Co-crystallization of a neutral mol-ecule and its zwitterionic tautomer: structure and Hirshfeld surface analysis of 5-methyl-4-(5-methyl-1H-pyrazol-3-yl)-2-phenyl-2,3-di-hydro-1H-pyrazol-3-one 5-methyl-4-(5-methyl-1H-pyrazol-2-ium-3-yl)-3-oxo-2-phenyl-2,3-di-hydro-1H-pyrazol-1-ide monohydrate.

ABSTRACT: The title compound, 2C14H14N4O·H2O, comprises a neutral mol-ecule containing a central pyrazol-3-one ring flanked by an N-bound phenyl group and a C-bound 5-methyl-1H-pyrazol-3-yl group (at positions adjacent to the carbonyl substituent), its zwitterionic tautomer, whereby the N-bound proton of the central ring is now resident on the pendant ring, and a water mol-ecule of crystallization. Besides systematic variations in geometric parameters, the two independent organic mol-ecules have broadly similar conformations, as seen in the dihedral angle between the five-membered rings [9.72?(9)° for the neutral mol-ecule and 3.32?(9)° for the zwitterionic tautomer] and in the dihedral angles between the central and pendant five-membered rings [28.19?(8) and 20.96?(8)° (neutral mol-ecule); 11.33?(9) and 11.81?(9)°]. In the crystal, pyrazolyl-N-H?O(carbon-yl) and pyrazolium-N-H?N(pyrazol-yl) hydrogen bonds between the independent organic mol-ecules give rise to non-symmetric nine-membered {?HNNH?NC3O} and {?HNN?HNC3O} synthons, which differ in the positions of the N-bound H atoms. These aggregates are connected into a supra-molecular layer in the bc plane by water-O-H?N(pyrazolide), water-O-H?O(carbon-yl) and pyrazolyl-N-H?O(water) hydrogen bonding. The layers are linked into a three-dimensional architecture by methyl-C-H??(phen-yl) inter-actions. The different inter-actions, in particular the weaker contacts, formed by the organic mol-ecules are clearly evident in the calculated Hirshfeld surfaces, and the calculated electrostatic potentials differentiate the tautomers.

SUBMITTER: Asiri AM 

PROVIDER: S-EPMC6505615 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature