Reactivity of [trans-PtH(C CC5H4N-2)(PPh3)(2)] toward [cis-Pt(C6F5)(2)(thf)(2)]. Synthesis of an unusual triplatinum cluster-substituted platinum complex

The complex [trans-PtH(C equivalent to CR)(PPh3)(2)] (1) (R = 2-pyridyl) re acts with [cis-Pt(C6F5)(2)(thf)(2)] under mild conditions to afford initial ly the 1:1 adduct [trans,cis-(PPh3)(2)(H)Pt(mu-1 kappa C-alpha:eta(alpha,be ta)(2): 2 kappa N-C equivalent to CC5H4N-2)Pt(C6F5)(2)] (2), which finally rearranges to form a mixture of [cis,trans(PPh3)(C6F5)(2)Pt-(mu-1 kappa C-a lpha:2 kappa N-C equivalent to CC5H4N-2)Pt+(H)(PPh3)(2)] (5) (X-ray) and a tetranuclear cluster [{cis-Pt(C6F5)(2)(PPh3)(mu(3)-1 kappa C-alpha:2 kappa C-beta:3 kappa N-C2C5H4N-2)}{Pt-3(C6F5)(2)(mu(3)-3 kappa C-alpha:eta(alpha, )beta(2):2 kappa N-CH=HC5H4N-2)(PPh3)(2)}] (3). Complex 3, characterized cr ystallographically, can be described as a formal zwitterionic cationic Pts cluster-substituted alkynyl platinate complex [Pt](-)-C equivalent to CC5H4 N-2[Pt-3](+) (3A), rather distorted. Another important feature in 3 is the presence of a vinyl group capping the Pta framework. Treatment of 2 with th e equimolar amount of PPh3 allows the synthesis not only of 5 but also of t he less polar isomeric complex [trans,cis(PPh3)(2)(H)Pt(mu-1 kappa C-alpha: 2 kappa N-C equivalent to CC5H4N-2)Pt(C6F5)(2)(PPh3)] (4).