Hemilabile Properties of the η3-Diphenylvinylphosphine (DPVP) Phosphaallyl Ligand: Synthesis and Reactions of [(η5-C5Me5)Ru(η3-DPVP)(η1-DPVP)]PF6

Pentamethylcyclopentadienyl-ruthenium(II) half-sandwich complexes containing the olefinic phosphine ligand diphenylvinylphosphine (DPVP) are described. The hemilabile properties of the η 3 -DPVP ligand, a neutral monometallic phosphaallyl, are illustrated by reactions with carbon monoxide and terminal acetylenes. DPVP reacts with [(η 5 -C 5 Me 5 )RuCl 2 ] 2 to give the disubstituted ruthenium(II) compound [(η 5 -C 5 Me 5 )Ru(η 3 -DPVP)(η 1 -DPVP)]PF 6 ( 1 ). 1 reacts with NaNCS to form [(η 5 -C 5 Me 5 )Ru(η 1 -DPVP) 2 (NCS)] ( 2 ). 1 reacts with CO, HC⋮CPh, HC⋮CCH 2 CH 2 OH, and HC⋮CCH 2 OH to form [(η 5 -C 5 Me 5 )Ru(η 1 -DPVP) 2 (CO)]PF 6 ( 3 ), [(η 5 -C 5 Me 5 )Ru(η 1 -DPVP) 2 {C C(H)(Ph)}]PF 6 ( 4 ), [(η 5 -C 5 Me 5 )Ru(η 1 -DPVP) 2 {C(CH 2 ) 3 O}]PF 6 ( 5 ), and [(η 5 -C 5 Me 5 )Ru(η 1 -DPVP) 2 {C C(H)(CH 2 OH)}]PF 6 ( 6 ), respectively. 6 slowly decomposes in aerated solutions to form 3, presumably through an allenylidene intermediate. 6 reacts with excess DPVP and HPF 6 to form the novel, P,P -diphenyltrihydrophospholonium vinylidene compound [(η 5 -C 5 Me 5 )Ru(η 1 -DPVP) 2 {C C(CH 2 ) 2 PPh 2 CH 2 }][PF 6 ] 2 ( 7 ). The characteristic 1 H, 13 C{ 1 H}, and 31 P{ 1 H} spectroscopic features of all compounds are described. The molecular structures of compounds 1, 4, 5, and 7 have been determined by single crystal X-ray crystallography.