Effect of fluorosubstitution and central metals on the molecular structure and vibrational spectra of metal phthalocyanines

Abstract

In this work, the effect of fluorosubstitution in metal phthalocyanines (MPc) on their molecular structure and vibrational spectra is studied. For this purpose, the IR- and Raman spectra of unsubstituted (FePc), tetrafluorosubstituted (FePcF4) and hexadecafluorosubstituted iron phthalocyanines as well as isotopic wavenumber shifts upon 15N substitution in FePc and FePcF4 were investigated experimentally and theoretically. The calculated geometries of molecules were compared with the experimental crystallographic data obtained by the single crystal structure refinement. The density functional theory (DFT) calculations were used for the analysis of IR- and Raman spectra of these three derivatives. Several groups of vibrations most sensitive to fluorosubstitution have been revealed. Apart from the influence of F-substitution, the effect of different central metal ions (M = Cu, Co, Zn, Fe, Pd, VO, Pb) on the structure and vibrational spectra of MPc, MPcF4 and MPcF16 is also discussed.