Linear dicarboxylato and tridentate chelating ligands coordinated Cu(II) complexes: Syntheses, crystal structures, protein binding and cytotoxicity studies

• Published in: Polyhedron 2022-08, Vol.222, p.115888, Article 115888
• Main Authors: Patra, Apu, Sahay, Osheen, Mahish, Manas Kumar, Das, Mahua Rani, Saren, Dama, Paul, Aparup, Vojtíšek, Pavel, Santra, Manas Kumar, Manna, Subal Chandra
• Format: Article
• Language: English
• Subjects: Crystal structure; Cytotoxicity studies; Dinuclear Cu(II) complex; Linear dicarboxylato bridged; Protein binding
• ISSN: 0277-5387
• DOI: 10.1016/j.poly.2022.115888

Three dinuclear supramolecular copper(II) complexes have been synthesized and characterized by single crystal X-ray diffraction, spectroscopic studies and thermal analysis. The interaction of the complexes with bovine serum albumin (BSA) was investigated using the fluorescence spectroscopic technique and the values of the binding constants (Kbin) are (15.9± 0.13) × 104M−1 (for 1), (10.3± 0.08) × 104M−1 (for 2) and (11.2± 0.37) × 104M−1 (for 3). The cytotoxicity of the complexes was tested using breast cancer MCF7 and MDA-MB-231 cells, and normal breast epithelial MCF10A cells. The MTT results reveal that the complexes potently suppressed the growth of the breast cancer cell lines MCF7 and MDA-MB-231, and the MCF10A cells. Complexes 1–3 inhibited fifty percent growth (IC50) at 5.80 ± 1.47, 20.85 ± 1.25 and 5.10 ± 1.23 μM for MCF7 cells, respectively. [Display omitted] Three dinuclear copper(II) complexes, [Cu2(L1)2(tp)]∙4H2O (1), [Cu2(L1)2(ppda)(H2O)2]∙2H2O (2) and [Cu2(L2)2(tp)(CH3OH)2]∙2H2O (3) (where HL1 = 2-methoxy-6-[(2-morpholin-4-yl-ethylimino)-methyl]-phenol, HL2 = 2-ethoxy-6-[(2-morpholin-4-yl-ethylimino)-methyl]-phenol, tp = terephthalate, ppda = p-phenylenediacrylate), have been synthesized and characterized by single crystal X-ray diffraction, FTIR, mass spectrometry and thermal analysis. All the complexes crystallize in the monoclinic system with the space group P21/n (for 1 and 2) and P21/c (for 3) as centrosymmetric species. In 1 and 3, two CuL1 and CuL2 units, respectively are bridged by a terephthalate (tp) anion, whereas in 2 the bridging unit is p-phenylenediacrylate (ppda). The copper atoms in 1 exhibit a square planar coordination geometry, while in 2 and 3 the metals have a square pyramidal environment. All of 1–3 form 1D supramolecular chains through C-H…π interaction. The interaction of the complexes with bovine serum albumin (BSA) was investigated using a fluorescence spectroscopic technique. The values of the binding constant are (15.9 ± 0.13) × 104 M−1 (for 1), (10.3 ± 0.08) × 104 M−1 (for 2) and (11.2 ± 0.37) × 104 M−1 (for 3). Using the Scatchard equation, the calculated values of the number of binding sites (n) are all around 1, signifying the presence of a single binding site in serum albumins for the Cu(II) complexes. The cytotoxicity of the complexes was tested using breast cancer MCF7 and MDA-MB-231 cells, along with normal breast epithelial MCF10A cells. MTT results reveal that the complexes potently suppressed the growth