Macrocyclic “tet a”-Derived Cobalt(III) Complex with a N,N′-Disubstituted Hexadentate Ligand: Crystal Structure, Photonuclease Activity, and as a Photosensitizer

Abstract

A cobalt(III) complex, [Co(L)]Cl (complex 1 , where L = 1,8-[ N , N -bis{(3-formyl-2-hydroxy-5-methyl)benzyl}]-1,4,8,11-tetraaza-5,5,7,12,12,14-hexamethylcyclotetradecane) with distorted octahedral geometry has been synthesized and characterized using various spectroscopic techniques. The structure of the ligand has remarkably rich hydrogen intermolecular interactions such as H···H, H···C/C···H, and H···O/O···H that vary with the presence of the metal ion, and the structure of complex 1 has Cl···H interactions; this result has been proved by Hirshfeld surface and two-dimensional (2D) fingerprint maps analyses. The complex exhibits a quasi-reversible Co(III)/Co(II) redox couple with E 1/2 = −0.76 V. Calf thymus DNA (CT DNA) binding abilities of the ligand and complex 1 were confirmed by spectroscopic and electrochemical analyses. According to absorption studies, the ligand and complex 1 bind to CT DNA via intercalative binding mode, with intrinsic binding strengths of 1.41 × 10 3 and 8.64 × 10 3 M –1 , respectively. A gel electrophoresis assay shows that complex 1 promotes the pUC19 DNA cleavage under dark and light irradiation conditions. Complex 1 has superior antimicrobial activity than the ligand. The cytotoxicity of complex 1 was tested against MDA-MB-231 breast cancer cells with values of IC 50 of 1.369 μg mL –1 in the dark and 0.9034 μg mL –1 after light irradiation. Besides, cell morphological studies confirmed the morphological changes with AO/EB dual staining, reactive oxygen species (ROS) staining, mitochondria staining, and Hoechst staining on MDA-MB-231 cancer cells by fluorescence microscopy. Complex 1 was found to be a potent antiproliferative agent against MDA-MB-231 cells, and it can induce mitochondrial-mediated and caspase-dependent apoptosis with activation of downregulated caspases. The biotoxicity assay of complex 1 on the development of Artemia nauplii was evaluated at an IC 50 value of 200 μg mL –1 and with excellent biocompatibility.

An Integrated Analysis of Mechanistic Insights into Biomolecular Interactions and Molecular Dynamics of Bio-Inspired Cu(II) and Zn(II) Complexes towards DNA/BSA/SARS-CoV-2 3CLpro by Molecular Docking-Based Virtual Screening and FRET Detection

“…Equation (S24) is acquired from the Stern–Volmer Equation (S14) (Figure S29 and Table 6 ) ( ESI-2a ) . The values of S and K b are estimated from Equation (S30) using S = (intercept/4) 1/2 and (K b = 2S (Slope/intercept), respectively, from the linear regression plot of (C p /C f ) versus [DNA] by method II [ 97 , 98 , 99 ] ( Figure S30 and Table 6 ). In addition, base pair sites with a molecule of the compound are referred to as “binding site size” (S), and the evaluated S values were found in the range from 0.2480 to 0.4460 bp ( Table 6 ).…”

Exploring the antioxidant, antimicrobial, cytotoxic and biothermodynamic properties of novel morpholine derivative bioactive Mn(ii), Co(ii) and Ni(ii) complexes – combined experimental and theoretical measurements towards DNA/BSA/SARS-CoV-2 3CLPro

“…Equation ( 26) was obtained from the revision of equation (25). Also, binding site size (S, bp) and K b are estimated from equation (30) from the linear regression plot of (C p /C f ) versus [DNA] by method-II [90][91][92] (Fig. S33 & Table 6).…”

Ferrocenyl chalcone armed macrocyclic tet a‐based cobalt(II) and copper(II) complexes: DNA photocleavage activity and photocytotoxicity

“…The complex 1 was synthesised by reaction of ethanolic solution (20 ml) of precursor cobalt complex (CoL) [14] (0.26 g, 0.4 mM) and KOH (0.4 g, 0.8 mM) added dropwise to the hot solution of acetylferrocene (0.18 g, 0.8 mM) in chloroform (CHCl 3 ) (30 ml) with continuous stirring at 80 C. After completion of the reaction, the mixture was neutralised with 1 M HCl to get the dark red precipitate. The precipitate was separated by filtration and washed with cold water.…”