The X-Ray crystal and molecular structures of the 4-pyrazol derivatives 3-methyl-4-diazo-5-benzamido-IH-pyrazole (4) and 3-benzamido-5-methyl-IHpyrazole (3) have been determined. A dimeric structure has been found for the first and polymeric for the second. A comparison of 4 with 1,3-dimethyl-4-diazo5-benzamido-1H-pyrazole (2) shows differences in the geometrical parameters of the pyrazole ring due to electron delocalization in 2 consequent to the nitrogen negative charge in the latter. Theoretical investigation at the density functional theory (DFT) level shows difference in the molecular electronic distribution of 2 and 4, in agreement with the structural parameters and the IR stretching frequencies of the respective carbonyl moieties.

Comparative structural studies of 4-diazopyrazole derivatives by X-ray diffraction and theoretical investigation / G. Daidone, B. Maggio, M.V. Raimondi, G. Bombieri, N. Marchini, R. Artali. - In: HETEROCYCLES. - ISSN 0385-5414. - 65:11(2005), pp. 2753-2761.

Comparative structural studies of 4-diazopyrazole derivatives by X-ray diffraction and theoretical investigation

G. Bombieri;
2005

Abstract

The X-Ray crystal and molecular structures of the 4-pyrazol derivatives 3-methyl-4-diazo-5-benzamido-IH-pyrazole (4) and 3-benzamido-5-methyl-IHpyrazole (3) have been determined. A dimeric structure has been found for the first and polymeric for the second. A comparison of 4 with 1,3-dimethyl-4-diazo5-benzamido-1H-pyrazole (2) shows differences in the geometrical parameters of the pyrazole ring due to electron delocalization in 2 consequent to the nitrogen negative charge in the latter. Theoretical investigation at the density functional theory (DFT) level shows difference in the molecular electronic distribution of 2 and 4, in agreement with the structural parameters and the IR stretching frequencies of the respective carbonyl moieties.
Settore CHIM/08 - Chimica Farmaceutica
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/9542
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