W)  -  Synthesis, Structure, and Reactivity[{(CO)5Cr}2Sn(Cl)2]2-, 1, may be obtained from [(CO)5Cr]2- or [(CO)5CrSnCl2 · THF] in fair yields. Alternatively, 1 is accessible by the reaction of [Cr2(CO)10]2- with SnCl2. This procedure may be extended to the synthesis of [{(CO)5M}2Sn(Cl)2]2- (M = Mo, 2; M = W, 3). The compounds 1-3 are crystallized as their alkalimetal (12-crown-4)2 or [2,2,2]cryptand salts. X-ray analyses demonstrate bridging SnCl2-moieties with M—Sn—M-angles close to 130° in each case. The relation of the bonding situation in 1-3 to the ones observed for stannylene or „inidene“ complexes, respectively, is discussed. The transformation of 1 into the rhombododecahedral (X-ray analysis) Sn—O-cage compound [{(CO)5CrSn}6(μ3-O)4(μ3-OH)4], 4, demonstrates the reactivity of the dianions 1-3.
    Notizen: [{(CO)5Cr}2Sn(Cl)2]2, 1, kann aus [(CO)5Cr]2- oder [(CO)5CrSnCl2 · THF] in guten Ausbeuten dargestellt werden. Alternativ ist 1 aus [Cr2(CO)10]2- und SnCl2 zugänglich. Dieses Verfahren kann auf die Synthese von [{(CO)5M}2Sn(Cl)2]2- (M = Mo, 2; M = W, 3) übertragen werden. Die Dianionen 1-3 werden als Alkalimetall-(12-Krone-4)2 oder -[2,2,2]Kryptand-Salze kristallisiert. Einkristallröntgenstrukturanalysen zeigen jeweils die Verbrückung durch die SnCl2-Einheit mit M—Sn—M-Winkeln nahe bei 130°. Die Beziehung der Bindungsverhältnisse in 1-3 zu denen, die in Stannylen- oder „Iniden“-Komplexen beobachtet werden, wird diskutiert.Die Umwandlung von 1 in die rhombendo-dekaedrische (Röntgenstrukturanalyse) Käfigverbindung [{(CO)5CrSn}6(μ3-O)4(μ3-OH)4], 4, belegt die Reaktivität der Dianionen 1-3.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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