Crystal Structure, Spectroscopic Characterization, DFT, Hirshfeld Surface and Energy Framework Analyses of (E)-4-bromo-5-methoxy-2-(((2-methoxyphenyl)imino)methyl)phenol monohydrate

Abstract

In this study, a bromine-substituted Schiff base derivative was effectively synthesized and its crystal structure was identified by single-crystal X-ray diffraction. The supramolecular properties of the compound were comprehensively investigated using experimental and theoretical approaches. A high degree of agreement was observed between the experimentally determined molecular geometry and the computationally optimized structure at the B3LYP/6-31G(d,p) level, confirming the reliability of the computational model. Fourier transform infrared spectroscopy revealed the presence of an azomethine bond and a strong intramolecular O-H···N hydrogen bonding, while UV–Visible spectroscopic analysis exhibited characteristic π→π*, n→π*, and intramolecular charge transfer transitions associated with the conjugated molecular framework. Hirshfeld surface analysis and fingerprint maps revealed that O-H···O and crystal water-mediated Ow-H···O hydrogen bonds have a significant role in crystal packing, whereas weaker interactions such as C-H···Br and C-H···O contacts contribute cooperatively to the stabilization of the supramolecular architecture. Energy framework analysis revealed that the dispersion energy is the major contributor to the total interaction energy, consistent with the presence of π···π stacking and van der Waals interactions. Furthermore, void analysis indicated a low void content within the unit cell, suggesting efficient molecular packing. Overall, the crystal stability of the investigated compound arises from the combined effects of strong hydrogen bonding and dispersion-driven interactions.