P. Channar, A. Saeed, M. Erben
Sep 5, 2019
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Journal
Journal of Molecular Structure
Abstract
Abstract The title compound (3) was obtained by cyclocondensation of 4-methylbenzohydrazide (2) with 3-chloropentane-2,4-dione (1) in dry ethanol in presence of acetic acid and recrystallization from ethanol. The molecular and crystal structure of the new pyrazole derivative was determined by single crystal X-ray diffraction. It crystallizes in triclinic system with space group P-1. The molecules in the crystal adopt an anti conformation for the mutual orientation of the C O double bond with respect to the N N single bond. The pyrazole and phenyl rings are very far from being coplanar, with a dihedral angle of 49.62(4)°. Additionally, full geometry optimizations and frequency calculations were computed at the B3LYP/6-311++G(d,p) level of approximation. The NBO population analysis showed that the lpp(N1) lone pair orbital contributes to a strong resonance interactions with both adjacent π*(N2=C2) and π*(C5=C4) antibonding orbitals of the pyrazole group.