SPECTROSCOPIC AND PHYSICOCHEMICAL PROPERTIES OF RARE-EARTH PHTHALOCYANINES ENTRAPPED IN SOL-GEL GLASSES

The electronic absorption spectra of samarium and neodymium phthalocya nines in DMSO and entrapped in glasses obtained via the sol-gel techni que have been obtained. Decrease in concentration of metallophtalocyan ines in DMSO leads to observed changes in the relative intensifies of the two bands in the Q-band region. This behavior could be explained b y the shifts in equilibrium between the LnPc(2) and LnPc(+) forms, cau sed by the dilution. In view of this interpretation, the entrapment of the metallophthalocyanines in the sol-gel glass matrices shifts the d iphthalocyanine <-> monophthalocyanine equilibrium towards the monopht halocyanine (LnPc(+)) form. (C) 1997 Elsevier Science B.V.