Polymeric Copper Research Articles

A polymeric copper complex based on a pyrazole derivative: Synthesis, spectroscopic, X‐ray, and biological activity studies

A novel 1D coordination polymeric copper complex based on 4‐(4′‐nitrophenylhydrazono)‐5‐trifluoromethyl‐2,4‐dihydropyrazol‐3‐one was prepared and characterized spectroscopically and thermally and via X‐ray crystallographic investigation. The prepared copper‐based structure was proved to have a 1D coordination polymer. X‐ray studies showed that the polymeric copper complex was of octahedral geometry, the ligand acted as a bidentate ligand, and the nitro group attached to the ligand acted as a bridging group. The cytotoxic activities of the copper polymer were evaluated including against MCF‐7 cells (breast cancer cell line), HepG‐2 cells (hepatocellular carcinoma), and HCT‐116 cells (colon cancer cell line). The morphological alterations of the complex treated cells were investigated using an inverted microscope. The cell cycle and apoptosis were evaluated and reported. The copper polymer exhibited the best antitumor activity against HepG‐2 cells (35.22 ± 4.80 μM) while also causing a decline in the G2/M phase and a remarkable enhancement in the early apoptosis.

A novel μ3-CO3 bridged linear polymeric Cu-complex ([Cu3(DMAP)8(μ3-CO3)2]I2) n ·xH2O: synthesis, characterization and catalytic applications in the synthesis of phenoxypyrimidines and arylthiopyrimidines via C-O and C-S cross-coupling reactions.

This manuscript reports on the synthesis and characterization of a new polymeric copper complex ([Cu3(DMAP)8(μ3-CO3)2]I2) n ·xH2O and its successful application in C-O and C-S cross coupling reactions for the synthesis of biologically important phenoxypyrimidine and arylthiopyrimidine scaffolds. In an attempt to synthesize [Cu(DMAP)4I]I by adopting a procedure reported by Roy et al. with slight modification, the authors discovered a new polymeric Cu-complex that contains μ3-CO3 bridges. The polymeric linear structure of the complex was established using single crystal X-ray analysis. FT-IR, UV-vis and DSC studies were also performed on the polymeric complex. This novel polymeric Cu-complex was found to efficiently catalyse C-O/C-S cross coupling reactions between chloropyrimidines and phenols/thiophenols in an aqueous medium within a short reaction time, delivering their corresponding phenoxypyrimidines and arylthiopyrimidines. Using this protocol, 22 phenoxypyrimidines and 6 arylthiopyrimidines were successfully synthesized. The synthesized novel compounds were well characterized using 1H and 13C NMR spectroscopy and HRMS analysis and were screened for their drug-likeness properties using the SwissADME webtool.

Polymeric Copper Chelator for Long-term Inhibition of Breast Cancer Proliferation and Lung Metastasis

Polymeric Copper Chelator for Long-term Inhibition of Breast Cancer Proliferation and Lung Metastasis

New Polynuclear Coordination Compounds Based on 2–(Carboxyphenyl)iminodiacetate Anion: Synthesis and X-rays Crystal Structures

In the present work, novel polymeric copper(II) coordination compounds, namely [Cu2(cpida)(H2O)4][Cu(cpida)]·3H2O (1) (cpida3− = 2-(carboxyphenyl)iminodiacetate anion) and Na[Cu(cpida)] (3), were synthesized and characterized using infrared spectroscopy, thermogravimetric analysis, elemental analysis, and single-crystal X-ray diffraction. Compound 1 was obtained by slowly evaporating an aqueous solution of H3cpida, copper(II) sulfate, and NaOH at room temperature. The structural characterization revealed that 1 is an ionic entity formed by the [Cu(cpida)]− anion and the [Cu2(cpida)(H2O)4]+ cation, both of polymeric 1D structure. Compound 3 was prepared under similar conditions from copper perchlorate and crystallized via acetone diffusion. It is a coordination polymer formed by the [Cu(cpida)]− units, and the sodium cation is present in the structure, counterbalancing the anion charge. Depending on the crystallization conditions, it was possible to obtain other solvation forms of these structures. Starting from the conditions of compound 1, via the diffusion of ethanol, [Cu2(cpida)(H2O)4][Cu(cpida)]·H2O·1/2EtOH (2) was precipitated, while a hydrate form of compound 3 with the formula Na[Cu(cpida)]·2H2O (4) was obtained via methanol diffusion.

One-dimensional polymer of copper with salicylic acid and pyridine linkers: Synthesis, characterizations, solid state assembly investigation by hirshfeld surface analysis, and computational studies

A new one-dimensional polymeric copper complex [Cu(DNSA)py] with salicylic acid and pyridine was synthesized and characterized by many techniques, including FT-IR, UV–Visible, elemental, TGA/DSC, and single crystal XRD analysis. In the crystal structure, two 3,5-dinitrosalicylic ligands were chelated by the copper cation, in which one ligand was coordinated by the carbonyl O-atom and one of the carboxylate O-atoms, while another symmetry-related ligand was coordinated by the O-atoms of the carboxylate group to form distorted square pyramidal geometry. Thus, a one-dimensional polymer structure is formed, extending along the b-axis. The solid-state assembly was stabilized by various intermolecular interactions, as examined through Hirshfeld surface analysis. Voids analysis was carried out to predict the response of the crystal under external pressure. The most stable structure of the [Cu(DNSA)py] monomer resulted from density functional theory (DFT) using the B3LYP/def2-TZVPP. The 6–311G(d,p) level of theory demonstrated that the Cu atom adapts distorted square pyramidal geometry. The MEP surface and Mulliken charge distribution identified the Cu monomer atoms suitable for electrophilic and nucleophilic attacks. Frontier molecular orbital (FMO) analyses were conducted to anticipate the stability and chemical reactivity of the [Cu(DNSA)py] monomer and its ligand (DNSA). Furthermore, the quantum chemical descriptors of the title compound were obtained from EHOMO and ELUMO energy values.

Polymeric copper(I)-NHC complexes with bulky bidentate (N^C) ligands: synthesis and solid-state luminescence.

Starting from imidazolium chlorides bearing bulky nitrogen donors, a series of four complexes, mainly [Cu(C^N)Cl]n coordination polymers were obtained directly as luminescent species by simple filtration from the aqueous reaction medium, highlighting a simple, eco-friendly, robust and reproducible synthetic procedure. Additionally, we have shown on the most efficient example that chloride could be exchanged very easily by other halides/pseudohalides (Br-, I-, NCS-, N3-) allowing to slightly modulate the emitted colour while conserving the polymeric structure, except for azide for which a dimer was obtained. The combination of chemical analyses, of photoluminescence studies in the solid state including quantum yield measurement and X-ray diffraction on single crystals and as-synthesized microcrystalline powders highlighted that the polymeric luminescent species was indeed obtained directly by simple filtration and that no major alteration of the structure was observed upon recrystallisation. Samples of all polymeric complexes displayed remarkable stability towards air oxidation remaining unchanged upon storage for several months and partially retaining their photoluminescence properties even after a thermal treatment at 100 °C for 24 h.

Polymeric copper(ii) and dimeric oxovanadium(v) complexes of amide-imine conjugate: bilirubin recognition and green catalysis.

An exceptionally simple amide-imine conjugate, (E)-N'-(4-(diethylamino)-2-hydroxybenzylidene)-4-methylbenzohydrazide (L), derived by the condensation of 4-methyl-benzoic acid hydrazide (PTA) with 4-(diethylamino)-2-hydroxybenzaldehyde was utilized to prepare a dimeric oxo-vanadium (V1) and a one-dimensional (1D) copper(ii) coordination polymer (C1). The structures of L, V1 and C1 were confirmed by single crystal X-ray diffraction analysis. The experimental results indicate that V1 is a promising green catalyst for the oxidation of sulfide, whereas C1 has potential for a C-S cross-coupling reaction in a greener way. Most importantly, C1 is an efficient 'turn-on' fluorescence sensor for bilirubin that functions via a ligand displacement approach. The displacement equilibrium constant is 7.78 × 105 M-1. The detection limit for bilirubin is 1.15 nM in aqueous chloroform (chloroform/water, 1/4, v/v, PBS buffer, and pH 8.0).

Ligands containing 7-azaindole functionality for inner-sphere hydrogen bonding: Structural and photophysical investigations

The synthesis, structural analysis and spectroscopic characterisation of three new 7-azaindole ligands is reported, alongside a novel 7-azaindole derived coordination polymer, with the aim of identifying new bridging ligands containing inner-sphere hydrogen bond donor functionality. Structural characterisation shows that the 7-azaindole hydrogen bond donor ability is significantly stronger in the hydrazone and imine species 1 and 2 compared to the amine 3, with the opposite trend evident in their hydrogen bond acceptor character. These findings are mirrored by the fluorescence spectroscopy results which show bimodal emission, characteristic of multiple emissive species related by proton transfer, is only evident in the amine species and not the more acidic imines. The polymeric copper(II) complex of the hydrazone ligand 1 shows the anticipated inner-sphere hydrogen bonding with a similar donor strength to that observed in the free ligand, which leads to deformation in the remainder of the coordination sphere. These results show the untapped versatility of the 7-azaindole functional group as a building block for ligands in coordination polymers and other multinuclear assemblies, with the potential for both stabilisation through hydrogen bonding and interesting photophysical properties.

Square-pyramidal mononuclear, dinuclear and polymeric copper(II) complexes with (2-pyridinylmethyl)amino derivatives

The coordination behavior of three ligand precursors 2-[(2-pyridinylmethyl) amino]acetic acid hydrochloride, 4-[(2-pyridinylmethyl)amino]benzoic acid hydrochloride and 4-{[2-(pyridin-2-ylmethylamino)ethylamino]methyl}- benzoic acid hydrochloride, HL1?HCl?HL3?HCl, respectively, in copper(II) complexes is described. The complexes were characterized by elemental analysis, ESI mass spectrometry and IR spectroscopy, as well as X-ray structural analysis. The reaction of copper(II) with HL1?HCl in methanol afforded the polymeric complex [{Cu(?-Cl)2(MeL1-?2N,N?)}n] (1) featuring the methyl ester of L1 (MeL1). With HL2?HCl or HL3?HCl, the dimeric complex [{CuCl(?-Cl)(HL2-?2N,N?)}2] (2) or the mononuclear complex [CuCl2(HL3- ?3N,N?,N??)] (3) were obtained. All complexes exhibited square-pyramidal geometries. In 1, polymeric chains are formed through bridging chlorido ligands without typical hydrogen bonding interaction. Contrarily, the COOH group in 2 is participating in the formation of intermolecular hydrogen bonding forming a supramolecular structure. In 3, intermolecular hydrogen bonding (Cl???H(O)) leads to a 1-D polymeric structure. The copper(II) complex 2 diminished viability of human 8505C, MCF-7, 518A2 and SW-480 cell lines. The tumoricidal effect of 2 was realized mainly through caspase-mediated apoptosis.

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

This work highlights the applications of polymeric copper complex in the synthesis of amides and triazole containing amides.

Polymeric Copper(II) Complexes with a Newly Synthesized Biphenyldicarboxylic Acid Schiff Base Ligand—Synthesis, Structural and Thermal Characterization

The newly synthesized biphenyldicarboxylic acid Schiff base and its complexes with Cu(II) were synthesized, and their spectroscopic and structural analysis was performed. The reaction of the ligand and copper(II) acetate in different solvents resulted in the formation of two solvatomorphic complexes, one with MeOH, and the other with DMF molecules, in the crystal lattice. The differences in the results of the thermal analysis could be explained by the different polarities of the solvents present. SC-XRD analysis revealed that the ligand is coordinated as a dianion, in a pentadentate manner, through two phenoxide oxygen atoms, two azomethine nitrogen atoms, and with the oxygen atom of one carboxylate functioning as a bridge that connects the monomeric units. The coordination polyhedron was described with several parameters obtained from different methods of calculation. The presence of different solvents in the crystal structure results in differences in the H-bond networks, and an overall different crystal packing of the structural units in the obtained complexes.

Asymmetric Alkylation of α,β-Unsaturated Ketones or Imines on a Polymeric Copper Catalyst

Key words copper catalysis - asymmetric catalysis - alkylation - ketones - imines - dialkylzinc

Selective CO2 Adsorption at Low Pressure in Nitrogen‐Rich Copper(II) Coordination Polymers

AbstractHerein, a series of polymeric copper(II) complexes were obtained using four different triazoles: 3‐amino‐1,2,4‐triazole (HL1), 3,5‐diamino‐1,2,4‐triazole (HL2), 3‐amino‐1,2,4‐triazole‐5‐carboxylic acid (H2L3) and 1,2,4‐triazole‐3‐carboxylic acid (H2L4); through solvothermal conditions, under controlled pressure and high temperature, following usual procedures described in the literature. These triazoles were chosen to exploit their different coordination modes to copper(II) metal centres to obtain interesting structures and varied gas adsorption selectivity. The isolated materials were characterized by common spectroscopic techniques (IR, diffuse reflectance UV‐Vis, EPR), CHN analyses, X‐ray diffraction (XRD), thermogravimetric analyses, and SQUID magnetometry to give an insight into their structure and composition. Besides, they had their BET surface area determined by nitrogen adsorption‐desorption isotherms, to assess their porosity. At last, their capacity to adsorb carbon dioxide selectively was also evaluated, in line with those reported for similar systems in the literature. Although having small surface area, these compounds are able to adsorb CO2 selectively at very low pressure (under 600 mbar).

In vitro DNA interaction, topoisomerase I/II Inhibition and cytotoxic properties of polymeric copper(II) complex bridged with perchlorate ion containing N4-type schiff base ligand

Cu(II) complex containing p-Cl-isonitrosoacetophenone based on N4-type Schiff base ligand was synthesized and characterized by elemental analysis, FTIR, 1H NMR, 13C NMR and UV-Visible. The crystal structure of the synthesized complex was determined by single crystal X-ray analysis. In the crystal structure, the intermolecular hydrogen bonds link the one dimensional polymers into a network structure, in which they may be effective in the stabilization of the structure. The binding profile of the complex with CT-DNA was carried out by absorption spectra and fluorescence measurements. The experimental results were revealed that binding of the complex with CT-DNA via intercalation. The concentration and time dependent DNA cleavage studies including cleavage mechanism of the complex was performed by employing gel electrophoresis assay, where the complex has been found to cleave supercoiled DNA with high efficiency. Topoisomerase I and IIα inhibition assays with Cu(II) complex were performed. Complex showed strong inhibition against both enzymes at 5 µM. The cytotoxic activity of the complex was performed on human cell lines, breast cancer MDA-MB-231, lung carcinoma A549, colorectal adenocarcinoma HT29, neuroblastoma SH-SY5Y and normal cell line HEK-293 by MTT assay. The complex was exhibited remarkably good cytotoxic potential on cancer cell lines HT29 and SH-SY5Y.

Comprehensive structural {single crystal X-raydiffraction, spectroscopic & DFT computational simulation} and biological {in vitro DNA binding & antibacterial} studies of polymeric copper(Ⅱ)-based imidazole drug entity

A polymeric tetrakis N-imidazole copper(II) sulphate complex [Cu(imidazole)4(SO4)]n1, was synthesized and thoroughly characterized by various spectroscopic techniques, elemental analysis and single crystal X-ray crystallography. X-ray diffraction analysis confirmed that polymer complex 1 crystallized in a monoclinic C2/c space group possessing the lattice constants, a = 9.2213(1) Å, b = 17.6062(3) Å, c = 10.5710(2) Å, α = γ = 90˚ and β = 93.561˚ (1) per unit cell. Hirshfeld surface and DFT calculations were executed to simulate the electronic ground state energies in gas phase which showed that the HOMO and HOMO–1 were distributed on the axially coordinated SO42– moiety and considerable amount of electron density was present on Cu(II). Absorption and emission spectroscopic techniques were used to investigate the binding interaction of the copper(II) imidazole complex with the therapeutic target ct-DNA. The results suggested that the complex 1 binds to the ct-DNA through an electrostatic mode. The gel electrophoresis experiments of 1 were carried out with plasmid pBR322 which revealed that the polymer complex could unwind the plasmid DNA at 30 μM micromolar concentration via discernible oxidative cleavage pathway. Molecular docking studies were also carried out to support the results of DNA binding experiments. In addition, the antimicrobial potential of polymer complex was evaluated against various key pathogens viz., B. subtilis, E. coli, K. pneumonia and S. aureus. Antibiofilm behaviour of the complex 1 was examined against E. coli and S. aureus. The results demonstrated that 1 could act as an active antibacterial agent as it inhibited the bacterial growth in agar plates very efficiently.

Synthesis, characterization, spectral studies and evaluation of noncovalent interactions in co-crystal of μ-oxobridged polymeric copper(II) complex derived from pyrazolone by theoretical studies

The new co-crystal of μ-oxobridged polymeric copper(II) complex {[0.714(9) CuII2(HL-CH2OH)2].[0.286(9) CuII2(HL-CHO2H)2]}n with Schiff base ligand derived from pyrazolone, (HL = 4-[(2-hydroxy-3-methoxybenzylidene)amino-1,5-dimethyl-2-phenyl-1H-pyrazol-3-one), was synthesized and characterized by spectral and analytical techniques. The optimal and unexpected quality structures of the copper (II) polymer complex were determined using X-ray. Crystals are monoclinic, a = 7.8472(2), b = 12.5860(3), c = 17.0842(3) Å, β = 97.140(2)° and space group P21/c. The complexes are 4 + 1 coordinated, with four standard coordination distances in a square-planar geometry and a fifth, longer, secondary coordination distance at the square pyramid's apex. The basic complexes have a Ci-symmetrical Cu2L2 composition and extend into polymeric chains along the x crystallographic axis due to the longer contact. The electrochemical properties of complex in DMSO displayed the electronic effects on the groups on redox potential. The density functional theory by B3LYP method with (6-311 G) basis set was used to optimize the molecular geometry of the copper complex. Following the optimized DFT, FT-IR spectroscopy was used to determine geometric characteristics such as bond length and bond angle, which were then compared to experimental data. The intermolecular interactions were characterized using X-ray crystal structure analysis, HS (Hirshfeld surface analysis) and FPs (fingerprint diagrams). In addition, QTAIM (Quantum Theory of Atoms in Molecules) analysis was studied to determine the type of bonds and the energies of the metal-ligand bond. The adsorption process of complexes (1) and (2) in the aqueous phase on graphene oxide (GO) was calculated by the Monte Carlo adsorption locator. The results showed complex (2) had a high binding efficiency on GO compared with complex (1). The molecular docking study was also carried out for the copper complex to find its binding affinity to protein B-cell lymphorna (BCL-2, PDB ID: 4LXD).

Synthesis and Structure of Polymeric Copper(I) Compound with Single-Stranded Dihelicate Units involving Multiring Nitrogen-Heterocyclic Ligand

The polymeric copper(I) complex [Cu2(L)I2] (1) containing a new biologically relevant heterocyclic bis-bidentate ligand viz. 3,3′-dipyridine-2-yl-[1.1′]bi[imidazo[1,5-a]pyridineyl] (L) was synthesized and characterized by single-crystal X-ray diffraction analysis. The molecule lacks molecular center of symmetry where coordination environments around both Cu(1) and Cu(2) are distorted tetrahedral (Cu···Cu# separation of 3.5 Å). Compound in its solid-state structure shows π-π non-covalent interactions as well as Carene-H---anion non-classical hydrogen bonding interactions that play dominant roles in shaping the extended structure of the molecule.

Synthesis, crystal structure and antimicrobial activity of a new polymeric copper(II) complex derived from N'-(pyridin-2-ylmethylene)isonicotinohydrazide

A new polymeric copper(II) complex [Cu3L3(μ3-NO3)]n·2nNO3, derived from the Schiff base ligand N'-(pyridin-2-ylmethylene)isonicotinohydrazide (HL) with copper nitrate in methanol, was prepared and characterized by elemental analysis, IR and UV-Vis spectra. The structure of the complex was further confirmed by single crystal X-ray diffraction technique. The Schiff base ligand coordinates to the Cu atoms through the phenolate O, imino O, and two pyridine N atoms. The Cu atom is in a square pyramidal coordination, with the three chelate donor atoms of the Schiff base ligand and the terminal nitrogen donor atom of a symmetry related Schiff base ligand defining the basal plane, and with one oxygen atom of the coordinated nitrate ligand at the apical position. The nitrate ligand bridges three [CuL] units with a crystallographic three fold rotation axis symmetry. The effect of the complex on the antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans was studied.

Copper(II) complexes with NNN and NNO Schiff base ligands as efficient photodegradation agents for methylene blue, preferential BSA binder and biomaterial transplants

Herein, a monomeric copper(II) complex of the general formula [Cu(L)Cl2] (1) and a polymeric copper(II) complex bearing the formula [Cu2L/2(µ-N3)(N3)]n, (2) have been synthesized using NNN and NNO tridentate Schiff base ligands, L and L/ where L = N-((6-methoxypyridin-2-yl)methylene)(piperidin-2-yl)methane amine and L/ = 1-((3-(methylamino)propylimino)methyl)naphthalene-2-ol. Both the complexes have been characterized by single crystal X-ray diffraction and UV–Vis, FTIR, ESI-MS spectroscopic studies. The crystal structure of the complex (1) reveals a square pyramidal geometry whereas the structure of the complex (2) exhibits elongated square pyramidal geometry and the asymmetric unit of the complex contains two Cu(II) ions connected by the single µ-azido bridge. The electronic structures of the complexes are optimized by Density Functional Theory (DFT) calculations to explore their coordination stabilities and chemically reactive parameters. Besides, the Hirshfeld surfaces and two-dimensional fingerprint plot are also carried out to visualize the intermolecular interactions in the crystal of complex 1 and complex 2. Photodegradation against Methylene Blue (MB) proves the greater efficiency of complex 2 as a photodegradation agent for MB organic pollutant dye. Preferential binding studies of both the complexes towards the protein, Bovine Serum Albumin (BSA), by a series of spectroscopic techniques reveal that complex 1 strongly interacts with BSA. The spectroscopic data are well correlated by molecular docking studies. These interaction studies prompted us for cell viability studies against SiHa cancer cell to check whether the complexes may be used as biomaterial transplants or not. It is observed that the cell viability increases with time demonstrating the biocompatible nature of the complexes as well as their uses as biomaterial transplants.

Syntheses, Crystal Structures and Antimicrobial Property of Schiff Base Copper(II) Complexes

Four new copper(II) complexes, [CuL1(?1,1-N3)]n (1), [CuL1(?1,3-NCS)]n (2), [Cu(HL2)2](SCN)2 (3) and [Cu(L2)2] (4), where L1 and L2 are 2-((2-(dimethylamino)ethylimino)methyl-4,6-difluorophenolate and 2,4-difluoro-6-((3-morpholinopropylimino) methyl)phenolate, respectively, and HL2 is 2-((2-(dimethylammonio)ethylimino)methyl-4,6-difluorophenolate, were synthesized and characterized by elemental analysis, IR and UV-vis spectroscopy. The structures for the complexes were further confirmed by single crystal X-ray structure determination. Complexes 1 and 2 are polymeric copper(II) complexes, with the Cu atoms in square pyramidal coordination. Complexes 3 and 4 are mononuclear copper(II) complexes, with the Cu atoms in square planar coordination. The complexes were assayed for their antimicrobial properties.