Effect of Pyridine on the Structure and Vibrations of Cobalt Phthalocyanine

Abstract Effect of pyridine on cobalt phthalocyanine (CoPc) has been studied by the density functional theory and Raman spectroscopy. Thermal evaporation method has been used for the preparation of a thin film of CoPc and then Raman spectra of CoPc film have been recorded with and without exposure of pyridine. The molecular structure of CoPc and its coordinated complexes with pyridine have been computed using B3LYP/6-31(d,p) level of density functional theory calculations by employing Gaussian program package. Calculations show some in-plane and out-of-plane distortions in the structure of CoPc. Some noticeable changes have been observed in the Raman spectrum of CoPc thin film after its exposure with pyridine. Changes in wavenumbers and relative intensities of some of the bands have been observed. Most of the observed bands show downward shifts in the wavenumbers. These changes, are attributed to the weakening of some bonds and change of symmetry of CoPc, and confirm the coordination of pyridine molecule(s) with CoPc molecule