Neutral and cationic diphenylphosphine and diphenylphosphido derivatives of a trinuclear ruthenium carbonyl cluster containing a bridging 1-azavinylidene ligand

The synthesis and some reactivity of a number of neutral and cationic diphenylphosphine and/or diphenylphosphido derivatives of the 1-azavinylidene cluster compound [Ru-3(mu-H)(mu-N=CPh2)(CO)(10)] (1) are described. Compound 1 reacts with diphenylphosphine to give the substituted derivative [Ru-3(mu-H)(mu-N=CPh2)(PPh2H)(CO)(9)] (2). Thermolysis of compound 2 leads to the dihydrido-mu-phosphido derivative [Ru-3(mu-H)(2)(mu-N=CPh2)(mu-PPh2)(CO)(8)] (3), which on exposure to carbon monoxide is converted into the non-hydridic derivative [Ru-3(mu-N=CPh2)(mu-PPh2)(CO)(9)] (4). Treatment of complex 3 with diphenylphosphine gives [Ru-3(mu-H)(2)(mu-N=CPh2)(mu-PPh2)(PPh2H)(CO)(7)] (5). Compounds 2, 4, and 5 undergo protonation with HBF4 . OEt2 to give the cationic derivatives [Ru-3(mu-H)(2)(mu-N=CPh2)(PPh2H)(CO)(9)][BF4] (8), [Ru-3(mu-H)(mu-N=CPh2)(mu-PPh2)(CO)(9)][BF4] (9), and [Ru-3(mu-H)(3)(mu-N=CPh2)(mu-PPh2)(PPh2H)(CO)(7)][BF4] (10), respectively. The syntheses of these cationic complexes represent rare examples in which the protonation of neutral phosphido-bridged compounds has been achieved. (C) 1997 Elsevier Science S.A.