Theoretical study of the structure, vibrational spectra, and electronic spectra of oxotitanium porphyrin, octamethylporphyrin, porphyrazine, and phthalocyanine complexes

The molecular structures, vibrational spectra, and electronic spectra of oxotitanium porphyrin, octamethylporphyrin, porphyrazine, and phthalocyanine have been studied by density functional theory and time-dependent density functional theory calculations utilizing B3LYP method and triple-ζ valence basis sets. All four molecules have the equilibrium structures of C4v symmetry with convex macrocycles. In all cases titanium atom is out of plane of four central nitrogen atoms, forming a square pyramid with them. The Ti-O distances are equal to 1.614, 1.617, 1.620, and 1.617 Å and the Ti-N distances are 2.125, 2.125, 2.074, and 2.087 Å (oxotitanium porphyrin, octamethylporphyrin, porphyrazine, and phthalocyanine, respectively).