摘要：

The reduction of the niobocene complexes Nb(η-C 5H 4SiMe 3) 2X 2 (I: X = Br, II: X = I) with one equivalent of sodium amalgam gives the Nb III solids Nb(η 5-C 5H 4SiMe 3) 2X (III: X = Br, IV: X = I). These complexes can also be obtained by treatment of Nb(η 5-C 5H 4SiMe 3) 2H 3 (V) with one equivalent of EtBr or MeI. Reactions of III and IV with CO, PhCCPh, P(OMe) 3 and CN(2,6-Me 2C 6H 3) give the solid 1 1 adducts Nb(η 5-C 5H 4SiMe 3) 2XL (VI: X = Br, L = CO; VII: X = Br, L = PhCCPh; VIII: X = Br, L = P(OMe) 3; IX: X = Br, L = CN(2,6-Me 2C 6H 3); X: X = I, L = CO; XI: X = I, L = PhCCPh; XII: X = I, L = (P(OMe) 3; XIII: X = I, L = CN(2,6-Me 2C 6H 3). The carbenoid-like III reacts with cumulenes to give the complexes Nb(η 5-C 5H 4SiMe 3) 2Br(XCY) (XIV: X = Y = S; XV: X = PhN, Y = O; XVI: X = PhN, Y = S). The hydride complexes Nb(η 5-C 5H 3RR′) 2HL (XVII: R = H, R′ = SiMe 3; XVIII: R = R′ = SiMe 3) have been prepared by treating the trihydride complexes Nb(η 5-C 5H 3RR′) 2H 3 in the presence of CO. The related complexes Nb(η 5-C 5H 3RR′) 2HL(XIX: R = H, R′ = SiMe 3, L = PhCCPh; XX: R = H, R′ = SiMe 3, L = P(OMe) 3) were made by reaction of Nb(η 5-C 5H 4SiMe 3) 2XL with an excess of NaA1H 2(OCH 2CH 2OMe) 2.

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