Synthesis of a Novel Unexpected Cu(II)–Thiazolidine Complex—X-ray Structure, Hirshfeld Surface Analysis, and Biological Studies

Abstract

An unexpected trinuclear Cu(II)–thiazolidine complex has been synthesized by mixing CuCl2·2H2O with the Schiff base ligand, 1-(((4,5-dihydrothiazol-2-yl)ethylidene)hydrazono)methyl)phenol L, in ethanol. Unexpectedly, the reaction proceeded via the hydrolysis of the Schiff base L, followed by cyclization to afford 3-methyl-5,6-dihydrothiazolo[3,2-c][1,2,3]triazole (La), then complexation with the Cu(II) salt, forming the trinuclear [Cu3(La)4(Cl)6] complex. The complex was characterized by means of FTIR spectra, elemental analysis, and X-ray crystallography. In the trinuclear [Cu3(La)4(Cl)6] complex, there are two crystallographically independent hexa- and penta-coordinated Cu(II) sites, where the thiazolidine ligand La units act as a monodentate ligand and a linker between the Cu(II) centers. The crystal packing of the [Cu3(La)4(Cl)6] complex is primarily affected by the weak non-covalent C-H∙∙∙Cl interactions. In accordance with Hirshfeld surface analysis, the Cl∙∙∙H, H∙∙∙H, S∙∙∙H, and N∙∙∙H percentages are 31.9%, 27.2%, 13.5%, and 9.9%, respectively. X-ray photoelectron spectroscopy confirmed the oxidation state of copper as Cu(II), as well as the presence of two different coordination environments around copper centers. The complex showed interesting antibacterial activity against the Gram-positive bacteria S. subtilis, with MIC = 9.7 µg/mL compared to MIC = 4.8 µg/mL for the control, gentamycin. Moreover, the Cu(II) complex showed an equal MIC (312.5 µg/mL) against C. albicans compared to ketoconazole. It also exhibits a very promising inhibitory activity against colon carcinoma (IC50 = 3.75 ± 0.43 µg/mL).

A Cu-incorporated polymeric heterogeneous catalyst: exploring an expedient approach to construct amide bonds and extending its application to triazole hybrid amide synthesis

“…33,34 The observed binding energy difference of 19.7 eV along with the satellite peaks obtained at 942.6 eV provides evidence to designate that Cu is present in the form of Cu 2+ . 35 In Fig. 7c, the XPS C 1s spectra are shown for both polymer and Cupolymeric catalysts.…”

Novel Linear Trinuclear CuII Compound with Trapped Chiral Hemiaminal Ligand: Magnetostructural Study

“…Polynuclear molecular complexes containing copper(II) cations are characterized as having various structures and functions explored in fields such as chemistry, biochemistry, and materials science [1][2][3][4][5][6][7]. Also, different designs and arrangements of the Cu II cations have been studied for their potential use in catalytic reactions involving oxidation or reduction and in developing new magnetic materials [1,2,4,8].…”