A Combined Theoretical Calculation and Hirshfeld Surface Analysis of Cooperative Non‐covalent Interactions in the Crystal Packing in [Cu(L1)2(EDA)

Abstract

The monomeric complex [Cu(L1)2(EDA)] (I) [L1 = 2,4‐dinitrobenzoic acid, EDA = ethylenediamine), was solved in orthorhombic space group (Pbca) and characterized by elemental analysis, IR spectroscopy, powder XRD analysis, and single‐crystal X‐ray crystallography, in addition to photoluminescence and thermal stability investigation. The Cu2+ ion is connecting with two L1 through monodentate mode of coordination and two nitrogen atoms from EDA. I is associated through cooperative non‐covalent interactions, which are also responsible for the strengthening of the molecular assembly and organize it into a supramolecular 2D motif. Hirshfeld surface analysis was also applied to investigate the cooperative non‐covalent supramolecular interactions and the results were compared with the single‐crystal X‐ray diffraction data. To get clear insights into the both species, electronic properties such as HOMO‐LUMO, electronic chemical potential and other derived parameters were also highlighted using DFT calculations at M06‐2X/ 6‐31G** level of theory. The observed photoluminescence of complex I arises mainly from an excited LLCT state with small MLCT contributions (from Cu2+ to the unoccupied p orbital of L1). The presented work exhibits another example of the utility and prosperity of such kinds of subtle information and features especially, and for complex I at molecular level, generally.