K-EDGE EXAFS SPECTRA OF COPPER POLYPHTHALOCYANINES

High-resolution experimental K-edge extended X-ray absorption fine structure (EXAFS) spectra of copper phthalocyanine and poly(phthalocyanines) were measured. New experimental data concerning the electronic structure of these compounds and the effect of polymerization on the electron energy state of the central metal atom have been derived. The polymerization produces delocalization and redistribution of the electron density, which modifies the electron state of the central metal atom. In particular, the electron density on the copper atom in a polymer based on the pyromellitic acid is 0.09 a.u. higher than in the monomer. The experimental EXAFS spectra show the system of bonds in copper phthalocyanine to possess a high degree of conjugation. The remote acceptor Cl substituents significantly affect the electronic state of the central metal atom and the chelate node of phthalocyanine, and hence, alter the X-rav absorption spectra. Upon substituting R = Cl at the periphery of the CuPhcCl16 molecule, the electron density on the central copper atom decreases by 0.16 a.u.