A new pseudopolymorph of diphenic acid and 4,4′-bipyridine co-crystal: Structural and theoretical study

A new pseudopolymorph (B; tetragonal, I41/acd) of the cocrystal biphenyl-2,2′-dicarboxylic acid (diphenic acid) and 4,4′-bipyridine was synthesized. Its solid-state structure and supramolecular synthons responsible for extending the supramolecular network have been compared with those of the previously reported polymorph (A; triclinic, P 1 ¯ ). DFT calculations at the B3LYP/6-311G++ (2d,2p) level have been performed. Energies of the intermolecular hydrogen bonds in the crystal structure were calculated and their electronic aspects were investigated by NBO and AIM analysis.