Spectral and photophysical properties of zinc(II) complexes with alkylsubstituted derivatives of dipyrrolylmethene and their resistance to protolytic dissociation and photochemical destruction

Autor: Evgeniy V. Rumyantsev, Yu. S. Marfin, S. N. Aleshin
Rok vydání: 2013
Předmět:
Zdroj: Russian Journal of Physical Chemistry A. 87:323-328
ISSN: 1531-863X
0036-0244
DOI: 10.1134/s003602441302026x
Popis: The spectral and photophysical properties of zinc(II) complexes with alkylsubstituted derivatives of dipyrrolylmethene, along with the kinetics of their protolytic dissociation and photochemical degradation in organic solvents of different natures, are studied by means of electronic absorption and fluorescence spec� troscopy. It is found that protic solvents have the strongest effect on absorption spectra, while electron donors affect fluorescence spectra due to differences in the mechanisms of solvation for the ground and excited states of molecules. It is shown that the reaction product of the protolytic dissociation of complexes in benzene solutions of acetic acid is a protonated form of ligand. The observable and genuine rate constants of dissoci� ation reactions are determined and activation parameters are calculated. A kinetic model of the process is proposed, and the regularities of the effect the nature of ligand has on the kinetics of dissociation are estab� lished. The photochemical degradation of compounds proceeds on monopyrrole products, the photolysis rate falls as the a degree of alkylation increases, and the nature of the substituent in the β�position of the ligand's pyrrole ring has a greater effect on the stability of a compound.
Databáze: OpenAIRE
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