A new polymorph of 5-bromo ortho vanillin: Synthesis, characterization, crystal engineering, Hirshfeld surface, calculation of interaction energy, and energy frameworks

This article reports on one of the newly synthesized 5-bromo ortho vanillin (C8H7BrO3) (1) polymorphs, whose X-ray structure was determined by single crystal X-ray diffraction. The polymorph attains a monoclinic system, space group P21/c, V = 824.3(9), and Z = 4. In this work, the cell parameters observed are a = 4.080(2) Å, b = 20.733(12) Å, c = 9.844(7) Å, and β = 98.4(2). Polymorph 1 is compared with the reported compound 2. The article discusses the structural characterization of polymorph 1 using HRMS, FTIR, UV-vis, 1H/13C NMR, and 13C DEPT NMR spectroscopy, and explores NCSI (noncovalent supramolecular interactions) within the crystal network. Furthermore, the Hirshfeld surface and 2D fingerprint plot analyze the presence of significant H···Br (20.8%) and H···O (23.8%) contacts in the crystal assembly. In addition, interaction energies and energy frameworks have been calculated. The study revealed that the constructed frameworks fall into electrostatic (Eele, red cylinders) and dispersion (Edis, green cylinders) categories, along with total interaction energies (Etot, blue cylinders). The polymorph is rationalized using physicochemical, crystallographic, Hirshfeld surface, interaction energy and energy frameworks.