Electronic states and infrared spectroscopy of Ni- and Co-phthalocyanines: neutral and oxidized forms

Abstract

Quantum chemical calculations reproduced the experimental infrared spectra of NiPc , NiPc ( AsF 6)0.5, CoPc , and CoPc ( AsF 6)0.5. The agreement in the changes of line intensities supports the ligand-centered oxidation in both NiPc ( AsF 6)0.5 and CoPc ( AsF 6)0.5. Whereas, electron configurations of NiPc and NiPc + as well as CoPc represent standard cases, i.e. they can be taken as a closed-shell and open-shell system, respectively, the electron configuration of CoPc + must be taken as an open-shell system (while the number of electrons is even) to get an agreement of theoretical and experimental infrared spectra.