1. Comparative Structural Studies of 4-Diazopyrazole Derivatives by X-Ray Diffraction and Theoretical Investigation
- Author
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Giuseppe Daidone, Nicoletta Marchini, Maria Valeria Raimondi, Benedetta Maggio, Gabriella Bombieri, Roberto Artali, DAIDONE G, MAGGIO B, RAIMONDI MV, BOMBIERI G, MARCHINI N, and ARTALI R
- Subjects
Pharmacology ,Chemistry ,Organic Chemistry ,Electron delocalization ,Pyrazole ,Ring (chemistry) ,Analytical Chemistry ,Crystal ,Crystallography ,chemistry.chemical_compound ,Negative charge ,X-ray crystallography ,X-Ray, crystal, molecular, structures, derivatives ,Density functional theory - Abstract
The X-Ray crystal and molecular structures of the 4-pyrazol derivatives 3-methyl-4-diazo-5-benzamido-1H-pyrazole (4) and 3-benzamido-5-methyl-1H-pyrazole (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-diazo-5-benzamido-lH-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.
- Published
- 2005