Density functional study of trans,trans,trans-[Pt(N3)2(OH)2(Py)2] on molecular structure and vibrational spectroscopy.

This study records the selection of the best combination of geometric optimization and frequency calculation methods of the trans,trans,trans-[Pt(N3)2(OH)2(py)2](FM-190) by using different density functional calculation methods and basis sets. The results show that the CAM-B3LYP/SDD method has the best fit to the experimental data for geometric optimization, while the LSDA/SDD method has better performance in frequency calculation, and the infrared vibration peak is assigned. In addition, the calculated HOMO and LUMO show the energy gap and the internal charge transfer of this complex. The hyperconjugation of the pyridine ring have been explained by NBO analysis.