A simple, novel method for the preparation of polymer-tetherable, zwitterionic merocyanine NLO-chromophores

A suite of polymer-ready nonlinear optical merocyanines has been synthesised and characterised. The tethering functionality-a vicinal dihydroxypropyl residue-is introduced onto the donor nitrogen of the chromophore precursor without the need for protection/deprotection steps, thereby giving ready access to potentially high T-g condensation polymer systems. An X-ray crystal structure determination on a representative chromophore 5 confirms the largely zwitterionic nature of these systems and experimental measurements of second-order nonlinear response [beta (0)], by hyper-Raleigh scattering, indicate that a pyridylidene donor-quinomethide acceptor combination gives rise to the largest nonlinearity.