A salt metathesis route to ruthenium carbene complex isomers with pyridine dicarboxamide-derived chelate pincer ligands

Abstract

Reaction of the doubly deprotonated pyridine 2,6-dicarboxamido ligand (1) with (PCy3)2Cl2 Ru=CHPh (3a) in THF gave a mixture of (Hg)(PCy3)Ru=CHPh isomers (4). The pentane soluble N,N,O-4 isomer was isolated by extraction and characterized by X-ray diffraction. The O,N, O-4 isomer was identified in the residue. Single crystals of the closely related complex (Hg)(NHC) Ru=CHPh, O,N,O-5, were obtained from the reaction of 1 with (NHC)(PCy3)Cl2Ru=CHPh (3b) and used for the X-ray crystal structure analysis of the system. © 2007 Verlag der Zeitschrift für Naturforschung.