Organometallic complexes for nonlinear optics VI: syntheses of rigid-rod ruthenium σ-acetylide complexes bearing strong acceptor ligands; X-ray crystal structures of trans-[Ru(C  CC 6H 4NO 2-4) 2(dppm) 2] and trans-[Ru(CCC 6H 4C 6H 4NO 2-4,4′) 2(dpppm) 2

Abstract

A series of systematically-varied ‘rigid-rod’ octahedral ruthenium acetylide complexes, bearing the strong acceptor substituent -NO 2, of general formula rans-[Ru(C  CC 6H 4R-4) 2(dppm) 2] (R  NO 2, C 6H 4NO 2-4, C 6H 4CHCHC 4CHCHC 6H 4NO 2-4, ( E) has been synthesized. X-ray structural studies of trans-[Ru(CCC 6H 4R-4) 2(dppm) 2] (RNO 2. C 6H 4NO 2-4) confirm the trans-disposed geometry of the acetylide ligands and, for the latter, non-planarity of the biphenylene groups. The mixed acetylide ‘rigid-rod’ complex trans-[Ru(C  CPh)(CCC 6H 4NO 2-4)(dppm) 2] has also been prepared. Semiempirical calculations employing zindo were performed on the mixed-acetylide complex, the results suggesting that the effect of trans-disposed ligands on the molecular quadratic hyperpolarizability β is not additive.