PHOTOINDUCED ELECTRON-TRANSFER IN MOLECULAR ORGANIZATES AT THE GAS WATER INTERFACE

The influence of the molecular geometry is of fundamental importance f or a better understanding of the photoinduced electron transfer mechan ism. Because of their typical molecular structures, cyclophane rings h ave proved to be suitable for this purpose as electron acceptor molecu les adsorbed under an amphiphile monolayer. We used a pyrene-labelled phospholipid derivative both as molecular anchor for the cyclophane ri ng and electron donor molecule. The co-spreading technique was used to prepare the complex monolayers. Surface pressure and surface potentia l measurements have indicated similar monolayer behaviour as with dimy ristoylphosphatidic acid as anchor molecule, leading to the same paral lel orientation of the molecular plane of the cyclophane ring with res pect to the water surface. Surface reflection has revealed a change in orientation of the pyrene moiety during compression, but no relevant dimer formation was observed. Fluorescence spectra were almost of exci mer emission nature only. Steady state fluorescence quenching of the p yrene depends on the pyrene/cyclophane co-spreading ratio.