Hydrogen-bonded supramolecular architecture in nonlinear optical ammonium 2,4-dinitrophenolate hydrate

Single crystals of ammonium 2,4-dinitrophenolate hydrate (ADH) were grown by the slow evaporation solution growth technique. The structure is elucidated by single-crystal X-ray diffraction analysis and the crystal belongs to an orthorhombic system with noncentrosymmetric space group Pna2₁. The second harmonic generation efficiency of ADH is superior to that of the reference material KH₂PO₄. The X-ray study reveals that molecules are associated by weak C—H...O, O—H...N, N—H...π and π–π stacking interactions, which are responsible for the formation and strengthening of the supramolecular assembly. Inter- and intramolecular hydrogen-bonding interactions support the supramolecular architecture in the crystal packing. Three different types of architecture, i.e. column-like packing, a sandwich model of packing and a cluster network type of infrastructure, are observed. Optical studies reveal that the absorption is minimum in the visible region and the cutoff wavelength is at ∼240 nm. The band-gap energy was estimated by the application of the Kubelka–Munk algorithm. The powder X-ray diffraction pattern reveals the good crystallinity of the as-grown specimen. Investigation of the intermolecular interactions and crystal packing using Hirshfeld surface analysis, based on single-crystal X-ray diffraction, reveals that the close contacts are associated with molecular interactions. Fingerprint plots of Hirshfeld surfaces were used to locate and analyze the percentage of hydrogen-bonding interactions.