Reaction of double ylide C(PPh_3)_2 with [W(CO) _6] - Crystal structures of [(CO)_5W(CCPPh_3)] and [(CO)_5W{n~1-O_2C_2(PPh3)2}] and bonding analyses of TM(CCPR_3)I compounds

摘要

The photochemically generated complex [(CO)_5W(thf)] reacts with C(PPh_3)_2 (1) to provide the salt (HC{PPh_3} _2)_2[W2(CO)_(10)] (5) in high yield by abstraction of a proton from the solvent thf. With [W(CO)_6], a slow reaction in benzene occurs to give a mixture of [(CO)_5W{O _2C_2(PPh_3)_2}] (6) and the heterocumulene (phosphonioacetyllde) complex [(CO)_5W(CCPPh _3)l (7) by a Wittig type reaction. Both compounds were characterized by spectroscopic and. X-ray diffraction analyses. Theoretical density functional calculations reveal that the ligand CCPPh_3 in 7 and in similar complexes is a strong a-donor but weak it-acceptor.