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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 2277-2281 
    ISSN: 1434-1948
    Keywords: Boron ; Iron ; Nickel ; Carbyne complexes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The μ3-boryloxycarbyne complexes [{Fe(CO)3}3{μ3-COBCl{NtBu(SiMe3)}}2] (1) and [{(η5-C5H5)Ni}3{μ3-COBX(NR2)}μ3-CO] (2a: NR2 = NtBu(SiMe3), × = Cl; 2b: NR2 = N(SiMe3)2, × = Cl; 2c: NR2 = NMe2, × = BNMe2Cl) were obtained by reaction of the anionic complexes K2[{Fe(CO)3}3{μ3-CO}2] and K[{(η5-C5H5)Ni(CO)] with the corresponding chloroboranes Cl2BNR2 {NR2 = NtBu(SiMe3), N(SiMe3)2}, or 1,2-dichlorodiboranes(4) B2(NMe2)2Cl2, respectively. The products are formed by a nucleophilic attack of the CO oxygen atom at the boron centres with subsequent salt elimination. All compounds were characterized by IR and multinuclear NMR spectroscopy, and the structures of 1 and 2c in the solid state were determined by single-crystal X-ray diffraction studies.
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  • 2
    ISSN: 1434-1948
    Keywords: Half-sandwich complexes ; Molybdenum ; Optically active complexes ; Rhenium ; Tungsten ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of (η5-PinCp*)Re(CO)3 [PinCp* = tetramethyl(pinanyl)cyclopentadienyl] is described. Successive substitution of two CO ligands by NO+ and PPh3 generates a 1:1 diastereomeric mixture of chiral-at-metal [(SRe)/(RRe)-(PinCp*)Re(CO)(NO)(PPh3)]BF4. The diastereomers are converted with sodium methoxide into the derivative “esters” (SRe)/(RRe)-(PinCp*)Re(COOCH3)(NO)(PPh3), and then with (+)-(R)-(1-naphthylethyl)amine to the “amides” (SRe)/(RRe)-(PinCp*)Re(NO)(PPh3)[CONHCH(CH3)C10H7] [(SRe)/(RRe) = 1:1]. Fractional crystallisation separates the (SRe) isomer with an optical purity of 〉 98%. The latter compound has been characterized by X-ray structure analysis. By treating the (SRe)-amide with CF3CO2H and NaBF4, (SRe)-(PinCp*)Re(CH3)(NO)(PPh3) can be generated. Protolysis of this compound with HBF4/Et2O in CD2Cl2 at -78 °C leads to the solvent-stabilized complex (SRe)-[(PinCp*)Re(NO)(PPh3)(ClCD2Cl)]+BF4-. The thermal and configurational stability of this chiral Lewis acid is investigated at various temperatures. The syntheses of [PinCp*RhCl2]2, PinCp*TiCl3 and PinCp*M(CO)2(NO) (M = Mo, W) are also described. Starting with PinCp*M(CO)2(NO), the relatively stable 16-VE complexes PinCp*MCl2(NO) and PinCp*W(CH2SiMe3)2(NO) are synthesized.
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  • 3
    ISSN: 1434-1948
    Keywords: Boron ; Transition metals ; Sandwich complexes ; Boratabenzene ; Pinene ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Complexes of pinene-fused boratabenzene ligands [(1R,9R)6,10,10-trimethyl-4-boratatricyclo[7.1.1.02,7]undeca-2,4,6trienes] C13H17BX (with a: X = NMe2; b: X = OMe; c: X = Me) are described. The lithium salt Li(C13H17BNMe2) [Li(1a)] reacts with [Cp*Fe(NCMe)3]PF6 and with Mn(CO)3Br(py)2 to give diastereomeric mixtures FeCp*(C13H17BNMe2) (4a) and Mn(CO)3(C13H17BNMe2) (7). The mixture 4a undergoes solvolysis in methanol to produce methoxy compounds 4b, which in turn react with LiMe in Et2O to give methyl derivatives 4c. The lithium salts Li(C13H17BX) [Li(1a-c)] react with ZrCl4 in toluene or Et2O to give exo,exo-ZrCl2(C13H17BX)2 complexes (8a-c). The dimethyl derivative exo,exo-ZrMe2(C13H17BNMe2)2 (9) can also be prepared from 8a/LiMe in Et2O. NOE difference spectra have been analyzed to determine the configurations of the diastereomers and to establish a chemical shift criterion for assessing the configuration of the metal-ligand coordination. An independent confirmation of the product stereochemistries has been obtained by single-crystal X-ray structure determinations of exo-4a and 8a.
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  • 4
    ISSN: 0947-6539
    Keywords: carbon-carbon coupling ; carbonyl complexes ; hafnium complexes ; ketenylidene complexes ; zirconium complexes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The biscyclopentadienyldicarbonyl derivatives of zirconium(II) and hafnium(II) ([MCp2(CO)2]; M=Zr, Hf) promote the reductive coupling of coordinated carbon monoxide to give, in the presence of N,N-dialkylcarbamtes of the tetravalent metals [M(O2CNR2)4], the ketenylidene complexes [M3Cp2(μ2-CCO)-(μ3-O)(O2CNR2)6] (1 a: M=Zr, R=Et; 1 b: M=Zr, R=iPr; 2: M=Hf, R=iPr). The yields of the isolated zirconium complexes are as high as 60%, while that of the hafnium derivative is 40%. The X-ray crystal structure analysis of 1 b shows that it consists of trinuclear molecules, with the three zirconium atoms held together by the bidentate C2O ligand, by the tridentate bridging oxide and by the bidentate carbamato groups. Labelling experiments with [ZrCp2(13CO)2] show that the ketenylidene ligand originates from the coordinated CO groups. These ketenylidene complexes, which are rare examples of compounds containing a CCO but no CO ligand, are characterized by an intense IR band at about 2015 cm-1, associated with the bridging C2O ligand. The ketenylidene group of 1 b was readily removed and replaced by a bidentate μ-oxo ligand of the same hapticity by reaction with carbon dioxide or acetone or by thermal decomposition. The resulting product [Zr3Cp2(μ-O)(μ3-O)-(O2CNiPr2)6] (3) crystallizes in the same space group as 1 b and with similar cell constants and bond parameters.
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  • 5
    ISSN: 0947-6539
    Keywords: carbonyl complexes ; chiral ligands ; iron complexes ; phosphorus ligands ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Secondary phosphines such as HPPh2 and to the cationic iron dienyl complex [η5-(1R)-ethylnopadienyl)Fe-(CO)3]+ (1) by nucleophilic addition. The phosphonium salt initially formed is readily deprotonated to yield an optically active tertiary phosphine [(n4-(1 R)-ethylnopadienePPh2)Fe(CO)3] (2b). A similar reaction also occurs with [C6H7Fe-(CO)3]+ (3) and [C7H9Fe(CO)3]+ (4) to give [(C6H7PPh2)Fe(CO)3] (5) and [(C7H9PPh2)Fe(CO)3] (6) in good yields. The mechanism of formation of these novel phosphines is discussed. Complex 2 b crystallizes in the space group P212121 (no. 19); 5 crystallizes in the space group P21/c (no. 14). Like other monodentate optically active phosphines, 2 b is capable of coordinating to transition metal complexes. It forms palladium complexes on reaction with [{μ-chloro(allyl)palladium}2] as well as with [{μ-chloro[(N,N-dimethylamino-kN-2-methyl)phenyl-kC]palladium}2] (11). The latter reaction product crystallizes in the space group P31 (no. 144).
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  • 6
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of CuO'Bu with CO2, and iPr2NH in the presence of PPh3, gives the dialkylcarbamato complex [Cu(O2CNiPr2)(PPh3)2] (1). The CO2/R2NH system (R = Me, Et) in an appropriate organic medium reacts with Ag2O giving the corresponding N,N-dialkylcarbamato complexes of analytical formula [Ag(C2CNR2)] (R = Me, 2; R = Et, 3). The methyl derivative 2 was characterized by X-ray diffraction methods. Crystal data of 2: for [Ag2(O2CNMe2)2], C6H12Ag2N2O4, mol. wt. 391.9; monoclinic, space group P21/c, a = 12.08(1), b = 3.797(2), c = 11.316(7) Å, β = 113.37(6)°, V = 476.3 Å3, Z = 2, Dc = 2.732 g cm-3; μ(MoKα) = 40.64 cm-1, F(000) = 376.0; R = 0.059, Rw = 0.067; g.o.f. 1.27. The structure consists of dinuclear [(Ag2OCNMe2)2] units with slightly distorted linearly two-coordinated Ag-atoms containing bridging carbamato groups to form a substantially planar eight-membered ring with an intra-annular Ag—Ag distance of 2.837(2) Å; the dinuclear units are further joined by Ag—O bonds to form an infinite array. Compound 3, which is presumably dinuclear, as suggested by cryoscopic measurements in benzene, undergoes a structural fission with PPh3, giving the mononuclear triphenylphosphine derivative [Ag(O2CNEt2)(PPh3)2] (4). The amine-catalyzed conversion of Ag2O into Ag2CO3, in the presence of the iPr2NH/CO2 system, is also reported. Cl-Exchange from [AuCl(PPh3)] with [Ag(O2CNEt2)] (3) gives the first N,N-dialkylcarbamato complex of gold, namely [Au(O2CNEt2)(PPh3)] (5), which crystallizes in the monoclinic system: C23H25AuNO2P · 0.5 C7H16, mol. wt. 625.5, space group P21/c; a = 13.212(5), b = 12.25(1), c = 16.795(6) Å, β = 109.09(2)°, V = 2568(2) Å3, Z = 4, Dc, = 1.618 g cm-3; μ(AgKα) = 31.40 cm-1, F(000) = 1236.0; R = 0.058; Rw = 0.064; g.o.f. 2.121. The compound contains two-coordinated Au-atom, namely to the P-atom and to the O-atom of the monodentate carbamato group, the P—Au—O bond angle being 174.7(3)°. The reaction with MeI showed these compounds to react predominantly at the carbamato O-atom giving the corresponding urethanes R2NCO2Me. Evidence was gathered for the transient coordination of CO to Ag in 3.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 465-468 
    ISSN: 1434-1948
    Keywords: Boron ; Iron ; Boryl complexes ; Borylene complexes ; Iron-boron bond ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Depending on the nature of the amino group bound to the boron atom, the reactions of various aminodichloroboranes R2NBCl2 with Na[(η5-C5R′5)Fe(CO)2] yield either boryl or bridging borylene complexes of iron. The compounds [(C5R′5)(CO)2Fe{BCl(NR2)}] (1a, C5R′5 = C5H5, R = Me; 1b, C5R′5 = C5H4Me, R = Me; 1c, C5R′5 = C5Me5, R = Me) and [(η-BNR2)(μ-CO){(C5R′5)Fe(CO)}2] (2a, C5R′5 = C5H5, R = SiMe3; 2b, C5R′5 = C5H4Me, R = SiMe3) were isolated as orange (1a-c) or red (2a, b) crystalline solids, and characterized by multinuclear NMR methods and IR spectroscopy. The structures of 1c and 2b in the crystalline state were determined by single-crystal X-ray studies.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1563-1566 
    ISSN: 1434-1948
    Keywords: Stannaborate cluster ; Transition metal complexes ; Tin ; Coordination modes ; Clusters ; Boron ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of the stannaborate salt [NBu4]2[SnB11H11] (1) with the organometallic electrophiles [CpFe(CO)2Br], [(C7H7)Mo(CO)2I], and [CpNi(PPh3)Cl] resulted in substitution of the halide to give the stannaborate coordination products [NBu4][CpFe(CO)2(SnB11H11)] (2), [NBu4][(C7H7)Mo(CO)2(SnB11H11)] (3), and [NBu4][CpNi(PPh3)(SnB11H11)] (4) in high yields. Single crystals of the air- and moisture-stable products have been characterized by X-ray crystal structure analyses.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 2000 (2000), S. 735-739 
    ISSN: 1434-1948
    Keywords: Silaboranes ; Cluster compounds ; Siloxanes ; Silicon ; Boranes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of alkoxide adducts of o-silaborane [(TMPDAH)2][(Me2Si2B10H10)2O] (3) and [TMPDAH][(Me2Si2B10H10)OMe] (4) are presented (TMPDA = tetramethylpropylenediamine). For both silaborate clusters 3 and 4 the results of the NMR spectroscopic investigations together with the X-ray single crystal structure determinations are discussed. The geometries of ab initio calculations (HF and B3LYP methods) on the hydroxide adduct [Si2B10H12(OH)]- are compared with the structures of 3 and 4. The dynamic behaviour of the adducts 3 and 4 in solution is discussed with respect to the calculated energy profile for the rotation of the HSi(OH) group.
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  • 10
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
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