Synthesis of (Indenylidene)phosphoranes - A Novel Class of Ligand Precursors for Main-Group and Transition Metal Organometallics

摘要

IndPPh_2 (1) reacts with RCH_2Br to form the phosphonium salts [RCH_2P(Ph)_2Ind]~+Br~- (2:R = Ph;3:R = C_6F_5) in high yields.Oxidation of 1 with H_2O_2 in THF proceeds smoothly to give the phosphane oxide mdP(O)Ph_2 (4).Dehydrobromin-ation of 2 and 3 with NaH in THF yields the corresponding indenylidenephosphoranes C_9H_6=P(Ph)_2CH_2R (5:R = Ph;6:R = C_6F_5).Further deprotonation of 6 with excess NaH results in formation of sodium l-j[(pentafluorophenyl)methylidene] diphenylphosphoranyl|indenide (7),isolated as a solvate with three THF molecules.A detailed NMR study of new li-gand precursors and X-ray structure studies of 5 and 7 have been accomplished.A short F->Na coordination contact in the molecular structure of 7 has been detected.