Synthesis and Structure of Novel Copper(II) Complexes with N,O- or N,N-Donors as Radical Scavengers and a Functional Model of the Active Sites in Metalloenzymes

Abstract

To evaluate the antioxidant activity of potential synthetic enzyme mimetics, we prepared new five copper(II) complexes via a self-assembly method and named them [Cu(2-(HOCH2)py)3](ClO4)2 (1), [Cu(2-(HOCH2)py)2(H2O)2]SiF6 (2), [Cu2(2-(HOCH2CH2)py)2(2-(OCH2CH2)py)2](ClO4)2 (3), [Cu(pyBIm)3](BF4)2·1.5H2O (4) and [Cu(py2C(OH)2)2](ClO4)2 (5). The synthetic protocol involved N,O- or N,N-donors: 2-(hydroxymethyl)pyridine (2-(HOCH2)py), 2-(hydroxyethyl)pyridine (2-(HOCH2CH2)py), 2-(2-pyridyl)benzimidazole (pyBIm), di(2-pyridyl)ketone (py2CO). The obtained Cu(II) complexes were fully characterised by elemental analysis, FTIR, EPR, UV-Vis, single-crystal X-ray diffraction and Hirshfeld surface analysis. Crystallographic and spectroscopic analyses confirmed chromophores of both monomeric ({CuN3O3} (1), {CuN2O4} (2), {CuN6} (4), {CuN4O2} (5)) and dimeric complex ({CuN2O3} (3)). Most of the obtained species possessed a distorted octahedral environment, except dimer 3, which consisted of two copper centres with square pyramidal geometries. The water-soluble compounds (1, 3 and 5) were selected for biological testing. The results of the study revealed that complex 1 in solutions displayed better radical scavenging activity than complexes 3, 5 and free ligands. Therefore, complex 1 has been selected for further studies to test its activity as an enzyme mimetic. The chosen compound was tested on the erythrocyte lysate of two groups of patients after undergoing chemotherapy and chemoradiotherapy. The effect of the tested compound (1) on enzyme activity levels (TAS, SOD and CAT) suggests that the selected complex can be treated as a functional mimetic of the enzymes.

Piperazin incorporated Schiff Base derivatives: Assessment of in vitro biological activities, metabolic enzyme inhibition properties, and molecular docking calculations

“…Antioxidants eliminate harmful free radical reactions and thus prevent degenerative diseases. [26,27] The TAS values of cells treated with the compounds are found generally high, but they are not statistically significant compared with the control group (p>0.05). Although the antioxidant capacity of the cell cultures treated with the target compounds increased, the differences were found to be insignificant (p > 0.05) in Table 4.…”

“…TAS, TOS, and oxidative stress index (OSI) were determined in triplicate experiments using commercially available Rel Assay Diagnostic kits. [ 27 ] Trolox was used as a standard for TAS analyses and hydrogen peroxide for TOS analyses. The OSI was calculated using the following equation: $$$\text{OSI}\,(\text{Arbitrary Unit})=\phantom{\rule{}{0ex}}\frac{\text{TOS},\,{\mathrm{\mu mol\; H}}_{2}{{\rm{O}}}_{2}\,\text{equiv}/{\rm{L}}}{\text{TAS},\,\text{mmol Trolox equiv}/\text{L X}\,10}.$$$…”

“…TAS, TOS, and oxidative stress index (OSI) were determined in triplicate experiments using commercially available Rel Assay Diagnostic kits. [27] Trolox was used as a standard for TAS analyses and hydrogen peroxide for TOS analyses. The OSI was calculated using the following equation:…”

Hirshfeld Surface Analysis for Investigation of Intermolecular Interaction of Molecular Crystals

“…Although it is possible to make a judgment by the usual method based on the observation of the crystal structure, there are also analytical reports on the types of hydrogen bonds involving halogen atoms with strong polarity and sulfur atoms with large polarization. Noor observed intermolecular C-H•••Br hydrogen bonding in halide-containing mono(aminopyridine) Fe(II) complexes [10] [12]. Ghazzy [21].…”

Ultrasonic Clusterization Process to Prepare [(NNCO)6Co4Cl2] as a Novel Double-Open-Co4O6 Cubane Cluster: SXRD Interactions, DFT, Physicochemical, Thermal Behaviors, and Biomimicking of Catecholase Activity

“…Lately, exceptional care for the coordination chemistry domain has been focused on nitrogen heteroaromatic alcohol molecules like a family of commercially accessible compounds acquiring adaptability in complexation potentiality. − A large category of fascinating engineering of complexes is built from N,O – donor alcohol building units. − Due to their optimal and fine characteristics, these molecules are extensively utilized like a crux for the construction of important materials based on polynuclear clusters. − The design and synthesis of polynuclear metal cluster-based coordination cages have attracted much interest, due to their esthetic structure and fascinating quantum mechanical properties, in applications including information storage, quantum computing, gas storage, drug delivery, conversion of CO 2 , and crucial contribution in the catalysis of the splitting of water via enzymatic photosystem II {PS-II} of photosynthetic organisms. − This economic and ecofriendly model is the foundation for all envisioned solar fuel-based green energy strategies; accordingly, the biomodel is considered to be the efficient, simple, and clear starting phase for any bioinspired strategy. − As a result, the draft and assembly of the polynuclear metal cluster-based coordination cages are already charming and yet remain a synthetic challenge. − While most advances concerned the challenging preparation and characterization of the Mn-cluster oxygen evaluation conversion {OEC} mimic, − {Co 4 O 6 } cubane water oxidation catalysts {WOCs} appear to be preferred and ideal typical plan model systems for the essential oxidation reaction − and the creation of excellent photoanodes. − …”