Syntheses and molecular structures of trans-bis(alkynyl) tetrakis-triethylphosphite ruthenium complexes

Abstract

A simple synthesis of complexes trans-[Ru(C≡CC6H4-4-R)2{P(OEt)3}4] from trans-[RuCl2{P(OEt)3}4] and the terminal alkyne is described. Crystallographically determined molecular structures indicate a range of conformers, with the ethynyl arylene rings differing in their orientation with respect to each other across the Ru{P(OEt)3}4 fragment. Electrochemical analysis reveals a well-behaved one-electron oxidation process, which is only some 100 mV more positive that the analogous trans-[Ru(C≡CC6H4-4-R)2(dppe)2] complexes. Quantum chemical calculations reveal largely delocalised electronic structures and suggest that these compounds may find use as wire-like molecules within single molecule electronics.