Solid state synthesis, structural, physicochemical and optical properties of an inter-molecular compound: 2-hydroxy-1, 2-diphenylethanone-4-nitro-o-phenylenediamine system

Abstract

The phase diagram of 2-hydroxy-1, 2-diphenylethanone (HDPE)-4-nitro-o-phenylenediamine (NOPDA) system, determined by the thaw-melt method, gives two eutectics E1 (m p = 66.0°C) and E2 (m p = 155.0°C) with 0.30 and 0.55mol fractions of NOPDA, respectively, and an 1:1 inter-molecular compound (IMC) (m p 162.0°C). This IMC was synthesized by adopting the green synthetic method of solid state reaction. While its formation and structure were confirmed by the X-ray diffraction and spectroscopic methods, the ORTEP view gives mode of crystal packing, C‒H…O, C‒H…N, π-π stacking and the inter-molecular hydrogen bonding in the compound. The single crystal of the IMC shows 53% transmission and emits significantly higher dual fluorescence, and the band gap was computed to be 3.04eV. The values of solubility of the IMC, measured in the temperature range 304–322K, satisfy the mole fraction (X) and temperature equation: Xeq= 5.1324 × 10−7 e 0.01356T.