Structure of imidazolium-N-phthalolylglycinate salt hydrate: Combined experimental and quantum chemical calculations studies

An organic supramolecular salt hydrate (imidazolium:N-phthalolylglycinate:H2O; IM⁺-NPG⁻-HYD) has been examined for its charge-transfer (CT) characteristics. Accordingly, IM⁺– NPG⁻–HYD has been characterized thoroughly using various spectroscopic techniques. Combined experimental and quantum chemical studies, along with wave function analysis, were performed to study the non-covalent interactions and their role in CT in the supramolecular salt hydrate. Notably, IM⁺–NPG⁻–HYD crystalizes in two configurations (A and B), both of which are held together via non-covalent interactions to result in a three-dimensional CT supramolecular assembly. The through-space CT occurs from NPG^– (donor) to IM⁺ (acceptor), and this was mediated via non-covalent forces. We demonstrated the role of π–π stacking interactions (mixed-stacking donor-acceptor interactions) in the presence of charge-assisted hydrogen bonds in the regulation of CT properties in the self-assembly of the IM⁺–NPG⁻–HYD salt hydrate.