Dimerization of zinc tetrasulfophthalocyanine in sol–gel process

The issue of dimerization is vital in determining the optical properties of dye-doped sol–gel materials and metallophthalocyanine offers an excellent opportunity to characterize dimmers from monomers because of their identified absorption bands. In this paper, zinc tetrasulfophthalocyanine (ZnTSPc) was encapsulated in silica–xerogel matrix by sol–gel technique. Dimerization of ZnTSPc was studied using UV–Vis optical absorption spectra, correlated with various stages of the sol–gel process. The results show that in the composites ZnTSPc concurrence in forms of monomer and dimmer, and dimerization behaves differently in the sol, gel and xerogel stages. Reasons are given from the change of the microenvironment of the composites in which ZnTSPc existed.