摘要 : The reduction of acetonitrile by [BU4N]BH4 at the rhenium(I) metal center in ReCl2(PMe3)(2)(CH3CN)NO to afford ReCl{(muH)B(H)(2)N=C(H)Me}(PMe3)(2)NO (2) is reported. The coordinated immoborane moiety is an intermediate in acetonit... 展开 The reduction of acetonitrile by [BU4N]BH4 at the rhenium(I) metal center in ReCl2(PMe3)(2)(CH3CN)NO to afford ReCl{(muH)B(H)(2)N=C(H)Me}(PMe3)(2)NO (2) is reported. The coordinated immoborane moiety is an intermediate in acetonitrile reduction. A mechanism is proposed for its formation. Further reaction with a hydride source (LiBH4, NaBH4, LiHBEt3) results in replacement of chloride with hydride to give ReH{(mu-H)B(H)(2)N=C(H)Mel}PMe3)(2)NO (3), together with varying proportions of ReH2(PMe3)(3)NO (4). Compounds 2 and 3 have been characterized by NMR and infrared data. The structure of 3 has additionally been elucidated by a single crystal X-ray diffraction study. Crystal data: C8H26BN2OP2Re, triclinic, P (1) over bar, a = 8.821(7) Angstrom, b = 12.4062(11) Angstrom, c = 15.5822(12) Angstrom, alpha = 70.004(9)degrees, beta = 82.726(9)degrees, Z = 4, R = 0.0535, R-w = 0.1325. The H-b/H-t hydrogen exchange process in the iminoborane moiety of 2 and 3 has been studied by NMR spectroscopy and a negative value of DeltaS(#) found for this process. The proposed mechanism for this exchange resembles that of P-hydrogen elimination in metal alkyls. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 84] 收起