Naslov
Structural and vibrational properties of tetraoxaporphyrin dication, the oxygen analogue of porphyrin, and of isoelectronic diprotonated porphyrin

Autori
Jelovica, Ivana ; Moroni, Laura ; Gellini, Cristina ; Salvi, Pier Remigio ; Orlić, Nada

Izvornik
Journal of Physical Chemistry A (1089-5639) 109 (2005), 44; 9935-9944

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
free-base porphin; density-functional calculations; electronic-absorption-spectrum; resonance raman-spectroscopy; infrared-spectra; ground-state; force-field; flexibility; intensities; anthracene

Sažetak
Structural calculations by means of the density functional method have been performed on tetraoxaporphyrin dication and on isoelectronic diprotonated porphyrin as well as on the sulfur and carbon analogues of porphyrin. A detailed study of the stable conformations of these compounds is reported starting with the most symmetrical conformations and lowering the symmetry along the vibrational coordinates with imaginary frequency. The calculated geometries are related to experimental structures available from X-ray diffraction studies. The Raman spectra of tetraoxaporphyrin dication exciting with micro-Raman instrumentation at 785 nm and of diprotonated porphyrin in near-resonance conditions with the Soret band have been measured. The correlation between frequencies calculated with the DF/B3-LYP/cc-pVDZ procedure for porphyrin, diprotonated porphyrin, and tetraoxaporphyrin dication has allowed for making a vibrational assignment for the latter two systems in excellent agreement with experiment using a single frequency scale factor.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

POVEZANOST RADA