ELECTRON-TRANSFER BETWEEN PHOTOEXCITED OXACYANINE DYE AND DITHIOCARBAMATE IN LB FILMS - COUNTERION AND PH-DEPENDENCE

We have investigated the electron transfer between photoexcited diocta decyl-oxacyanine perchlorate S9 and dioctadecyldithiocarbamate incorpo rated in mixed monolayers both at the air/water interface and in trans ferred Langmuir-Blodgett films with the functional head groups in cont act with an aqueous phase. The fluorescence of S9 in the mixed films a t the air/water interface and in the transferred films was measured as a function of the concentration of different alkali metal ions or pH. Electron transfer from the thiocarbamate group to the excited S9 resu lts in fluorescence quenching of the oxacyanine dye. The degree of flu orescence quenching has been found to depend on pH and on the concentr ation and nature of the cation in the subphase.