Fluorocarbon ruthenium complexes

Abstract

Hexafluoroacetone and 1,1-dicyano-2,2-bis(trifluoromethyl)ethylene both displace carbon monoxide from the ruthenium(0) complex (CO)₃[EtC(CH₂O)₃P]₂Ru to form (CO)₂[EtC(CH₂O)₃P]₂Ru[(CF₃)₂CO] and (CO)₂[EtC(CH₂O)₃P]₂Ru[(CF₃)₂CC(CN)₂] respectively, in which the CO ligands occupy a relative trans-configuration. The latter complex rapidly isomerises in solution; one phosphite ligand exchanging co-ordination positions with a CO. A similar reaction occurs with trans-1,2-dicyano-1,2-bis(trifluoromethyl)ethylene forming (CO)₂[EtC(CH₂O)₃P]₂Ru[CF₃(CN)CC(CF₃)CN], in which the olefin retains its original stereochemistry. Tetrafluoroethylene reacts with (CO)₃L₂Ru [L =(MeO)₃P, (EtO)₃P, or EtC(CH₂O)₃P] to form the corresponding complexes (CO)₂L₂Ru(C₂F₄) where the CO ligands occupy a relative trans-configuration. The bonding and stereochemistry of the complexes is discussed in the light of the infrared, and ¹H and ¹⁹F n.m.r. spectroscopic data. The mechanism of formation of complexes of this type is discussed.