Insight into the Reaction of a Dinuclear Phosphinidene Complex with Nitriles.

The phosphinidene complex [Cp*P{W(CO)5}2] (1; Cp*=C5 Me5 ) reacted with malononitrile to give the 1,2-dihydro-1,3,2-diazaphosphinine derivative 2. The reaction of 1 with 1,4-benzodinitrile gave [1,4-{{W(CO)5}2 P-N=C(Cp*)}2 (C6 H4)] (3), the first example of a cumulene-like aminophosphinidene complex. The reaction of 1 with aniline gave the aminophosphinidene complex [(Ph)N(H)P{W(CO)5}2] (4). To compare the reactivity of benzonitrile and aniline with 1, the phosphinidene complex 1 was reacted with three different isomers of aminobenzonitrile (2-, 3-, and 4-aminobenzonitrile). These reactions gave an insight into the reaction pathway of 1 with benzonitrile derivatives. Compounds 5, 6 a, 6 b, and 7, which are derivatives of 1,2-dihydro-1,3,2-diazaphosphinine or benzo-2H-1,2-azaphospholes, were, as well as all other products, characterized by mass spectrometry, NMR and IR spectroscopy, and X-ray structure analysis.