The Effect of the Axial Ligation of Pyridine on the UV-VIS and Resonance Raman Spectra of Metalloporphyrins

The effect of the axial ligation of pyridine（Py） on the UV-VIS spectra and the resonance Raman（RR） spectra of Co（Ⅱ）, Ni（Ⅱ）,Cu（Ⅱ） Zn（Ⅱ） and Cd（Ⅱ） protoporphyrin Ⅸ dimethyl ester（PP） complexes are studied. The experimental results are elucidated based on the interactions among the axial ligand Py, central ion and the porphyrin ring: Py reacts, directly, or through the metal ions, with the porphyrin ring, effects the energy of the orbitals of the ring or the force constants of the ring skeletal bonds,thus results in the wavelength shifts in the UV-VIS absorption bands and the frequency displacements in the RR structure-sensitive bands of the pyridinated complexes.