摘要:
The mechanism of conversion of terminal alkynes RC CH to coordinated carbyne Os CCH(2)R by Os(H)(2)ClXL(2) (L = P(i)Pr(3)) has been studied for X = OTf and BAr(4)(F) (Ar(F) = 3,5-di(CF(3))(2)(C(6)H(3)). Ready loss of these X makes possible detection of eta(2)-RCCH (4-electron donor) and =CH(CH(2)R) intermediates, and D-labeling (RCCD) gives OsDClX(CCH(2)R)L(2). The energy of various intermediates, including the only experimentally unobserved one, eta(2)-vinyl, was evaluated with DFT(PBE) calculations. (C) 2007 Elsevier B.V. All rights reserved.