Two mefenamic acid derivatives: structural study using powder X-ray diffraction, Hirshfeld surface and molecular electrostatic potential calculations

Abstract

Abstract Two mefenamic acid (1) derivatives, prop-2-ynyl 2-(2,3-dimethylphynylamino)benzoate (2) and N′-(dihydro-2H-pyran-4(3H)-ylidene)-2-((2,3-dimethylphenyl)amino)benzohydrazide (3), have been synthesized and their crystal structures have been determined from laboratory powder X-ray diffraction data. The DFT optimized molecular geometry in 2 and 3 agrees closely to that obtained from the crystallographic study. The nature of intermolecular interactions in 2 and 3 has been analyzed through Hirshfeld surfaces and two-dimensional fingerprint plots, and compared with that in the mefenamic acid polymorphs. Intermolecular N–H···N, C–H···O/N and C–H···π(arene) interactions in 2 and 3 assemble molecules into two and three-dimensional supramolecular frameworks, respectively. Hydrogen-bond based interactions in 2 and 3 have been complimented by calculating molecular electrostatic potential surfaces. Hirshfeld surface analyses of 2, 3, three mefenamic acid polymorphs and a few related mefenamic acid derivatives retrieved from the Cambridge Structural Database (CSD) indicate that about 80% of the Hirshfeld surface areas in these compounds are due to H···H and C···H/H···C contacts.