Theoretical and spectroscopic study of nickel(II) porphyrin derivatives

Berríos C.; Cardenas-Jiron, GI; Marco, JF; Gutierrez C.; Ureta-Zanartu, MS

Abstract

A set of substituted (sulfonate, amino) nickel porphyrin derivatives such as phthalocyanine and phenylporphyrin was studied by spectroscopic (UV-vis, FTIR, XPS) and quantum-chemical methods. The Q and Soret bands were identified in the UV-vis spectra of aquo solutions of the tetrasulfo-substituted complexes and in DMF and ACN solutions of the amino-substituted phenylporphyrin and phthalocyanine Ni(II) complexes, respectively. In all the complexes the frontier molecular orbitals predict that the oxidation and reduction sites are localized on the ligand rather than in the metal atom. A natural bonding orbital (NBO) analysis of all the complexes showed that a two-center bond NBO between the pyrrolic nitrogens (Npyrr) and the nickel atom does not exist, the Npyrr·Ni interaction occurring instead by a delocalization from one lone pair of each Npyrr toward one lone pair of the nickel atom, as estimated by second-order perturbation theory. The calculated values of electronic transitions between the frontier molecular orbitals are in good agreeement with the UV-vis data. At the theoretical level, we found that while the ligand effect is more important in the Q-band (∼16 kcal/mol), the substituent effect is more significant in the Soret band (∼9 kcal/mol). A good agreement was also found between the experimental and calculated infrared spectra, which allowed the assignment of many experimental bands. The XPS results indicate that the Ni(II) present in the phenylporphyrin structure is not affected by a change of the substituent (sulfonate or amino). © 2007 American Chemical Society.

Más información

Título según WOS: Theoretical and spectroscopic study of nickel(II) porphyrin derivatives
Título según SCOPUS: Theoretical and spectroscopic study of nickel(II) porphyrin derivatives
Título de la Revista: JOURNAL OF PHYSICAL CHEMISTRY A
Volumen: 111
Número: 14
Editorial: AMER CHEMICAL SOC
Fecha de publicación: 2007
Página de inicio: 2706
Página final: 2714
Idioma: English
URL: http://pubs.acs.org/doi/abs/10.1021/jp0653961
DOI:

10.1021/jp0653961

Notas: ISI, SCOPUS