Molecular structure, electronic structure and vibrational spectra of metal-free, N,N′-dideuterio, and magnesium tetrakis(thiadiazole)porphyrazines: Density functional calculations

A theoretical investigation of the fully optimized geometries and electronic structures of the metal-free (TTDPzH2), N,N′-dideuterio (TTDPzD2), and magnesium (TTDPzMg) tetrakis(thiadiazole)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 between different molecules for the geometry, molecular orbital and atomic charge is made and the substituent effect of the thiadiazole annulation on the molecular structure of these compounds is discussed. The infrared frequencies and intensities for these three compounds have also been calculated at density functional B3LYP level using the 6-31G(d) basis set. Detailed assignments of the N-H and N-M vibrational bands in the IR spectra have been made on the basis of comparison between the calculated data and the experimental results.