Search

Abstract: Four N,O‐bidentate chelating ligands [L1=N‐(4‐thiazolylmethyl)morpholine‐N‐oxide, L2=N‐(2‐pyridylmethyl)pyrrolidine‐N‐oxide, L3=N‐(4‐thiazolylmethyl)pyrrolidine‐N‐oxide, and L4=N‐(2‐pyridylmethyl)morpholine‐N‐oxide] were designed and synthesized. The treatment of N,O‐bidentate ligands with CuCl2 in ethanol at room temperature afforded four new copper complexes—[Cu(L1)2]Cl2 (I), [Cu(L2)2][CuCl4] (II), [Cu(L3)2Cl]2[CuCl2(H2O)2]Cl2⋅10 H2O (III) and [Cu(L4)2][Cu(L4)2(CH3OH)2][CuCl4]2 (IV)—which were fully characterized by single‐crystal X‐ray diffraction, IR spectroscopy and elemental analyses. Most interestingly, the single‐crystal X‐ray diffraction analyses revealed that the N,O‐bidentate ligands L1–L4 can tune the corresponding geometry configuration of copper atoms in complexes I–IV. The copper atoms in I and II showed four‐coordinated distorted square planar geometry, whereas the central copper atom in III adopted a distorted square pyramidal geometry. It should be noted that complex IV was constructed by a distorted square planar CuN2O2 unit, one octahedral CuN2O4 unit and two [CuCl4]2− anions. Importantly, these copper(II) complexes, especially complex IV, showed high catalytic activity in Chan–Lam coupling reactions of primary or secondary amines with arylboronic acid under mild conditions. Substrates with many functional groups were tolerated and the C–N coupling products were afforded in good to excellent yields (up to 96 % yield). [ABSTRACT FROM AUTHOR]

Abstract: Nicotinamide has been employed as a supramolecular reagent in the synthesis of ten copper(II) chloro-, bromo-, fluoro-, iodo-, and dichlorobenzoate complexes. Compound structures were determined by single-crystal X-ray diffraction structural analysis. All ten compounds are monomeric complexes with a square-bipyramidal coordination sphere around the Cu2+ ion. The two polymorphs of [Cu(2,6-Cl2bz)2(nia)2] are examples of coordination compounds which are conformation and supramolecular isomers. The molecules of all compounds are connected by N-H…O and O-H…O hydrogen bonds from NH2 groups of nicotinamide and water molecules which create supramolecular hydrogen-bonding-coordination chains and networks.Graphical abstract: [ABSTRACT FROM AUTHOR]

This work presents a combined experimental and theoretical study of two new metal-carboxylate coordination compounds. These complexes were prepared from (1-methyl-1 H -benzimidazol-2-yl)methanol under mild conditions. The structures of the prepared compounds were characterized by single-crystal X-ray analysis, FTIR and UV–Vis spectroscopy. In the Cupper complex, the Cu(II) ion is coordinated by two ligands, which act as bidentate chelator through the non-substituted N and O atoms, and two carboxylicg oxygen atoms, displaying a hexa-coordinated compound in a distorted octahedral geometry, while in the Zinc complex the ligand is ligated to the Zn(II) ion in monodentate fashion through the N atom, and the metal ion is also bonded to carboxylic oxygen atoms. The tetra-coordinated compound displays a distorted tetrahedral shape. The density functional theory calculations are carried out for the determination of the optimized structures. The electronic transitions and fundamental vibrational wave numbers are calculated and are in good agreement with experimental. In addition, the ligand and its Cu(II) and Zn(II) complexes were screened and evaluated for their potential as DPPH radical scavenger. [ABSTRACT FROM AUTHOR]

The interaction of 5-methyl-2-phenyl-4-[(8-quinolylhydrazono)]pyrazol-3-one ( 2 ) and 5-methyl-2-phenyl-4-(8-quinolylhydrazono)pyrazole-3-thione ( 4 ) with copper(II) acetate monohydrate under reflux in ethanol results in the formation of copper(II) azo chelates incorporating CuN 4 O 2 ( 5 ) and CuN 3 S 2 ( 6 ) chromophores. All the compounds were characterized with FT-IR, EPR, X-ray absorption spectroscopy and magnetic measurements. The structures of complexes 5 and 6 were determined by X-ray single-crystal diffraction. Complex 5 adopts a pseudo-octahedral geometry with a cis disposition of the oxygen atoms around the copper(II) centre, whilst in 6 the copper(II) ion displays a square-pyramidal geometry with a {N 3 S 2 } ligand environment. [ABSTRACT FROM AUTHOR]

Four new complexes, [Cu 9 L 6 ( µ 3 -ClO 4 ) 2 ](ClO 4 ) 4 ·4CHCl 3 1 , [Cu 3 L 2 (H 2 O) 2 ](ClO 4 ) 2 ·3H 2 O 2 , [Cu 6 L 4 (N 3 ) 2 ](ClO 4 ) 2 3 and [Cu 2 L(CH 3 COO) 2 ] 4 , where H 2 L stands for the Schiff base N , N ′-bis[(2-hydroxybenzilideneamino)-propyl]-piperazine, were obtained and structurally characterized. Compounds 1 , 2 and 3 contain the Cu 3 L 2 2+ entities in which L 2− acts in an unsymmetrical mode with N 3 O donor set wrapped around marginal copper(II) and with the remained NO sets bound to the central copper ion. The marginal copper(II) ions are in distorted square pyramidal environment, whereas that of the central one is square planar. In 1 , the peripheral copper(II) ions (Cu1) are disposed linearly with a two-fold axis passing through the central Cu2 and with the Cu1⋯Cu2 and Cu2⋯Cu1′ distances of 6.755 Å. The linear trinuclear units are bridged by a rare µ 3 -1,2,3 perchlorate ligand thus describing a 2D network. In [Cu 3 L 2 (H 2 O) 2 ](ClO 4 ) 2 ·3H 2 O, the Cu 3 L 2 2+ unit is capped by two water molecules. Here, due to the intramolecular hydrogen bonds, the metal ions are disposed in the corner of a triangle with the Cu1⋯Cu2, Cu1⋯Cu3 and Cu2⋯Cu3 distances of 5.976, 5.314 and 5.760 Ǻ, respectively. In [Cu 6 L 4 (N 3 ) 2 ](ClO 4 ) 2 , two Cu 3 L 2 2+ units are bridged by two azido groups thus forming a macrocycle of six copper(II) ions. In [Cu 2 L(CH 3 COO) 2 ], L 2− acts as a symmetrical binucleatig ligand through the two N 2 O sets disposed on each side of the piperazine ring and pointed away in opposite directions. The square pyramidal environment of copper is achieved by chelate acetato co-ligand. [ABSTRACT FROM AUTHOR]

The present study reports the synthesis and evaluation of nonlinear optical property and G-Quadruplex DNA Stabilization of five novel copper(II) mixed ligand complexes. They were synthesized from copper(II) salt, 2,5- and 2,3- pyridinedicarboxylic acid, diethylenetriamine and amide based ligand (AL). The crystal structure of these complexes were determined through X-ray diffraction and supported by ESI-MAS, NMR, UV–Vis and FT-IR spectroscopic methods. Their nonlinear optical property was studied using Gaussian09 computer program. For structural optimization and nonlinear optical property, density functional theory (DFT) based B3LYP method was used with LANL2DZ basis set for metal ion and 6-31G ∗ for C,H,N,O and Cl atoms. The present work reveals that pre-polarized Complex-2 showed higher β value (29.59 × 10 −30 e.s.u) as compared to that of neutral complex-1 (β = 0.276 × 10 −30 e.s.u.) which may be due to greater advantage of polarizability. Complex-2 is expected to be a potential material for optoelectronic and photonic technologies. Docking studies using AutodockVina revealed that complex-2 has higher binding energy for both G-Quadruplex DNA (−8.7 kcal/mol) and duplex DNA (−10.1 kcal/mol). It was also observed that structure plays an important role in binding efficiency. [ABSTRACT FROM AUTHOR]

Three novel copper(II) complexes, [Cu(Gly‐ l‐Val)(HPBM)(H2O)]·ClO4·H2O (1), [Cu(Gly‐ l‐Val)(TBZ)(H2O)]·ClO4 (2) and [Cu(Gly‐ l‐Val)(PBO)(H2O)]·ClO4 (3) (Gly‐ l‐Val = glycyl‐ l‐valine anion, HPBM = 5‐methyl‐2‐(2′‐pyridyl)benzimidazole, TBZ = 2‐(4′‐thiazolyl)benzimidazole, PBO = 2‐(2′‐pyridyl)benzoxazole), have been prepared and characterized with elemental analyses, conductivity measurements as well as various spectroscopic techniques. The interactions of these copper complexes with calf thymus DNA were explored using UV–visible, fluorescence, circular dichroism, thermal denaturation, viscosity and docking analyses methods. The experimental results showed that all three complexes could bind to DNA via an intercalative mode. Moreover, the cytotoxic effects were evaluated using the MTT method, and the antimicrobial activity of these complexes was tested against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. The results showed that the activities are consistent with their DNA binding abilities, following the order of 1 > 2 > 3. [ABSTRACT FROM AUTHOR]

Reaction of sodium (E/Z)-2-(2-(1-cyano-2-methoxy-2-oxoethylidene)hydrazinyl)benzene-sulfonate (NaHL) with copper(II) nitrate hydrate in the presence of imidazole (im) in methanol affords [CuL(im)(H 2 O)] ( 1 ). Complex 1 is characterized by IR spectroscopy and ESI-MS spectrometry, elemental and single crystal X-ray crystal structural analyses. The coordination environment of the central copper(II) is nearly intermediate between ideal square-based pyramidal and trigonal bipyramidal geometry, three sites being occupied by the L 2− ligand, which chelates in the O, N, O fashion, while two other sites are filled with the water and imidazole molecules. Extensive intermolecular hydrogen bonds between the L 2− , water and imidazole ligands lead to a 3D supramolecular network. 1 and known Cu(II) complexes [Cu(H 2 O) 2 L]·H 2 O ( 2 ), [Cu(H 2 O)(py)L]·H 2 O ( 3 ) and [Cu 3 (µ 3 -OH)(NO 3 )(CH 3 OH)(µ 2 -X) 3 (µ 2 -HL)] ( 4 ) act as effective catalysts in the oxidation of cyclohexane to cyclohexanol and cyclohexanone, using low power microwave (MW) irradiation, under mild conditions. Without a promoter, the activity of the catalyst reached a turnover number of 1.44 × 10 3 and a turnover frequency of 1.98 × 10 3  h −1 , after 2 h, at 50 °C. [ABSTRACT FROM AUTHOR]

Four new water soluble chromone appended copper(II) complexes of the type [Cu(L)Cl] were synthesized from CuCl 2 ·2H 2 O and 3-formylchromone-4 N -substituted thiosemicarbazones ( HL1–HL4 ). Characterization of the compounds was done by using analytical and spectral techniques such as elemental analyses, IR, UV–Visible, EPR and Mass spectrometry, which confirmed their formation. Single crystals suitable for X-ray diffraction were obtained for complex [Cu(L4)Cl], in which the ligand coordinated in a tridentate monobasic ONS donor fashion. The compounds strongly bound to CT-DNA (Calf Thymus DNA) through intercalation. BSA (Bovine Serum Albumin) and HSA (Human Serum Albumin) binding studies were carried out to check the binding ability of the compounds with protein and the mechanism of quenching was found to be static. The occurrence of microenvironmental change in protein was further confirmed by three dimensional (3D) fluorescence experiments. DNA cleavage experiments of the complexes showed that the complexes cleaved supercoiled DNA pBR322 without any external agent. The complexes have shown significant growth inhibitory activity against selected types of bacteria namely S. aureus , S. pneumonia , P. auroginosa , S. paratyphi and fungi namely C. albicans, T. rubrum, A. niger, A. fumigatus and C. tropicalis . Tests on cell proliferation of human lung cancer cell line (A549) and human breast cancer cell line (MCF-7) were performed for all the compounds. The new water soluble complexes overcome cisplatin resistance in the MCF-7 and A549 cell lines. All the compounds were found to be non-toxic against human normal keratinocyte cells (HaCaT). The biological studies indicated that the complex [Cu(L3)Cl] ( 3) exhibited better activity among the compounds and the complexes exhibited biological activity in the following order [Cu(L3)Cl] ( 3)  > [Cu(L2)Cl] ( 2)  > [Cu(L1)Cl] ( 1 ) > [Cu(L4)Cl] ( 4) . [ABSTRACT FROM AUTHOR]

By the reactions of copper(II) nitrate with N -alkyliminodiacetamide derivatives, RN(CH 2 CONH 2 ) 2 (Rimda; R = Me (methyl), Et (ethyl), Pr (propyl) and Bu (butyl)), four new water-soluble copper(II) complexes were synthesized, namely [Cu(Meimda) 2 ](NO 3 ) 2 ( 1 ), [Cu(Etimda) 2 ](NO 3 ) 2 ( 2 ), [Cu(Primda) 2 ](NO 3 ) 2 ( 3 ) and [Cu(Buimda) 2 ](NO 3 ) 2 ( 4 ). The complexes were characterized by infrared and UV/Vis spectroscopy and thermal analysis (TG/DTA). The molecular and crystal structures of 1 and 4 were determined by X-ray crystallography. The octahedral coordination environment around the copper(II) ion consists of two O,N,O' -tridentate N -alkyliminodiacetamide ligands and the complexes are trans -isomers with fac -configuration of the chelators. Various hydrogen bond ring motifs e. g. R 2 4 (8), R 4 4 (12), R 2 1 (5), R 2 2 (8) and R 3 4 (16) were established in the crystal structures of 1 and 4 . The molecular geometry and infrared spectra of the complex cations [Cu(Meimda) 2 ] 2+ , [Cu(Etimda) 2 ] 2+ , [Cu(Primda) 2 ] 2+ and [Cu(Buimda) 2 ] 2+ were also studied by DFT calculations using BP86, B3LYP and B97-D computational models. Their calculated spectra and molecular geometries agree very well with the experimental results. The complexes were tested for possible antibacterial and antifungal activity on bacteria ( Escherichia coli and Staphylococcus aureus ) and fungi ( Candida albicans ), respectively, and showed low or negligible activity. The complexes also showed relatively high toxic effects on Lemna minor L. (duckweed), a model aquatic organism used to test the toxic effects of metal ions. [ABSTRACT FROM AUTHOR]

Two new copper (II) complexes, [Cu( N -Metn) 2 Cl]BF 4 ( 1 ) and [Cu(Me 2 tn) 2 (N 3 )]N 3 ( 2 ) ( N -Metn = N -methyl-1,3-propanediamine; Me 2 tn = 2,2-dimethyl-1,3-propanediamine), have been prepared, fully characterized, and their structures established by X-ray single-crystal analysis from synchrotron diffraction data. For these complexes, the Cu(II) ions are five-coordinate in an axially elongated square-pyramidal environment, with the four amine N atoms at the equatorial positions and the Cl atom ( 1 ) or N atom of one azide ( 2 ) at an apical site. The Cu N bond lengths for amine N atoms in the complex 1 (2.0198(13)–2.0735(12) A°) and complex 2 (2.0239(9)–2.0489(9) Å) are typical, but the axial ligands are coordinated with a Cu Cl bond length of 2.5962 (7) Å for complex 1 , and the Cu N (azido) bond length is 2.1990 (10) Å for complex 2 , adopting square-planar geometry around the Cu(II) with four N atoms from two N -Metn or Me 2 tn ligands. The crystals are stabilized by a three-dimensional network of intermolecular hydrogen bonds that are formed between the primary and secondary amine groups of the N -Metn ligands, the Cl ligands, and the F atoms of BF 4 − anion in 1 , and by the primary amine groups of the Me 2 tn ligands and the N atoms of the azido ligand and azide ion in 2 . Hirshfeld surface analysis with 2D fingerprint plots revealed that the H⋯H, F⋯H, Cl⋯H contacts in 1 and the H⋯H and N⋯H contacts in 2 are the main intermolecular interactions. The electronic absorption and IR spectral properties are also discussed. [ABSTRACT FROM AUTHOR]

The new proligand 2-benzoylpyridine-3-methoxybenzhydrazone (HL) and its three copper(II) complexes have been synthesized and characterized by different physicochemical techniques, including molar conductivity measurements, magnetic studies, electronic, infrared and EPR spectral studies. The crystal structures of HL and its copper complexes have been resolved using single crystal X-ray studies. The reaction of 2-benzoylpyridine-3-methoxybenzhydrazone with a variety of copper salts yielded a series of copper(II) complexes of the type [CuLX] 2 where X = Cl ( 1 ), Br ( 2 ) and N 3 ( 3 ). The crystal structures of all these compounds revealed halogen/azide bridged box dimers having the monoclinic space group symmetry P 2 1 / n . All the complexes have a distorted square pyramidal geometry. [ABSTRACT FROM AUTHOR]

The complexes of N2O2-, N2O3- and N2O5-donors Schiff bases with CuII ions in the methanol solution have been synthesized. They were characterized by elemental analysis, X-ray crystallographic techniques, spectroscopic (UV–Vis, IR) and thermal (TG, TG-FTIR) methods. The catalytic activity of the prepared complexes for the hydrogen peroxide-assisted degradation of methylene blue (MB) as the model compound in water was also investigated. The complexes were obtained as crystalline solids. Depending on the Schiff bases and the molar ratio of CuII:ligand used in the synthesis, they can form monomeric or dimeric structures. The coordination environment around the metal centre in both solution and solid states is a slightly distorted square-planar. The values of magnetic moments determined at room temperature show the existence of antiferromagnetic interactions. The complexes are stable at ambient temperature. After heating, at first solvates lose solvent molecules; after that, an organic part undergoes gradual defragmentation and combustion. Degradation efficiency of MB in the presence of complexes was found to be 68.18–97.47%. A tentative mechanism involving HO· radical as an oxidant for degradation of MB was proposed. [ABSTRACT FROM AUTHOR]

A new series of twelve bidentate Schiff's base ligands (HL1–12) was synthesized via condensation of 5‐(arylazo)salicylaldehydes with aromatic amines. When the new salicylaldimine derivatives were reacted with copper(II) chloride, the neutral complexes Cu(L1–12)2 were obtained. The structure of the copper complexes was established from microanalyses, IR and UV spectra and thermal analyses. The results suggested that the ligands were coordinated to the metal ion in a bidentate manner with ON donor sites of the deprotonated phenolic‐OH and azomethine‐N. The composition of the complexes can be represented as CuL2. Evaluation of antimicrobial activity for the synthesized compounds was carried out to probe their activity. The compounds were found to have weak antimicrobial activity. [ABSTRACT FROM AUTHOR]

Two water‐soluble 6‐(pyrazin‐2‐yl)‐1,3,5‐triazine‐2,4‐diamino (pzta)‐based Cu(II) complexes, namely [Cu( l‐Val)(pzta)(H2O)]ClO4 (1) and [Cu( l‐Thr)(pzta)(H2O)]ClO4 (2) ( l‐Val: l‐valinate; l‐Thr: l‐threoninate), were synthesized and characterized using elemental analyses, molar conductance measurements, spectroscopic methods and single‐crystal X‐ray diffraction. The results indicated that the molecular structures of the complexes are five‐coordinated and show a distorted square‐pyramidal geometry, in which the central copper ions are coordinated to N,N atoms of pzta and N,O atoms of amino acids. The interactions of the complexes with DNA were investigated using electronic absorption, competitive fluorescence titration, circular dichroism and viscosity measurements. These studies confirmed that the complexes bind to DNA through a groove binding mode with certain affinities (Kb = 4.71 × 103 and 1.98 × 103 M−1 for 1 and 2, respectively). The human serum albumin (HSA) binding properties of the complexes were also evaluated using fluorescence and synchronous fluorescence spectroscopies, indicating that the complexes could quench the intrinsic fluorescence of HSA in a static quenching process. The relevant thermodynamic parameters revealed the involvement of van der Waals forces and hydrogen bonds in the formation of complex–HSA systems. Finally, molecular docking technology was also used to further verify the interactions of the complexes with DNA/HSA. [ABSTRACT FROM AUTHOR]

Mononuclear copper(II) complexes with 2,2′:6′,2″-terpyridine (terpy), [Cu(terpy)(ClO 4 ) 2 (H 2 O)] ( 1 ) and [Cu(terpy) 2 ](CF 3 SO 3 ) 2 ·2H 2 O ( 2 ), were synthesized and structurally characterized by UV–Vis and IR spectroscopy, ESI mass spectrometry and single-crystal X-ray diffraction analysis. In vitro study of cytotoxicity of the complexes demonstrated good antiproliferative properties in the case of human non-small cell lung cancer (A549), as well as in lung fibroblast (MRC5) cell line. Copper(II) complexes with terpy showed significant ability to interact with the high molecular weight double stranded DNA, without induction of DNA damage. On the other side, they caused nicking of plasmid DNA without presence of co-oxidant, indicating moderate nucleolytic activity. Circular dichroism spectra confirmed intercalation of the complexes to double-stranded DNA. Molecular docking studies also indicated strong binding affinity of the complexes with DNA revealing that two forms of 1 ( 1a and 1b with and without coordinated perchlorate ion, respectively) and 2 bind to the major groove of DNA. [ABSTRACT FROM AUTHOR]

The homochiral coordination polymers [Cu4(CH3OH)(H2O)4(Hbtb)(S-mal)2]•4H2O and [Cu4(CH3OH)(H2O)4(Hbtb)(R-mal)2]•4H2O were synthesized by heating S- or R-malic acid (H3mal), 4,4′,4″-benzene-1,3,5-triyltris(benzoic acid) (H3btb), and copper(II) acetate in an aqueous methanolic solution. The reaction with copper(II) nitrate in aqueous dioxane afforded the coordination framework [Cu6(C4H8O2)3(H2O)3(btb)4]•4C4H8O2•10H2O, which does not contain chiral ligands. The compositions and crystal structures of the new compounds were determined by single-crystal X-ray diffraction and confirmed by X-ray powder diffraction, IR spectroscopy, thermogravimetric and elemental analysis. [ABSTRACT FROM AUTHOR]

Two new copper(II) complexes containing the methyl(2-pyridyl)ketone oxime ligand (mpkoH) [Cu 3 (OH)(ClO 4 ) 2 (mpko) 3 ]·CH 3 OH ( 1 ) and [Cu(ClO 4 )(mpko)(mpkoH)] n ( 2 ) have been prepared from Cu(ClO 4 ) 2 and mpkoH in different metal-to-ligand molar ratios. In addition, the compound [Cu{(mpko) 2 BF 2 }(H 2 O)](BF 4 ) ( 3 ) [(mpko) 2 BF 2 is the fluoroboration product of the oxime] has been obtained when replacing Cu(ClO 4 ) 2 by Cu(BF 4 ) 2 . Compound 1 is an isolated triangle with a {Cu 3 (µ 3 -OH)} 5+ core, whereas 2 is a chain of Cu II ions linked by anionic mpko − bridges. 1 exhibits strong antiferromagnetic competing interactions, as well as antisymmetric exchange. On the other hand, very weak ferromagnetic interactions are found in 2 . The magnetic properties of these compounds have been analyzed by magnetic measurements and EPR spectra. [ABSTRACT FROM AUTHOR]

Reaction of picolinamide (pca) with potassium tricyanomethanide (tcm) and copper(II) perchlorate in 1-propanol gave [Cu(pca)2(tcm)2] (1aand1b) while addition of 2-(aminomethyl)pyridine (2-ampy) provided [Cu(pca)(2-ampy)(tcm)](ClO4) (2). These compounds have been characterized by IR, powder X-ray diffraction, single crystal X-ray diffraction, combustion analysis, and temperature-dependent magnetic susceptibility. Compound1acrystallized in the monoclinic space groupC2/cwhereas1band2crystallized in the triclinic space groupPī.In1a,the copper complexes stack alternately with semi-coordinated tcm ions creating layers, further stabilized by hydrogen bonding to neighboring layers. In1b,the tcm ions are coordinated to complete the octahedral coordination sphere around the copper ions and form staggered layers parallel to theabface diagonal. In2, stacks of copper complexes form bilayers, held together by hydrogen bonding between tcm ions and amino groups, parallel to theaaxis. Variable temperature magnetic susceptibility data were collected on1and2from 1.8–310 K. The data were fit to the Curie–Weiss law which showed no significant magnetic exchange as expected based upon the crystal structures [1 − Curie constant = 0.419(2) emu-K/mol-Oe,θ = −0.10(6)°;2– Curie constant = 0.438(1) emu-K/mol-Oe,θ = 0.05(3)°]. [ABSTRACT FROM PUBLISHER]

The kinetics and thermodynamics have been studied for the reactions of the copper(II) complexes with iminodiacetate (ida), 2,2′-bipyridine (bipy) and 1,10-phenanthroline (phen) as ligands. The kinetics of substitution reactions of two aqua ligands for bipy and phen in the [Cu(ida)(HO)] coordination compound has been studied in water and three type of aqueous solutions of the following surfactants: anionic sodium dodecyl sulfate (SDS), cationic hexadecyl trimethyl-ammonium bromide (CTAB) and nonionic t-octylphenoxypolyetoxyethanol (Triton X-100). The progress of the substitution reactions in the studied solutions was monitored spectrophotometrically using the stopped-flow method. The studies have allowed the determination of the effect of the type of surfactant solutions on the rate of the substitution reaction. Moreover, the order of studied reactions has been determined. The research performed has also allowed us to propose the reaction mechanism of the [Cu(ida)(HO)] binary complex with chelate ligands (bipy or phen). In addition, the thermodynamic stability of complexes under study in aqueous solutions has been examined using the potentiometric titration method. Moreover, the potential scavenging activity of the copper(II) complexes has been investigated towards the superoxide radical. [ABSTRACT FROM AUTHOR]

The reaction of Cu(CH 3 COO) 2 · H 2 O and Cu(ClO 4 ) 2 ·6H 2 O with bis(3,5-dimethylpyrazol-1-yl)methane ligand ( L ) yielded complexes [Cu(CH 3 COO) 2 ( L )] ( 1 ) and [Cu( L ) 2 (H 2 O)](ClO 4 ) 2 ( 2 ), which were isolated as air-stable solids. The complexes were characterized by electrical conductivity; thermogravimetric analysis; cyclic voltammetry; and Raman, infrared and ultraviolet/visible spectroscopy. The structure of 2 was determined by single-crystal X-ray diffraction analysis. Graphite electrodes modified with each of the complexes were used to detect dopamine using differential pulse voltammetry. In the presence of ascorbic acid and uric acid, the highest sensitivity (2.01 μA μM − 1 cm − 2 ) and the lowest detection limit (0.5 μM) were obtained with the electrode modified with 1 . The linearity of the signal, the sensitivity and the detection limit were significantly improved when the solution contained polystyrenesulfonate (PSS − ), demonstrating the synergistic effect between the complexes modifying the electrode surface and the PSS − in solution. [ABSTRACT FROM AUTHOR]

The redox mediator used in dye-sensitized solar cells present several disadvantages; several research groups have theorized the possible use of blue copper proteins as electron mediators, despite their high costs. Copper complexes that mimic blue copper proteins could represent an alternative as electronic transfer agent with lower costs. In this work, we conducted a spectrophotometric study of the speciation of copper(II) complexes with 2,2′-bipyridyl, 1,10-phenanthroline and their ternary complexes with chloride and bromide, at 303 K. For the copper–2,2′-bipyridyl complexes, the formation constants obtained are: log β 110 = 7.57 ± 0.08, log β 120 = 13.26 ± 0.11 and log β 130 = 17.21 ± 0.14. For the ternary systems of copper–2,2′-bipyridyl with chloride or bromide, are: log β 111 = 12.06 ± 0.06 and log β 111 = 11.23 ± 0.01, respectively. Also, the formation constants obtained for the copper–1,10-phenanthroline complexes are log β 110 = 4.21 ± 0.01 and log β 120 = 7.24 ± 0.02. For the ternary systems of copper(II) with 1,10-phenanthroline and chloride or bromide, are: log β 111 = 6.14 ± 0.04 and log β 111 = 7.46 ± 0.03, respectively. Finally, the individual calculated electronic spectra of these species were obtained and compared to other copper complexes mimicking to blue copper proteins. [ABSTRACT FROM AUTHOR]

A mixture of copper(II) chloride dihydrate and ligands derived from amantadine and 5-halogenated salicylaldehyde in anhydrous methanol generated two novel complexes CHClCuNO ( I) and CHBrCuNO ( II), respectively. The complexes were characterized by melting point, elemental analysis, molar conductance, IR, UV-Vis, and single-crystal X-ray diffraction (CIF files nos. 1435429 ( I), 1435430 ( II)). Single-crystal X-ray diffraction analysis reveals that both complexes crystallize in monoclinic system, P2/ c space group. Each asymmetric unit consists of two mononuclear copper(II) complex molecules and each complex molecule includes one copper(II) atom two corresponding deprotonated ligands. The central copper(II) atom is four-coordinated via two nitrogen atoms and two oxygen atoms from the corresponding Schiff base ligands, forming a distorted tetrahedral geometry. Electrochemical properties of the complexes were studied by cyclic voltammetry. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) calculations of the structures and the Cu2+ g factors (gx, gy and gz) and hyperfine coupling tensor A (Ax, Ay and Az) were performed for the paddle-wheel (PW)-type binuclear copper(II) complex {Cu2(μ2-O2CCH3)4}(OCNH2CH3) powder and single crystal. Calculations were carried out with the ORCA software using the functionals BHandHlyp, B3P86 and B3LYP with five different basis sets: 6-311g, 6-311g(d,p), VTZ, def-2 and def2-TZVP. Results were tested by the MPAD analysis to find the most suitable functional and basis sets. The electronic structure and covalency between copper and oxygen were investigated by the electron localisation function and the localised orbital locator as well as the Mayer bond order for the [CuO5] group. The optical spectra were theoretically calculated by the time-dependent DFT module and plotted by the Multiwfn program for the [CuO5] group and reasonably associated with the local structure in the vicinity of the central ion copper. In addition, the interactions between the OCNH2CH3, NH3 and H2O molecules and the uncoordinated PW copper(II) complex were studied, and the corresponding adsorption energies, the frequency shifts with respect to the free molecules and the changes of the Cu-Cu distances were calculated and compared with the relevant systems. [ABSTRACT FROM AUTHOR]

Transition metal ions such as iron, copper, zinc, manganese or, nickel are essential in many biological processes. Bacteria have developed a number of mechanisms for their acquisition and transport, in which numerous of proteins and smaller molecules are involved. One of the representatives of these proteins is FeoB, which belongs to the Feo (ferrous ion transporter) family. Although ferrous iron transport system is widespread among microorganisms, it is still poorly described in Gram-positive pathogens, such as Staphylococcus aureus. In this work, combined potentiometric and spectroscopic studies (UV–Vis, CD and EPR) were carried out to determine Cu(II), Fe(II) and Zn(II) binding modes to FeoB fragments (Ac-IDYHKLMK-NH 2 , Ac-ETSHDKY-NH 2 , and Ac-SFLHMVGS-NH 2). For the first time iron(II) complexes with peptides were characterized by potentiometry. All studied ligands are able to form a variety of thermodynamically stable complexes with transition metal ions. It was concluded that among the studied systems, the most effective metal ion binding is observed for the Ac-ETSHDKY-NH 2 peptide. Moreover, comparing preferences of all ligands towards different metal ions, copper(II) complexes are the most stable ones at physiological pH. Protonation equilibria and binding mode of Cu(II), Fe(II), and Zn(II) ions by FeoB transporter regions from Staphylococcus aureus were studied using potentiometry, UV–Vis, CD and EPR. Metal ion binding affects the secondary structure of the peptides. The most effective chelation is observed for the Ac-ETSHDKY-NH 2 peptide. [Display omitted] • Thermodynamic and spectroscopic studies of FeoB protein fragments from S. aureus. • Metal ion complexes with histidine-containing peptides. • Potentiometric studies of metal-peptide complexes containing Cu(II), Fe(II), and Zn(II). • Influence of the metal ion on the secondary structure of the peptide. [ABSTRACT FROM AUTHOR]

• A series of mixed-ligand Cu(II) complexes were synthesized and characterized. • The anti-lung cancer activity of these Cu complexes were evaluated in vitro. • We revealed the anticancer mechanism of the Cu(II) complex. • The ability of complex 4 to inhibit the growth of A549 tumor spheroids was assessed. [Display omitted] Here we synthesized five mixed-ligand copper(II) Schiff-base complexes, including [Cu(HL1)(pyridine) NO 3 ] 1 , [Cu(HL2)(pyridine)Cl] 2 , [Cu(HL3)(pyridine)Br] 3 , [Cu(HL4)(pyridine)Br] 4 , and [Cu(L5)(pyridine)] 5 , and performed a series of assays to investigate their anti-lung cancer activities in vitro. The structures of these copper(II) complexes were confirmed by X-ray crystallography and elemental analysis. MTT assay showed that complex 4 exhibited stronger cytotoxicity than other complexes. The wound healing assay showed that complex 4 had the well potential to display anti-metastatic activity. Flow cytometry and fluorescence imaging analysis showed that complex 4 led to cell cycle arrest at the S phase and induced mitochondria-mediated apoptotic. Furthermore, in the 3D A549 spherical model, complex 4 clearly exerts an inhibitory effect. [ABSTRACT FROM AUTHOR]

2-Acetylpyridine acetylhydrazone (H2AcMe), 2-benzoylpyridine acetylhydrazone (H2BzMe) and complexes [Cu(H2AcMe)Cl2] (1) and [Cu(H2BzMe)Cl2] (2) were assayed for their cytotoxicity against wild type p53 U87 and mutant p53 T98 glioma cells, and against MRC-5 fibroblast cells. Compounds 1 and 2 proved to be more active than the corresponding hydrazones against U87, but not against T98 cells. Compound 1 induced higher levels of ROS than H2AcMe in both glioma cell lines. H2AcMe and 1 induced lower levels of ROS in MRC5 than in U87 cells. Compound 2 induced lower levels of ROS in MRC5 than in T98 cells. The cytotoxic effect of 1 in U87 cells could be related to its ability to provoke the release of ROS, suggesting that the cytotoxicity of 1 might be somehow p53 dependent.

Six series of structurally different mono- and binuclear copper(II) complexes 5–10 were obtained by reacting N-(2-pyridyl)imidazolidin-2-ones (1a–l), N,N'-bis(2-pyridyl)imidazolidin-2-ones (2a,b), N-acyl-N'(2-pyridyl)imidazolodin-2-ones (3a–j) and N-(2-pyridyl)imidazolidine-2-thiones (4a–g) with copper(II) chloride at an ambient temperature. The coordination modes of the complexes obtained were established by elemental analysis, IR spectroscopic data and single crystal X-ray diffraction studies. The in vitro cytotoxic activities of both the free ligands and copper(II) complexes were evaluated using a crystal violet microtiter plate assay on five human tumor cell lines: LCLC-103H, A-427, SISO, RT-4 and DAN-G. The free ligands 1–4 at concentration attainable in cancer cells of 20 μM showed no meaningful cytotoxic effect with cell viability in the range of 88%–100%. The most potent copper(II) complex of 1-(6-ethoxy-2-pyridyl)imidazolidin-2-one (6b) exhibited selective cytotoxicity against A-427 lung cancer cell line, while the complexes of 1-(5-methyl-2-pyridyl)imidazolidine-2-thione (5h) and 1-(4-tert-butyl-2-pyridyl)imidazolidine-2-thione (5j) showed cytostatic effect against a whole panel of five human tumor cell lines. In conclusion, the only complexes that showed remarkably increased activity in comparison to the free ligands were those obtained from N-(2-pyridyl)imidazolidine-2-thiones 4c and 4e substituted with alkyl group at position 4 or 5 of pyridine ring.

The synthesis and structural characterization of a square-planar copper(II) complex with pyridoxal S-methylisothiosemicarbazone (PLITSC) of the formula [Cu(PLITSC−H)H2O]Br•H2O (1) as the first Cu(II) complex with monoanionic form of this ligand were described. Complex 1 together with two previously synthesized complexes [Cu(PLITSC)Br2] (2) and [Cu(PLITSC)Br(MeOH)]Br (3) were characterized by elemental analysis, IR and electronic spectra and also by the methods of thermal analysis, conductometry and magnetochemistry. [Projekat Pokrajisnkog sekretarijata za nauku i tehnoloski razvoj Vojvodine i Ministarstva nauke Republike Srbije, br. 172014]

Schiff bases are the most extensively used versatile ligands, capable of coordinating several chemical elements and stabilizing them in numerous oxidation states. [...]

Osadzenie kompleksu miedzi(II) z zasadą Schitta typu salen na zeolicie typu NaY zostało prze powadzone za pomocą dwóch metod „flexible ligand" i „in situ”. Katalityczne właściwości otrzymanego kompleksu oraz jego heterogenizowanych analogów badano w reakcji utleniania styrenu w obecności TBHP. Jako rozpuszczalnik stosowano acetonitryl. Testowane katalizatory wykazują średnią aktywność katalityczną z tendencją wytwarzania aldehy du benzoesowego. Oba heterogenizowane katalizatory mogą być wykorzystywane ponownie bez utraty aktywności katalitycznych.

Novel ether based Schiff bases (HL 1 - HL 4 ) were synthesized from 5-chloro-2-hydroxy benzaldehyde and primary amines (1-amino-4-phenoxybenzene, 4-(4-aminophenyloxy) biphenyl, 1-(4-aminophenoxy) naphthalene and 2-(4-aminophenoxy) naphthalene). From these Schiff bases copper(II) complexes (Cu(L 1 ) 2 -Cu(L 4 ) 2 )) were synthesized and characterized by elemental analysis and spectroscopic (FTIR, NMR) techniques. The synthesized Schiff bases and copper(II) complexes were further assessed for various biological studies. In brine shrimp assay the copper(II) complexes revealed 4-fold higher activity (LD 50 3.8 μg/ml) as compared with simple ligands (LD 50 12.4 μg/ml). Similar findings were observed in potato disc antitumor assay with higher activities for copper(II) complexes (IC 50 range 20.4–24.1 μg/ml) than ligands (IC 50 range 40.5–48.3 μg/ml). DPPH assay was performed to determine the antioxidant potential of the compounds. Significant antioxidant activity was shown by the copper(II) complexes whereas simple ligands have shown no activity. In DNA protection assay significant protection behavior was exhibited by simple ligand molecules while copper(II) complexes showed neutral behavior (neither protective nor damaging). [ABSTRACT FROM AUTHOR]

The synthesis of the complex {[Cu(BZIMU) 2 ](NO 3 ) 2 } ( 1 ) (BZIMU = 2-Benzimidazolyl-urea) is reported here. The complex 1 was characterized by elemental analysis, FT-IR, magnetic susceptibility and molar conductance measurements. The crystal structures of 1 and of the nitrate salt of [(BZIMUH + )(NO 3 ) - ] ( 2 ) were determined by X-ray diffraction analysis. The copper complex 1 and [(BZIMUH + )(NO 3 ) - ] ( 2 ) were evaluated for their in vitro cytotoxic activity (cell viability) against human cervix adenocarcinoma (HeLa) and human breast adenocarcinoma (MCF-7) cell line and normal human fetal lung fibroblast cells (MRC-5) with SRB assay. [ABSTRACT FROM AUTHOR]

Toxoplasma gondii is the causative agent of toxoplasmosis, which is one of the most common parasitic diseases in the world. This pathogen causes severe damage to immunocompromised hosts, and the most frequently used therapy is the combination of pyrimethamine and sulfadiazine, which has side effects. Thus, there is a need for new therapies that target T. gondii . Herein, we present the anti- Toxoplasma effect of two new copper(II) complexes: [(H 2 L1) Cu (μ-Cl) 2 Cu(H 2 L1)] Cl 2 ·5H 2 O (1) and [(H 2 L 2 ) Cu (μ-Cl) 2 Cu(H 2 L 2 )] Cl 2 ·6H 2 O (2). Complexes (1) and (2) irreversibly controlled parasite growth in vitro , with IC 50 values of 0.78 μM and 3.57 μM, respectively, after 48 h. These complexes induced part of the tachyzoite population to convert to bradyzoites, which eventually die. The cell death mechanism was unknown, but signs of apoptosis, such as membrane blebs and nuclear fragmentation, and necrosis, such as plasma membrane disruption, intense cytoplasm vesiculation and the release of cellular contents, were seen. In addition, complex (2) interfered with the correct disposition of the inner membrane complex of the parasite, affecting cell division. These results indicate that these copper complexes have potential effects against T. gondii and may be used as drugs in the future or serve as prototypes for the development of new drugs to treat toxoplasmosis. [ABSTRACT FROM AUTHOR]

Goserelin acetate (Gos) as a synthetic analog of the mammalian gonadotropin-releasing hormone (GnRH) is widely used in the treatment of sex hormone-related conditions. In this paper we present the chemical and biological aspects of its interaction with Cu(II) ions. The mode of Cu(II) binding and the thermodynamic stability of the obtained complexes were characterized by potentiometry, UV–Vis and CD spectroscopic methods. The DFT calculations were applied in order to investigate and confirm the molecular structure of the studied systems. The experimental and theoretical results clearly indicated the involvement of three nitrogens from the peptide and two oxygens from the acetate moieties in the Cu(II) coordination under physiological conditions. The investigated metallopeptide caused single- and/or double cleavage of the sugar-phosphate backbone of the plasmid DNA in the reaction accompanied by endogenous substances such as hydrogen peroxide or ascorbic acid. The degradation of the DNA molecule occurred via the free radical mechanism. Calculations based on measured spectra allowed determining the kinetic parameters of OH formation. The cytotoxic effects of Gos and its metallo-derivative were tested in vitro towards two cancer cell lines (A549 – human lung adenocarcinoma, CT26 – mouse colon carcinoma). [ABSTRACT FROM AUTHOR]

Neb -colloostatin was discovered during the isolation of Neb -TMOF from the ovary of the grey fleshfly Neobellieria bullata . Its amino acid sequence was determined as SIV P 4 LGL P 8 V P 10 IG P 13 IVVG P 18 R. The analogues with point mutation P4H and P8H were synthesized and their copper(II) complexes were studied by potentiometry, UV–Vis, circular dichroism (CD), and electron paramagnetic resonance (EPR) spectroscopic and mass spectrometry (MS) methods. To obtain a complete complex speciation 1:1 and 2:1 metal-to-ligand molar ratios for both peptides were studied. At physiological pH (7.4), both peptides form mononuclear the CuH -1 L complex with 3N{NH 2 , N − , N Im } coordination mode. For the P4H and P8H peptides at high pH (∼11) the binding sites of copper(II) ions are quite different. For the CuH -4 L complex of the P4H peptide the 4N{4N − } coordination mode is dominante, while for the P8H peptide the 4N{N Im , 3N − } binding site towards N-termini is formed with (6,5,5) chelate ring. At high pH the P8H peptide cannot form the 4N {NH 2 , 3N − } complex because of the presence of the Pro 4 residue in the amino acid sequence (a break point in the metal coordination). At pH 7.4 dinuclear the Cu 2 H -4 L complexes dominate with suggested the 3N{NH 2 , 2N − }3N{N Im , 2N − }binding sites where the 3N{N Im , 2N − } coordination mode for the P4H peptide towards C-termini, and for P8H peptide towards N-termini are formed. The induction of apoptosis in vivo in Tenebrio molitor cells by the ligands and their copper(II) complexes at pH 7.4 was studied. The systems studied have lower apoptotic properties compared to those of Neb -colloostatin and its copper(II) complex at pH 7.4. [ABSTRACT FROM AUTHOR]

[Cu(HL) 2 Cl 2 ] complexes ( 1 – 6 ) were prepared with trans -4-stilbenecarboxaldehyde- para -tolyl-hydrazone HSt p T ( HL1 ), trans -4-stilbenecarboxaldehyde- para -chloro-phenylhydrazone HSt p ClPh ( HL2 ), trans -4-stilbenecarboxaldehyde- para -hydroxy-phenylhydrazone HSt p OHPh ( HL3 ), trans -4-stilbenecarboxaldehyde- para -nitro-phenylhydrazone HSt p NO 2 Ph ( HL4 ), trans -4-stilbenecarboxaldehyde-acetylhydrazone HStAc ( HL5 ), and trans -4-stilbenecarboxaldehyde-benzoylhydrazone HStBz ( HL6 ). Infrared spectra suggested that the hydrazones act as bidentate ligands which bind to the copper(II) center through the N imine -O chelating system. EPR spectra of complexes ( 1 – 6 ) were recorded at room temperature for powder samples and at 77 K for DMSO solution. The EPR parameters were compatible with the presence of copper(II). Since the spectroscopic data for complexes ( 1 – 6 ) did not allow the unambiguous determination of the exact geometry of the complexes in the solid state or in solution, theoretical studies were carried out considering five possible isomers, in order to get information on the predominant species. However, although one of the isomers revealed to be the most thermodynamically favorable, free energy differences were not larger than 3 kcal·mol −1 . Hence, differences in lattice energy or packing forces could influence the geometry adopted in the solid. The thermodynamic analysis of the five isomers indicated that all of them are in equilibrium in solution. EPR studies suggested that complexes ( 1 – 6 ) interact with bovine (BSA) and human (HSA) serum albumin, with displacement of the hydrazone ligands and coordination of copper(II) to site 1, together with formation of hydrazone-cysteine mixed-ligand copper(II) complexes at site 2 of the albumins. [ABSTRACT FROM AUTHOR]

Amino alcohols which carry both amino and hydroxyl groups in the same molecule are good chelating and bridging ligands. They have been broadly used for the preparation of copper(II) amino alcoholate complexes through the self-assembly process, which generally leads to the formation of diverse structures from mononuclear to polynuclear copper(II) clusters. There are three main factors to control the nuclearity of these clusters: (i) the molar ratio of Cu(II) to amino alcohol, (ii) the choice of the counter anions and (iii) the nature of the amino alcohol. These structures can be used as model systems in magnetic studies, allowing a better understanding about the magnetic interactions between the metal centres, as well as simplified models of the active sites of many copper enzymes, which catalyse the hydroxylation of alkanes and other substrates. This review comprises the literature survey of copper(II) amino alcoholate complexes, presenting the structural diversity from mono- to nonanuclear clusters, from discrete molecules to coordination polymers or networks obtained using small bridging and chelating amino alcoholates with copper(II) ions. Several applications of these complexes have been presented. [ABSTRACT FROM AUTHOR]

A new series of six mononuclear copper(II) complexes were synthesized from N 3 O 2 and N 4 O 2 donors containing Schiff base ligands, and characterized by various spectral methods. The geometry of the complexes was determined using UV–Vis, EPR and DFT calculations. The complexes of N 3 O 2 donors ( 1 – 3 ) adopted square pyramidal geometry and the remaining complexes of N 4 O 2 donors ( 4 – 6 ) show distorted octahedral geometry around copper(II) nuclei. Redox properties of the complexes show a one-electron irreversible reduction process in the cathodic potential ( E p c ) region from −0.74 to −0.98 V. The complexes show potent antioxidant activity against DPPH radicals. Molecular docking studies of complexes showed σ–π interaction, hydrogen bonding, electrostatic and van der Waals interactions with VEGFR2 kinase receptor. In vitro cytotoxicity of the complexes was tested against human breast cancer (MDA-MB-231) cell lines and one normal human dermal fibroblasts (NHDF) cell line through MTT assay. The morphological assessment data obtained by Hoechst 33258 and AO/EB staining revealed that the complexes induce apoptosis pathway of cell death. [ABSTRACT FROM AUTHOR]

The 1D and the 2D copper(II) coordination polymers [{Cu(κ N , OO ′-L)} 2 ( μ -1κ N :2κ N′ -bpy) 2 ] n ( 1 ) and [{Cu( μ -1κ N , OO ′:2κ O ″-L)} 2 ( μ -1κ N :2κ N ′-hmt)] n ( 2 ), respectively, were synthesized from copper(II) nitrate and sodium 2-(2-(1,3-dioxo-1H-inden-2(3H)-ylidene) hydrazinyl)benzenesulfonate (NaHL), in the presence of 4,4′-bipyridine (4,4′-bpy) (for 1 ) or hexamethylenetetramine (hmt) (for 2 ). 1 and 2 are water soluble and are characterized by elemental analysis, IR spectroscopy, ESI-MS and single crystal X-ray diffraction. Depending on the neutral linkers, the dianionic ligand L 2− displays tri- (in 1 ) or tetradentate (in 2 ) binding modes. The Cu 2+ in 1 adopts a distorted N 3 O 2 square-pyramid coordination environment, while in 2 it displays a distorted N 2 O 3 trigonal bipyramid geometry. The catalytic activity of 1 and 2 was evaluated in the diastereoselective Henry reaction of nitroethane with a variety of aromatic and aliphatic aldehydes, in water and in organic solvents. β-Hydroxy nitroalkanes were obtained in high yields (up to 92%), and moderate-to-good syn/anti diastereoselectivities (up to 79:21), in water at room temperature. [ABSTRACT FROM AUTHOR]

Novel polydentate ligands on the basis of second- and third-generation hyperbranched polyesters containing terminal poly[3-(morpholin-4-yl)propionate] groups and their 6 : 1 and 13 : 1 polynuclear copper(II) complexes were synthesized. The degree of functionalization of the polyesters with morpholine increases in going from the second (56%) to third generation (68%). According to IR and electronic spectroscopy data, each coordination entity in the complexes is an isolated paramagnetic center of the formula CuNOSolv (Solv = HO, DMSO). [ABSTRACT FROM AUTHOR]

Tetranuclear copper(II) complex [CuL(OOC(CH)COO)] ( I) based on bis(azomethine), condensation product of 1-phenyl-3-methyl-4-formylpyrazolone-5 with 1,3-diaminopropanol-2, is synthesized. The structure of its DMSO-adduct ( Ia) is determined by X-ray diffraction analysis (CIF file CCDC 1447891). The complexes contain two binuclear fragments bonded by the µ-1,6-hexadicarboxylate linker. The magnetic exchange interaction in complex I is antiferromagnetic (2 J =-155 cm), whereas that in complex Ia is ferromagnetic (2 J = 129 cm), which is due to different conformations of the metallochelate cycles. [ABSTRACT FROM AUTHOR]

Two new copper(II)-amino acid complexes, [Cu(PyTA)( l -Thr)(ClO 4 )] 2 ·1.5H 2 O ( 1 ) and [Cu(PyTA)( l -Arg)(ClO 4 )(H 2 O)]·ClO 4 ( 2 ) (PyTA = 2,4-diamino-6-(2-pyridyl)-1,3,5-triazine, l -Thr = l -threonine, l -Arg = l -arginine), were successfully synthesized and characterized. The results determined by single crystal X-ray diffraction showed that the five-coordinated copper of 1 and the six-coordinated copper of 2 were located in the distorted square-pyramidal and distorted octahedral environments, respectively. Spectroscopic titrations, thermal denaturation experiments, viscosity measurements revealed that the complexes bound to DNA via a groove binding mode, with the DNA-binding constants of 6.126 × 10 4 M −1 for 1 and 6.464 × 10 4 M −1 for 2 . Electrophoresis experiments revealed that the complexes cleaved pBR322 DNA by an oxidative pathway involving in the generation of superoxide free radical (O 2 − ). Multi-spectroscopic analyses showed that the complexes bound to site I of human serum albumin (HSA) with moderate affinities. In particular, in vitro cytotoxicities of the complexes against Bel-7402 cell line showed promising anticancer effects (IC 50 = 42.1 ± 1.7 μM for 1 ; IC 50 = 36.3 ± 0.9 μM for 2 ). In addition, the binding mechanism and mode of the complexes with DNA/HSA were verified by molecular docking technique. [ABSTRACT FROM AUTHOR]