<title>Photochemistry and photophysics of stilbene and diphenylpolyene surfactants in supported multilayer films</title>

Abstract

A number of surfactant trans-stilbene derivatives have been synthesized and investigated in supported Langmuir-Blodgett assemblies. Layers of pure stilbene surfactants or mixtures with fatty acids show 'H' aggregate characteristics including relatively low oscillator strengths for the lowest excited singlet state. Consequently these exhibit relatively low ability, individually, to donate excitation energy or transfer electrons over long ranges. Mixtures of these stilbenes, layered together to form mixed films, also show 'H' aggregate characteristics but give evidence for delocalization which can effectively span the width of an entire monolayer and result in efficient energy and electron transfer processes over distances spanning several monolayers. The extension to 'H' aggregated and dilute (monomer) diphenylbutadiene and diphenylhexatriene layers results in assemblies in which vectorial energy transfer and redox processes can occur. One of the molecules used as an energy transfer and electron transfer quencher is the cobalt (III) complex of 8S1A. Although this molecule undergoes photochemical intramolecular-electron transfer-induced fragmentation in solution and microheterogeneous media, it show net photostability in the films but serves a highly effective trap.