Theoretical investigation of the molecular, electronic structures and vibrational spectra of a series of first transition metal phthalocyanines.

Abstract A theoretical investigation of the fully optimized geometries and electronic structures of metallophthalocyanines FePc, CoPc, NiPc, CuPc and ZnPc has been conducted with the density functional theory (DFT) method. A comparison between the different molecules for the geometry, molecular orbital, and atomic charge is made. The simulated order of the sizes of the central hole is FePc > CoPc > NiPc   NiPc > CuPc > ZnPc, and the atomic charges of the central metal (M = Fe, Co, Ni, Cu, Zn) ions vary in the same order, FePc > CoPc > NiPc  −1 for FePc, CoPc, NiPc, CuPc and ZnPc in IR spectra show the order of NiPc > CoPc > FePc > CuPc > ZnPc, and the corresponding peaks predicted at 894, 896, 898, 882 and 871 cm −1 , respectively, also exhibit the same order as above-mentioned. Moreover, the lines of fit through plots of the experimental IR and Ra frequencies versus the calculated ones show very good correlations.