PHTHALOCYANINES BOUND TO INSOLUBLE POLYSTYRENE - SYNTHESIS AND PROPERTIES AS ENERGY-TRANSFER PHOTOSENSITIZERS

Metallotetracarboxyphthalocyanines (MTCPc, M = Cu, Al) were bound to t he amino groups of Amberlite IRA-93 by amide bonding. The insoluble ma terials obtained were characterized by IR absorption, visible absorpti on and diffuse reflectance, and ICP atomic emission spectroscopy, and tested for energy transfer under irradiation in the phthalocyanine Q-b and. Samples containing AlTCPc are strongly fluorescent both in the so lid state and in DMF suspension. Fluorescence quantum yields decrease sharply in toluene suspension. In the solid state, fluorescence may be quantitatively quenched by energy-transfer to an adsorbed dye. Single t molecular oxygen (O-1(2)) quantum yields were obtained in suspension by monitoring the photooxidation of diphenylisobenzofuran. Values are drastically reduced in DMF suspension and even more in toluene suspen sion relative to homogeneous solution. This fact is attributed to dye aggregation (M = Cu) and excited-state self-quenching (M = Al). Result s can be rationalized by assuming that MTCPc incorporation occurs main ly at the polymer surface and that dye-to-dye interaction in suspensio n depends strongly on the environment. (C) 1997 Elsevier Science S.A.