Raman Spectroscopy on Free-Base Meso-tetra(4-pyridyl) Porphyrin under Conditions of Low Temperature and High Hydrostatic Pressure.

Autor: Dos Reis JRT; Graduate Program in Physics, Institute of Natural Sciences, Federal University of Pará, Belém 66075-110, PA, Brazil., Leite FF; Graduate Program in Physics, Institute of Natural Sciences, Federal University of Pará, Belém 66075-110, PA, Brazil.; Department of Exact and Technological Sciences, Federal University of Amapá, Macapá 68903-419, AP, Brazil., Sharma K; Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487, USA., Ribeiro GAS; Department of Physics, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil., Silva WHN; Department of Physics, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil., Batista AA; Departament of Chemistry, Federal University of São Carlos, São Carlos 13565-905, SP, Brazil., Paschoal AR; Department of Physics, Federal University of Ceara, Fortaleza 60455-760, CE, Brazil., Paraguassu W; Graduate Program in Physics, Institute of Natural Sciences, Federal University of Pará, Belém 66075-110, PA, Brazil., Mazzoni M; Department of Physics, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil., Barbosa Neto NM; Graduate Program in Physics, Institute of Natural Sciences, Federal University of Pará, Belém 66075-110, PA, Brazil., Araujo PT; Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487, USA.
Jazyk: angličtina
Zdroj: Molecules (Basel, Switzerland) [Molecules] 2024 May 17; Vol. 29 (10). Date of Electronic Publication: 2024 May 17.
DOI: 10.3390/molecules29102362
Abstrakt: We present a Raman spectroscopy study of the vibrational properties of free-base meso-tetra(4-pyridyl) porphyrin polycrystals under various temperature and hydrostatic pressure conditions. The combination of experimental results and Density Functional Theory (DFT) calculations allows us to assign most of the observed Raman bands. The modifications in the Raman spectra when excited with 488 nm and 532 nm laser lights indicate that a resonance effect in the Qy band is taking place. The pressure-dependent results show that the resonance conditions change with increasing pressure, probably due to the shift of the electronic transitions. The temperature-dependent results show that the relative intensities of the Raman modes change at low temperatures, while no frequency shifts are observed. The experimental and theoretical analysis presented here suggest that these molecules are well represented by the C2v point symmetry group.
Databáze: MEDLINE
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