Syntheses and Second-Order Optical Nonlinearity of Ruthenium σ-Acetylides with an End-Capping Organic Electron Acceptor and Thienyl Entity in the Conjugation Chain

Abstract

Ruthenium σ-acetylides with an end-capping organic electron acceptor and thienyl entity in the conjugation chain, Ru(C⋮CY)(PPh3)2(η5-C5H5) (Y = th-CHO, th-CHC(CN)2, th-(E)-CHCH-th-CHO, th-(E)-CHCH-th-CHC(CN)2, C6H4-(E)-CHCH-th-NO2, th-(E)-CHCHC6H4-4-NO2, C6H4C⋮C-th-NO2, th-(E)-CHCH-th-CHCHC6H4-4-NO2, C6H4NC(H)-th-NO2, th-(E)-CHCHC5H4N+Me, th-C⋮CC5H4N+Me, th-(E)-CHCH-th-NO2, th-C⋮C-th-NO2) (th = 2,5-disubstituted thiophene), were synthesized. These complexes exhibit intense charge transfer from the ruthenium donor to the organic acceptor. The quadratic hyperpolarizabilities of the selected complexes were determined using the hyper Rayleigh scattering method. Single-crystal X-ray analysis was employed to examine the structures of Ru(C⋮CC6H4-(E)-CHCH-th-NO2)(PPh3)2(η5-C5H5) and Ru(C⋮C-th-CHC(CN)2)(PPh3)2(η5-C5H5).