The molecular, electronic structures and IR and Raman spectra of metal-free, N,N′-dideuterio, and magnesium tetra-2,3-pyrazino-porphyrazines: Density functional calculations

A theoretical investigation of the fully optimized geometries and electronic structures of the metal-free (TPyPzH₂), N,N′-dideuterio (TPyPzD₂), and magnesium (TPyPzMg) tetra-2,3-pyrazino-porphyrazine has been conducted based on density functional theory. The optimized geometries at density functional theory level for these compounds are reported here for the first time. A comparison among the different molecules, including tetra-2,3-pyridino-porphyrazine (TPdPzH₂), phthalocyanine (H₂Pc) compounds, for the geometry, molecular orbital, and atomic charge is made. The substituent effect of the N atoms on these properties of these compounds is discussed. The IR and Raman frequencies and intensities for the three compounds have also been calculated at density functional B3LYP level using the 6-31G(d) basis set. Detailed assignments of the N-H, N-M, and pyrazine ring vibrational bands in the IR and Raman spectra have been made based on assistance of animated pictures. The isotope effect of D atoms are also discussed.