Facile conversion of bis(alkynyl) into diyne ligand on platinum assisted by electrophilic gold phosphine

P-31 NMR spectroscopy measurements were used to establish the course for th e stoichiometric-dependent reactions between [Au(PPh3)](+) and [Pt(C drop C Ph)(2)(dppf)] (1), which for equimolar amounts afford as the unique product [Pt-{eta (3)-C(C drop CPh)double bondC(Ph)Au(PPh3)}(dppf)](+) (2), but any excess of 1 gives also [Pt(eta (2)-PhC drop CC drop CPh)(dppf)] (3) [dppf = 1,1'-bis(diphenylphosphine)ferrocene]. Both compounds 2 and 3 were obtain ed straightforwardly by the reactions of 3 with [Au(PPh3)](+) and [Pt(C2H4) (dppf)] with 1,4-diphenylbutadiyne, respectively. The X-ray crystal structu re analysis of 3 confirmed a trigonal-planar coordination geometry about th e platinum atom, and a bent eta (2)-coordinated diyne ligand. (C) 2000 Else vier Science B.V. All rights reserved.