Experimental and theoretical studies on bis (6-nitroquinoline) fumaric acid co-crystal

Abstract

6-Nitroquinoline fumaric acid (C11H8N2O4), an organic co-crystal is grown using slow evaporation solution growth technique. The grown crystal is characterized by single crystal X-ray diffraction (SCXRD) and the title compound is crystallized in monoclinic crystal system with P21/n centrosymmetric space group. The OH···N and CH···O hydrogen bonds influence heterodimer formation in the crystal structure. The optical absorption spectrum of the title compound shows an absorption peak at 333 nm which contributes to π→π* transition. The transmission spectrum shows about 82% transparency in the visible region with lower cutoff wavelength 370 nm. The vibrational modes and assignments of functional groups are done using FTIR and Raman spectroscopic analyses. The CO stretching is the most characteristic vibration of the carboxylic acid group and it typically appears at 1393 cm−1. The thermal behavior of the present compound is evaluated by TG/DSC techniques and the melting point of the title crystal is 191 °C. The finger print plots show that H···O (41.9%) interactions are dominated interactions. These interactions are responsible for CH···O hydrogen bonds which play vital role in the structure stabilization. The first order hyperpolarizability value is calculated using B3LYP method with the extended 6–311++G(d,p) basis set and it is found as 4.5 times larger than that of urea.