Hydrogen-bonded structures of the isomeric 2-, 3- and 4-carbamoylpyridinium hydrogen chloranilates

Three isomeric salts of chloranilic acids with picolinamide, nicotinamide and isonicotinamide namely hydrogen bonded, 2-,3- and 4-carbamoylpyridinium hydrogen chloranilates have been demonstrated. The shortest interactions between the cation and anion in the isomeric salt are pyridinium bifurcated hydrogen bonds, which acts as the primary intermolecular interaction in each crystal structure. The packing motif is similar to that of 3-carboxypyridinium hydrogen chloranilate, which crystallizes in the same space group Pc is effectively isostructural. H atoms attached to O and N atoms were found in a difference Fourier map and refined isotropically. The neighboring layers related to each other by a c-glide plane are linked by second amide hydrogen bond to form a three dimensional hydrogen bond network.