New 1D Cd(II) coordination polymer based on L‒arginine ligand; Synthesis, X−ray structure, Hirshfeld analysis, DFT studies, and biological activity

Abstract

The structural aspects of the newly synthesized 1D coordination polymer, [Cd(μ–L–Arg)(OSO3)(H2O)2]n with L−arginine (L−Arg) are presented. The Cd(II) is hepta−coordinated with one L‒Arg as a bridged bidentate ligand in addition to two water molecules and one sulphate group where both are monodentate ligands. The expansion of the coordination polymer along a–direction is occurred via two extra Cd–O bonds with the carboxylate group from another L−Arg in a neighboring complex unit. The significant interactions that controlled the molecular packing are O···H (52.8%) and H···H (32.2%) based on Hirshfeld topology analysis. The 1D polymeric structure of the Cd(II) is confirmed by the presence of obvious red spots in dnorm map related to the Cd−O coordinate bonds with the neighbouring molecule. The AIM investigation revealed that the Cd–O and Cd–N bonds have low covalent characters. The charge of Cd(II) is changed to 1.374 e as a consequence of complexation with the ligand groups. The orbital-orbital interactions included in the Cd–N and Cd–O bonds are analyzed using NBO calculations. The anticancer activity of the studied complex and L−Arg were screened versus human colorectal cell line (HCT−116). The results show that, the Cd(II) complex has better activity towards the tested cell line (IC50 = 166.15 ± 6.95 µg/mL) than its free ligand (IC50 = 224.42 ± 8.34 µg/mL). Also, the complex exhibits somewhat higher antibacterial activity compared with L‒Arg.