A Study of Some Novel Metal-chelated and Bromizated Phthalocyanine Dyes in Relation to Their Photo-physical Properties

Several kinds of novel tetra-substituted metal phthalocyanines have been synthesized, based on the precursor of 3-(2,4-ditert-pentylphenoxy)phthalonitrile. The central metals include lead, zinc, copper, nickel, manganese, cobalt and magnesium. These compounds are characterized by elemental analysis, UV-Vis, IR and 1H-NMR. Some of them are selected to be further subjected to bromization. Through experiments, we draw the conclusion that metalation of these phthalocyanines can influence their absorption wavelengths greatly. Most of the metal phthalocyanines are blue-shifted compared to that of free phthalocyanine. The film photo-absorption behavior is also investigated by spin-coating with n-butyl ether and the results show that there is a slight increase of absorption wavelength and the broadening of absorption bands. Under proper conditions, reacting some of these dyes with bromine can produce to a certain extent, bathochromic effect. The absorption wavelength of some of the bromizated compounds is very close to that of laser used in the information technology. An attempt is made to correlate the structures of the metal-centred and bromizated α-(2,4-ditert-pentylphenoxy) phthalocyanines with their photo-physical properties. The nature of the effects of the substitution, central metals and bromization on Q-band absorption of these dyes are presented and discussed.