Search for molecular crystals with NLO properties: 3-Nitrophenol with nicotinamide and isonicotinamide

Two molecular complexes of amides (nicotinamide and isonicotinamide) with 3-nitrophenol are characterized by X-ray diffraction and spectroscopic studies. Crystal structure analyses at 100 K revealed different features to distinguish the co-crystals. The asymmetric unit of the crystal structure of nicotinamide-3-nitrophenol (1:1), 1, consists of two symmetry-independent nicotinamide molecules and two symmetry-independent 3-nitrophenol molecules. The crystal structure of 1 displays an extended hydrogen bond network generated by OH⋯O, NH⋯O and NH⋯N interactions. The structure of isonicotinamide-3-nitrophenol (1:1), 2, contains OH⋯N hydrogen bonds engaging the pyridine N atom. In 2, the amide forms a R22(8) homodimer which is absent in 1. The complex 1 shows relatively efficient second harmonic frequency generation.