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The copper(II) complexes [Cu(L)NO 3 ] (1-9) of newer N 3 O ligands (L1-L9) have been synthesized and characterized. The molecular structure of 1, 4, and 7 exhibited nearly a perfect square pyramidal geometry (τ, 0.04-0.11). The Cu-O Phenolate bonds (~ 1.91 Å) are shorter than the Cu-N bonds (~ 2.06 Å) due to the stronger coordination of anionic phenolate oxygen. The Cu(II)/Cu(I) redox potentials of 1-9 appeared around -0.102 to -0.428 V versus Ag/Ag + in water. The electronic spectra of the complexes showed the d-d transitions around 643-735 nm and axial EPR parameter (g || , 2.243-2.270; A ||, 164-179 × 10 -4  cm -1 ) that corresponds to square pyramidal geometry. The bonding parameters α 2 , 0.760-0.825; β 2 , 0.761-0.994; γ 2 , 0.504-0.856 and K || , 0.698-0.954 and K ⊥ , 0.383-0.820 calculated from EPR spectra and energies of d-d transitions. The complexes catalyzed the conversion of substrate 2-aminophenol into 2-aminophenoxazine-3-one using molecular oxygen in the water and exhibited the yields of 41-61%. The formation of the product is accomplished by the appearance of a new absorption band at 430 nm and the rates of formation were calculated as 6.98-15.65 × 10 -3  s -1 in water. The reaction follows Michaelis-Menten enzymatic reaction kinetics with turnover numbers (k cat ) 9.11 × 10 5  h -1 for 1 and 4.66 × 10 5  h -1 for 9 in water. The spectral, redox and kinetic studies were performed in water to mimic the enzymatic oxidation reaction conditions., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Overexpression of cysteine cathepsins proteases has been documented in a wide variety of cancers, and enhances the l-cysteine concentration in tumor cells. We report the synthesis and characterization of copper(ii) complexes [Cu(L1) 2 (H 2 O)](SO 3 CF 3 ) 2 , 1, L1 = 3-phenyl-1-(pyridin-2-yl)imidazo[1,5-a]pyridine, [Cu(L2) 2 (SO 3 CF 3 )]SO 3 CF 3 , 2, L2 = 3-(4-methoxyphenyl)-1-pyridin-2-yl-imidazo[1,5-a]pyridine, [Cu(L3) 2 (H 2 O)](SO 3 CF 3 ) 2 , 3, L3 = 3-(3,4-dimethoxy-phenyl)-1-pyridin-2-yl-imidazo[1,5-a]pyridine and [Cu(L4) 2 (H 2 O)](SO 3 CF 3 ) 2 , 4, L4 = dimethyl-[4-(1-pyridin-2-yl-imidazo[1,5-a]pyridin-3-yl)phenyl]amine as 'turn-on' optical imaging probes for l-cysteine in cancer cells. The molecular structure of complexes adopted distorted trigonal pyramidal geometry (τ, 0.68-0.87). Cu-N py bonds (1.964-1.989 Å) were shorter than Cu-N imi bonds (2.024-2.074 Å) for all complexes. Geometrical distortion was strongly revealed in EPR spectra, showing g ‖ (2.26-2.28) and A ‖ values (139-163 × 10 -4 cm -1 ) at 70 K. The d-d transitions appeared around 680-741 and 882-932 nm in HEPES, which supported the existence of five-coordinate geometry in solution. The Cu(ii)/Cu(i) redox potential of 1 (0.221 V vs. NHE) was almost identical to that of 2 and 3 but lower than that of 4 (0.525 V vs. NHE) in HEPES buffer. The complexes were almost non-emissive in nature, but became emissive by the interaction of l-cysteine in 100% HEPES at pH 7.34 via reduction of Cu(ii) to Cu(i). Among the probes, probe 2 showed selective and efficient turn-on fluorescence behavior towards l-cysteine over natural amino acids with a limit of detection of 9.9 × 10 -8 M and binding constant of 2.3 × 10 5 M -1 . The selectivity of 2 may have originated from a nearly perfect trigonal plane adopted around a copper(ii) center (∼120.70°), which required minimum structural change during the reduction of Cu(ii) to Cu(i) while imaging Cys. The other complexes, with their distorted trigonal planes, required more reorganizational energy, which resulted in poor selectivity. Probe 2 was employed for optical imaging of l-cysteine in HeLa cells and macrophages. It exhibited brighter fluorescent images by visualizing Cys at pH 7.34 and 37 °C. It showed relatively less toxicity for these cell lines as ascertained by the MTT assay.

We synthesised a sequence of structurally related copper(II) complexes of Schiff base ligands, 2-[(2-benzylamino-ethylimino)-methyl]-phenol [L1(H)], 2-[(2-benzylamino-ethylimino)-methyl]-4-methyl-phenol [L2(H)], and 2-[(2-benzylamino-ethylimino)-methyl]-4-bromo-phenol [L3(H)]. The complexes were characterized by ATR, UV-vis, EPR, ESI-MS, single crystal XRD, and elemental analyses. Based on the crystal structure, the ligand was coordinated to the copper(II) centre in a tridentate mode through phenolate(oxygen), imine nitrogen and amine nitrogen in an NNO fashion and the azide moiety served as an auxiliary ligand. Furthermore, we have investigated the antimicrobial activities of copper(II) complexes against clinically relevant fungal strains, including Candida albicans, Candida glabrata, and Candida tropicalis, as well as bacteria such as Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA), representing Gram-negative and Gram-positive pathogenic strains. Comparing the activity of complex 2 (128–512 μg mL−1) to complex 3 (64–128 μg mL−1), the latter demonstrated more potent effectiveness against all of the tested fungal strains. The activity of the complexes against MRSA reveals the inhibitory concentrations of 1024 μg mL−1 for 1, 128 μg mL−1 for 2, and 256 μg mL−1 for 3. It is worth mentioning that, at their minimum inhibitory concentrations (MICs), the complexes are not toxic to Galleria mellonella. Furthermore, the spot and broth microdilution assay results were in good agreement with the actual metabolic viability of bacterial and fungal strains, in which the complexes were active while having no effect on the metabolite resazurin. Additionally, in silico studies have been employed to elucidate both non-bonding interactions and the mode of action across protein sequences of experimentally studied microbes. The performance of complexes closely mirrored the reactivity order determined in in vitro studies. The impeding properties of complexes can be due to the dysfunctioning of virulent genes and signalling proteins and also affect the activities of transferase and transcriptase proteins. Overall, the complexes are promising candidates for antimicrobial drug development. We anticipate utilising these molecules for clinical purposes. [ABSTRACT FROM AUTHOR]

Eight novel mixed-ligand copper(II) complexes of the type [Cu(L)(phen)](ClO4) (1–8) synthesized from S-methyldithiocarbazate Schiff bases [H(L1)–H(L8)] and 1,10-phenanthroline (phen) ligands have been characterized using various physicochemical, spectroscopic and electrochemical methods. The structures of seven out of the eight Cu(II) complexes have been determined by single crystal X-ray diffraction. The coordination geometry around the Cu(II) ion is distorted square pyramidal (τ, 0.24–0.49). The heterocyclic and azomethine nitrogens along with thiolato sulphur of the deprotonated tridentate ligand (NNS) and one of the imine nitrogens of phen form the equatorial CuN3S square plane, while the other imine nitrogen atom of phen occupies the axial position. The geometry of the Cu(II) center in the solid state is preserved in DMF solution, stabilizing to distorted square pyramidal, as suggested by the low-temperature EPR data g‖ > g⊥ > 2.0. Cyclic voltammetry showed that the Cu(II) complexes display quasi-reversible electrochemistry. The efficiency of the complexes in killing the human lung epithelial adenocarcinoma cells (A549) has also been studied along with the cell viability assay against the noncancerous human lung epithelial cells (L132) under in vitro conditions. They were found to exhibit excellent cytotoxicity against A549 cancer cells without affecting the normal L132 cells. The activity of all the complexes was significantly superior to that of cisplatin. The 2′,7′-dichlorodihydrofluorescein diacetate (DCHF-DA) experiment indicated that cancer cells produce more reactive oxygen species (ROS) than normal cells. Further, they cause cell death mainly through apoptotic mode, as revealed by the observation of a higher percentage of apoptotic cells in acridine orange (AO) or ethidium bromide (EB) or 4′,6′-diamidino-2-phenylindole (DAPI) stained cancer cells. Thus, ROS generation in tumor cells is implicated in cytotoxicity, demonstrating the versatile nature of presently accessible mixed-ligand copper(II) complexes for cancer therapy by means of ROS-induced apoptotic cell death. [ABSTRACT FROM AUTHOR]

Recently, mixed-ligand copper(II) complexes have received much attention in searching for alternative metallodrugs to cisplatin. A series of mixed ligand Cu(II) complexes of the type [Cu(L)(diimine)](ClO4) 1–6, where the HL is 2-formylpyridine-N4-phenylthiosemicarbazone and the diimine is 2,2′-bipyridine (1), 4,4′-dimethyl-2,2′-bipyridine (2), 1,10-phenanthroline (3), 5,6-dimethyl-1,10-phenanathroline (4), 3,4,7,8-tetramethyl-1,10-phenanthroline (5) and dipyrido-[3,2-f:2′,3′-h]quinoxaline (6), has been synthesized and their cytotoxicity in HeLa cervical cancer cells examined. In the molecular structures of 2 and 4, as determined by single-crystal X-ray studies, Cu(II) assumes a trigonal bipyramidal distorted square-based pyramidal (TBDSBP) coordination geometry. DFT studies reveal that the axial Cu–N4diimine bond length, interestingly, varies linearly with the experimental CuII/CuI reduction potential as well as the trigonality index τ of the five-coordinate complexes, and that methyl substitution on diimine co-ligands tunes the extent of the Jahn–Teller distortion at the Cu(II). While 4 is involved in strong DNA groove binding with a hydrophobic interaction of methyl substituents, 6 is involved in stronger binding through partial intercalation of dpq with DNA. Complexes 3, 4, 5, and 6 efficiently cleave supercoiled DNA into NC form in ascorbic acid by generating hydroxyl radicals. Interestingly, 4 exhibits higher DNA cleavage in hypoxic than at normoxic conditions. Notably, except for [CuL]+, all the complexes were stable in 0.5% DMSO-RPMI (without phenol red) cell culture medium up to 48 h at 37 °C. Remarkably, all the complexes show time-dependent cytotoxicity at nanomolar concentrations (IC50, 7.0–182 nM) in HeLa cervical cancer cells compared with uncoordinated ligand HL (IC50 > 10 000 nM). Except for 2 and 3, all the complexes exhibit higher cytotoxicity than [CuL]+ at 48 h. 4 shows (57.2 nM) higher cytotoxicity than 1 (181.5 nM) at 24 h incubation; however, notably, 1 demonstrates phenomenal cytotoxicity (7.0 nM) higher than 4 (13.6 nM) at 48 h incubation. The selectivity index (SI) reveals that complexes 1 and 4 are 53.5 and 37.3, respectively, times less toxic to HEK293 normal cells than to cancerous cells. Except for [CuL]+, all the complexes generate ROS to different extents at 24 h, with 1 producing the highest amount, which is consistent with their redox properties. Also, 1 and 4 exhibit, respectively, sub-G1 and G2-M phase cell arrest in the cell cycle. Therefore, complexes 1 and 4 have the potential to emerge as promising anticancer agents. [ABSTRACT FROM AUTHOR]

The title compound, [Cu(C11H15N2O)(C12H8N2)]ClO4 or [Cu(L)(phen)]-(ClO4) {where L refers to the deprotonated form of 2-[(2-dimethylaminoethylimino) methyl]phenol} and phen is 1,10-phenanthroline) is a mononuclear mixed ligand copper(II) complex. The CuII atom is coordinated by two N and one O atoms of the tridentate Schiff base ligand (HL) and two N atoms of the 1,10-phenanthroline ligand, resulting in a five-coordinate complex. The asymmetric unit of the title complex contains two crystallographically independent complex cations (a and b) with a slightly different geometry around the CuII ion. The value of the trigonality index τ, indicates that in both cations a and b, the CuII atoms display a square-pyramidal distorted trigonal-bipyramidal (SPDTBP) geometry, although the distortion is greater for cation a. [ABSTRACT FROM AUTHOR]

Copper(I) complexes of the types [Cu(N–N)(PPh3)2]NO3 (LC41–LC44) and [Cu(N–N)(PPh3)(NO3)] (LC45) carrying 3‐substituted 1‐pyridine‐2‐ylimidazo[1,5‐a]pyridine (N–N) derivatives and triphenylphosphine (PPh3) ligands have been prepared. The synthesized copper(I)–phosphine complexes were fully characterized by NMR, IR, ESI‐MS and UV–visible spectroscopy as well as by cyclic voltammetry. Selected structures such as LC42, LC43 and LC45 were additionally analysed by single‐crystal X‐ray method, which show that copper(I) centre adopts a highly distorted tetrahedral geometry. The 1H and 13C NMR spectral data of the complexes throw light on the nature of metal–ligand bonding. They display dπ–π* metal‐to‐ligand charge transfer (MLCT) transition and show quasireversible CuI/CuII metal oxidation. Among the copper(I)–phosphine complexes, LC41–LC44 exhibit moderate cytotoxicity (IC50: 24 h, 67–74 μM; 48 h, 58–70 μM) against human lung epithelial adenocarcinoma A549 cells, whereas LC45 displays the best activity (IC50: 24 h, 42 μM; 48 h, 34 μM) for A549 cancer cell line, which is better than that of the commercial antitumor drug cisplatin. All the complexes also displayed excellent selectivity by being relatively inactive against the human lung epithelial L132 normal cell line with selectivity index (SI) values ranging from 3.4 to 7.4. The complexes block cell cycle progression of A549 cells in G0/G1 phase. FACSVerse analyses are suggestive of reactive oxygen species (ROS) generation and apoptotic cell death induced by the LC41, LC43 and LC45. The induction of apoptosis in A549 cells was shown by Annexin V with propidium iodide (PI) and 4′,6‐diamidino‐2‐phenylindole (DAPI) staining methods and established the ability of LC41, LC43 and LC45 to accumulate in the cell nuclei. [ABSTRACT FROM AUTHOR]

A series of mixed-ligand Cu(II) complexes of the type: (i) [Cu(l-pro)(diimine)(H2O)n](ClO4) (n = 0 or 1), where l-pro is l-proline and diimine is 2,2′-bipyridine (bpy; 1), (ii) 4,4′-dimethyl-2,2′-bipyridine (dmbpy; 2), (iii) 1,10-phenanthroline (phen; 3), (iv) 5,6-dimethyl-1,10-phenanthroline (5,6-dmp; 4), (v) 3,4,7,8-tetramethyl-1,10-phenanthroline (3,4,7,8-tmp; 5), (vi) dipyrido-[3,2-f:2′,3′-h]-quinoxaline (dpq; 6), and (vii) dipyrido[3,2-a:2′,3′-c]phenazine (dppz; 7) have been synthesized and characterized systematically. Complexes 2 and 3 have been structurally characterized. DNA- and protein-binding and cleavage studies revealed that 7 possesses stronger DNA- and protein-binding efficiency and also exhibits self-activating DNA-cleavage in the absence of an activating agent. The hydrophobic complexes 4 and 5 induced self-activated protein cleavage and yielded a single-cleaved fragment each. The cytotoxic property of all the seven complexes was examined by incubation with the human small cell lung carcinoma cell line A549. Complexes 4 and 6 exhibited almost similar cytotoxic properties [IC50 = 1.4 µM (4) and 1.3 µM (6)], which was 9.3 and 10 times, respectively, more efficient than cisplatin (IC50 = 13 µM). Complex 4 induced generation of the highest level of intracellular ROS which correlates with its efficient cytotoxic activity and provides scope for further investigation as a potential anticancer agent. [ABSTRACT FROM AUTHOR]

Abstract : The fixation of carbon dioxide (CO2) is an important global challenge. A significant increase of the atmospheric CO2 due to the industrial emissions and a steady increase in combustion of fossil fuels is a widespread environmental concern. This article is a short literature review on the recent developments in the field of CO2 activation and fixation by bioinspired copper(II) catalysts. In our laboratory, copper(II) complexes of bidentate ligands have been reported as catalysts for the fixation of CO2. The molecular structure of one of the complexes has shown unusual trigonal bipyramid geometry (τ, 0.936) by the coordination of two ligand units and a water molecule. All the complexes exhibited a well-defined Cu(II)/Cu(I) redox potentials around 0.352 to 0.401 V in acetonitrile. The rhombic EPR spectra of the complexes indicate the existence of a geometrical equilibrium between trigonal bipyramidal and square pyramidal at 70 K. The d-d transitions around 750-800 and 930-955 nm further supports five coordination geometry in solution. These copper(II) complexes have successfully fixed atmospheric CO2 as CO32- by using Et3N as sacrificial reducing agent and afforded [Cu(L)CO3(H2O)]. The CO32- bound complex has shown a distorted square pyramidal geometry (τ, 0.369) around copper(II) center via the coordination of only one ligand unit, a carbonate, and water molecules. The catalysts are active enough to fix CO2 for eight repeating cycles without any change in the efficiency. The fixation of CO2 possibly proceeds via the formation of Cu(I)-species. This is supported by X-ray structure, which reveals distorted tetrahedral geometry by the coordination of two units of ligand.GRAPHICAL ABSTRACT: SYNOPSIS The fixation of carbon dioxide (CO2) is an important global challenge. This review summarizes the recent developments in CO2 fixation by bioinspired Cu(II) catalysts. [ABSTRACT FROM AUTHOR]

The copper(II) complexes of 1,4 diazepane based 3N-ligands have been synthesized and characterized as the novel models for lytic polysaccharides monooxygenases (LPMOs). They catalyze the oxidative cleavage of model substrate p -nitrophenyl-β-D-glucopyranoside into p -nitrophenol with higher yield (78.4%) and TON (300) in water. • Bioinspired copper(II) complexes are reported as LPMOs models. • The complexes provide structural resemblances to 'histidine brace' of LPMOs. • They showed oxidative C-O bond breakage with higher yield (78.4%) and TON (300). • The oxidative cleavage reactions occur via key intermediate CuII-OOH. Lytic polysaccharide monooxygenases (LPMOs) are copper-containing monooxygenase and catalyzing the oxidative cleavage of recalcitrant polysaccharides using dioxygen. The copper(II) complexes [Cu(L1)(H 2 O)ClO 4 ]ClO 4 1 , [L1 = 4-methyl-1-[(pyridin-2-yl-methyl)]-1,4-diazepane]; [Cu(L2)(H 2 O)ClO 4 ]ClO 4 2 , [L2 = 4-methyl-1-[(2-(pyridine-2-yl)ethyl]-1,4-diazepane] and [Cu(L3)(H 2 O)ClO 4 ]ClO 4 3 , [L3 = 1-(4-methoxy-3,5-dimethyl-pyridin-2-yl)methyl)-4-methyl-1,4-diazepane] have been synthesized and characterized as the novel models for LPMOs. The molecular structures exhibit distorted square pyramidal geometry (τ, 0.183–0.388) as similar to LPMOs. The Cu N (1.99–2.02 Å) bond distances of the model complexes are almost identical to those of native LPMOs enzyme (1.9–2.2 Å). The 1, 4-diazepane backbone and pyridine unit of complexes provide reasonable structural resemblances to 'histidine brace' and histidine residues of LPMOs respectively. The spectral, redox and kinetic studies were performed in water to mimic accurate enzymatic reaction conditions. The well-defined Cu(II)/Cu(I) reduction couples were observed around 8–112 mV versus NHE, which is lower than that of LPMOs. The electronic spectra of the complexes showed the d-d transitions around 600–635 nm and axial EPR parameter (g || , 2.28–2.29; A ||, 160–168 × 10−4 cm−1), which are almost identical to that of LPMOs. The model complexes were catalyzed oxidative cleavage of model substrate p -nitrophenyl- β -D-glucopyranoside into p -nitrophenol and D-allose with a maximum yield up to 78.4% and TON, 300. The kinetics of reaction monitored by following the formation of an absorption band around at 400 nm corresponds to p -nitrophenol, showed the rate of 3.19–5.26 × 10−3 s−1. The oxidative cleavage reaction may occur via CuII-OOH intermediate, whose formation accompanied by an electronic spectral signature around 375 nm with the rate of 1.61–9.06 × 10−3 s−1. The CuII-OOH intermediate was characterized by spectral methods and its geometry was optimized by DFT calculations. [ABSTRACT FROM AUTHOR]

• Bioinspired copper(II) complexes are reported as the model for type 2 copper site in phenoxazinone synthases. • They catalyze the conversion of the substrate 2-aminophenol into 2-aminophenoxazine-3-one using molecular oxygen in water. • Spectral, redox, and kinetic studies were performed in water to mimic accurate enzymatic reaction conditions. A new series of copper(II) complexes [Cu(L)Cl 2 ] 1 – 5 , where L is dimethyl-(2-{[(pyridin-2-ylmethyl)-amino]-methyl}-phenyl)-amine (L1); dimethyl-{2-[(2-pyridin-2-yl-ethylamino)-methyl]-phenyl}-amine (L2); 2-((3-(dimethylamino) propylamino)-methyl)- N,N -dimethylbenzenamine (L3); 2-((2-(dimethylamino) ethylamino) methyl)- N,N -dimethylbenzenamine (L4) and (2-{[(1 H -benzimidazole-2-ylmethyl)-amino]-methyl}-phenyl)-dimethylamine (L5) have been synthesized and characterized as the model for type 2 copper site in phenoxazinone synthases. The molecular structure of 1 exhibits nearly a perfect square pyramidal geometry (τ , 0.01). The complexes showed Cu(II)/Cu(I) redox potentials around −0.128 to −0.215 V in water. The electronic spectra of 1 – 5 exhibited d-d transitions around 620–643 nm in water. All the complexes exhibit almost similar electron paramagnetic resonance (EPR) parameter (g || , 2.21–2.27; A ||, 161–175 × 10−4 cm−1) corresponds to square-based geometry. The complexes have catalyzed the conversion of substrate 2-aminophenol into 2-aminophenoxazine-3-one using molecular oxygen. The formation was accomplished by appearance of a new absorption band at 433 nm with the reaction rate of 6.14–9.89 × 10−3 s−1 in water. [ABSTRACT FROM AUTHOR]

Binuclear Copper(I) Complex used for Protein binding studies. [Display omitted] • Binuclear copper (I) complex with triphenylphosphine based dithiocarbazate ligand was designed and synthesized. • The crystal structure of complex was explained. • Protein binding studies with Cu complex through absorption and fluorescence studies are discussed. A binuclear copper(I) complex with general formula [Cu(L)] 2 where L = N' -(diphenylphosphanyl-benzylidine)-hydrazinecarbodithioic acid methyl ester have been synthesized and characterized by elemental analysis, FT-IR, NMR and UV–Vis spectroscopy, mass spectrometry and single crystal X-ray diffraction. The complex crystallizes in the monoclinic space system, space group P2 1 /c. The coordination geometry around the copper(I) atom was best described as distorted square planar geometry. The binding interaction between the copper(I) complex and bovine serum albumin (BSA) was studied by absorption and fluorescence spectroscopy at room temperature. The Stern-Volmer quenching constant (Ksv), binding constant (K b), and number of binding sites (n) were determined. [ABSTRACT FROM AUTHOR]

• A series of copper(I) complexes of distorted tetrahedral coordination geometries are reported. • The complexes are emissive nature in the solid-state. • They became weak emissive or non-emissive in solution. • In solution, strong structural rearrangements are caused in excited states and it is restricted in the solid-state. A series of copper(I) complexes [Cu(L)(PPh 3) 2 ]NO 3 (1 – 5) of bidentate ligands 2-pyridin-2-yl-quinoline (L1), 4-phenyl-2-pyridin-2-yl-quinoline (L2) 2-pyridin-2-yl-quinoxaline (L3), 6,7-dimethyl-2-(pyridin-2-yl)quinoxaline (L4), and 4-phenyl-2-pyridin-2-yl-quinazoline (L5) have been synthesized and characterized by elemental analysis, absorption, emission, IR, 1H, 13C, 31P NMR spectroscopies and redox method. Of these complexes [Cu(L1)(PPh 3) 2 ]NO 3 (1) , [Cu(L3)(PPh 3) 2 ]NO 3 (3), and [Cu(L4)(PPh 3) 2 ]NO 3 (4) are structurally characterized by single-crystal X-ray analysis. They exhibited distorted tetrahedral coordination geometries around the copper(I) center with τ 4 values of 0.77–0.86. In the solid-state, all these complexes have exhibited emission in the range of 450–750 nm and their excited-state lifetimes were measured as of 1.9–8.9 μs. However, all the complexes were found to be weak emissive in solution due to the excited state structural rearrangement. Further, Time-dependent density-functional theory (TDDFT) calculations showed that the charge transfers are mainly caused by the contribution of HOMO-2 → LUMO, HOMO-1 → LUMO and HOMO → LUMO orbitals. [ABSTRACT FROM AUTHOR]

A series of new copper complexes have been synthesized and completely characterized by pivotal analytical techniques. The coordination geometry around copper(I) complex was best described as distorted tetrahedral geometry. The binding of bovine serum albumin with Cu(I) complexes are also been investigated. The Stern–Volmer analysis on quenching data exhibits the presence of the static quenching mechanism. The binding constants were calculated using modified Stern-Volmer, Lineweaver–Burk and Scatchard plots. All the complexes exhibit the binding constants in the order of 104. Thus, these results can contribute to the development of Cu(I) based drugs. • Triazine based Copper(I) Complexes were designed and synthesized. • The coordination geometry of Cu(I) complex was described as distorted tetrahedral. • The binding of bovine serum albumin with Cu(I) complexes was studied. [ABSTRACT FROM AUTHOR]