Design, structural, C–H….H–C supramolecular interactions and computational investigations of Cd(N∩N″)X2 complexes based on an asymmetrical 1,2-diamine ligand: physicochemical and thermal analysis

Abstract

Complexes [N∩N″CdX2] (X = Cl (1), I (2) and N∩N″ is N1,N1,N2-triethylethane-1,2-diamine) are reported. The desired complexes were prepared under identical synthetic conditions and characterized by ESI-MS, UV-vis, CHN-elemental analyses, 1H-NMR and FT-IR. The structure of 2 has been confirmed by XRD studies, wherein N∩N″CdI2 complex crystallized in the monoclinic space group P21/n with a = 9.245(8) Å, b = 15.190(12) Å, c = 10.905(9) Å, V = 1491(2) Å3, and Z = 4. Distorted tetrahedral geometry around the Cd(II), constructed from 2N and 2I, was confirmed by single crystal XRD. Only C–H….H–C supramolecular interactions have been detected in 2. Hirshfeld surface analysis (HSA) reflected presence of weak H….H noncovalent supramolecular interactions and presence of no H….I bonds are consistent with the experimental XRD-result. Mulliken population charge and molecular electrostatic potential (MEP) calculations for N∩N″CdI2 were carried out to support the XRD-result. The computed electronic parameters B3LYP-IR, frontier molecular orbital (FMO), time-dependent self-consistent field/density functional theory (TD-SCF/DFT), and the global reactivity descriptors (GRD) quantum numbers were estimated and compared to the experimental data. Thermal stability studies of the N∩N″CdI2 complex were carried out via TGA/DTG from 0 to 800 °C in open atmosphere.