Autor: V. S. Chirvonyi, Pierre-Yves Turpin, Sergei N. Terekhov
Rok vydání: 2000
Předmět:
Zdroj: Journal of Applied Spectroscopy. 67:796-805
ISSN: 0021-9037
DOI: 10.1023/a:1004199313485
Popis: The resonance Raman scattering (RS) spectra of a series of nitro-substituted derivatives of the free base of tetraphenyl porphyrin that were obtained on continuous excitation near the Soret band have been investigated. For the molecules in which the NO2 group is located in the β-position of pyrrole rings or in the para-position of meso-phenyl substituents, an intense line of the mode within the range 1340–1355 cm−1 is discovered. Based on the obtained resonance RS spectra of the diprotonated derivatives of nitro-tetraarylporphyrins, it is assigned to symmetrical vibration of a nitro group (ν s NO2). Activation of the ν s NO2 vibration is indicative of the existence of the π-delocalization effect for a number of nitro-substituted porphyrins at which interaction between the molecular orbitals of the nitro-substituents and the porphyrin macrocycle occurs. Moreover, the π-delocalization is typical of both direct addition of a nitro-substituent to the porphyrin ring and of its binding via a meso-phenyl group. The results obtained demonstrate the informative value of the resonance RS spectroscopy for creating and studying model donor–acceptor systems with the participation of porphyrins.
Databáze: OpenAIRE
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