Copper Complexes

The formation of quadruple-stranded DNA induced by planar metal complexes has particular interest in the development of novel anticancer drugs. This is especially relevant for the inhibition of telomerase, which plays an essential role in cancer cell immortalization and is overexpressed in ca. 85-90% of cancer cells. Moreover, G-quadruplexes also exist in other locations in the human genome, namely oncogene promoter regions, and it has been hypothesized that they play a regulatory role in gene transcription. Herein we report a series of new anthracene-containing terpyridine ligands and the corresponding Cu(II) and Pt(II) complexes, with different linkers between the anthracenyl moiety and the terpyridine chelating unit. The interaction of these ligands and metal complexes with different topologies of DNA was studied by several biophysical techniques. The Pt(II) and Cu(II) complexes tested showed affinity for quadruplex-forming sequences with a good selectivity over duplex DNA. Importantly, the free ligands do not have significant affinity for any of the DNA sequences used, which shows that the presence of the metal is essential for high affinity (and selectivity). This effect is more evident in the case of the Pt(II) complexes. Moreover, the presence of a longer linker between the chelating terpyridine unit and the anthracene moiety enhances the interaction with G-quadruplex-forming sequences. We further evaluated the ability of the Cu(II) complexes to interact with, and stabilize G-quadruplex containing regions in oncogene promoters via a polymerase stop assay. These studies indicated that the metal complexes are able to induce G-quadruplex formation and stop polymerase activity.

A new dicationic ring [(water) 6 -(ammonium) 2 ] was found as a building block for a 3D supramolecular assembly of the compound ). The title compound was synthesized and characterized by single crystal X-ray diffraction at 100 K, infrared spectroscopy and thermogravimetric analysis. Compound 1 crystallizes in space group P-1 in the triclinic system with cell parameters: a = 11.1296( ) A ˚, b = 11.4790(4) A ˚, c = 11.8691(4) A ˚, a = 109.631(1)°, b = 100.601(1)°, c = 92.909(1)°and R(F 2 ) = 0.021. The threedimensional supramolecular structure is driven by intermolecular hydrogen bonds OÁÁÁH-N and OÁÁÁH-O from decavanadate anion with NH 4 ? and [(CH 3 ) 2- NC 5 H 4 NH] ? cations, as well as those formed between water molecules and decavanadate ions. The embedded rings consist of two sets of water-water-waterammonium chains joint together in a twisted chair conformation, in which water-ammonium pairs are at the top and bottom sites. The ring is hydrogen bond stabilized and represents to our knowledge, the first example of building block with this composition for a supramolecular structure to be reported.

Non-heme iron, vanadium, and copper complexes bearing hemicryptophane cavities were evaluated in the oxidation of methane in water by hydrogen peroxide. According to 1 H nuclear magnetic resonance studies, a hydrophobic hemicryptophane cage accommodates a methane molecule in the proximity of the oxidizing site, leading to an improvement in the efficiency and selectivity for CH 3 OH and CH 3 OOH compared to those of the analogous complexes devoid of a hemicryptophane cage. While copper complexes showed low catalytic efficiency, their vanadium and iron counterparts exhibited higher turnover numbers, ≤13.2 and ≤9.2, respectively, providing target primary oxidation products (CH 3 OH and CH 3 OOH) as well as over-oxidation products (HCHO and HCOOH). In the case of caged vanadium complexes, the confinement effect was found to improve either the selectivity for CH 3 OH and CH 3 OOH (≤15%) or the catalytic efficiency. The confined space of the hydrophobic pocket of iron-based supramolecular complexes plays a significant role in the improvement of both the selectivity (≤27% for CH 3 OH and CH 3 OOH) and the turnover number of methane oxidation. These results indicate that the supramolecular approach is a promising strategy for the development of efficient and selective bioinspired catalysts for the mild oxidation of methane to methanol.

Three novel Copper complexes, [Cu(L1)2][CuCl2] (1), [Cu(L2)Cl] (2) and [Cu2(L3)3Cl2] (3), have been prepared by reaction of CuCl with the Schiff-base ligands L1: N,N'-bis(thiophen-2-ylmethylene)-ethane-1,2-diamine, L2: N,N'-bis(1Hpyrrol-2-ylmethylene)ethane-1,2-diamine and L3: N,N'-bis(2-nitrobenzylidene)-ethane-1,2-diamine in acetonitrile. The solid-state structures of these complexes were determined by X-ray diffraction from single crystal data and characterized by 1H and 13C NMR, IR and UV/Vis spectroscopies. This study shows that (1) is an ionic complex with a Cu(I)-centered cation and an isolated linear dichlorocuprate(I) anion, (3) is a dinuclear neutral complex of Cu(I) while ( ) is a mononuclear neutral complex of Cu(II). In the three complexes, Cu is tetracordinated in different geometrical environments. The atomic arrangements and spectroscopic properties of the three complexes are reported. Complexes 1-3 exhibit, in the solid state at room temperature, photoluminescence between 320 and 550 nm.

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2-(2-(2-Hydroxyethylamino)ethylamino)cyclohexanol (HEAC) and copper and zinc complexes, [Cu(HEAC) Cl]Cl (1), [Cu(HEAC)Br]Br (2), [Zn(HEAC)Cl2] (3), were prepared and identified by elemental analysis, FT-IR, UV-Vis, H NMR spectroscopy and single-crystal X-ray diffraction. Also nanoparticles of 1–3 were prepared for anticancer studies by ultrasonic irradiation. Particle size and morphology of the nano particles are investigated by PXRD and SEM, respectively. X-ray analysis revealed that the ionic complexes 1 and 2 are isostructural. In the structure of complexes 1 and 2, the metal atom has a CuN2O2X (X: Cl (1), Br (2)) environment with square-pyramidal geometry, containing the tetradentate N2O2-donor HEAC. The bond length of the axial position in the square-pyramidal geometry of 1 and 2 is elongated. Complex 3 has a ZnN2OCl2 environment with trigonal bipyramidal geometry around the zinc atom in which the HEAC acts as mer-N2O-donor. The ability of HEAC and nano particles 1–3 to interac...

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Two new complexes [Cu(Cand)(H 2 O) 4 ] [1] and [Cu 2 (TCand) 4 (H 2 O) 2 ]•4H 2 O [2] (Cand = candesartan; TCand = trityl candesartan) have been synthesized and thoroughly characterized. The FTIR, Raman, EPR and diffuse reflectance spectra of the solid compounds show a dimeric complex for [2] with carboxylate bridging of the type found in copper(II) acetate. Both elemental analysis and thermal measurements allow the determination of the total stoichiometries of both complexes. The stability measurements show that the compounds are stable in ethanolic solutions at least for 1 h, while the preservation of the overall stochiometry for both species in solution has been determined by spectrophotometric titrations. By metal complexation the absence of antioxidant behavior of both sartans has been improved. Complexes [1] and [2] are strong superoxidedismutase mimetic compounds and complex [2] also behaves as a peroxyl radical scavenger. Furthermore, this higher antioxidant activity works in parallel with the improvement of the expansive activity over the angiotensin II-induced contracted human mesangial cells. These new complexes exhibit even higher efficiency as drugs in comparison with the free non-complexed medication with increased antioxidant ability expressing higher capacity to block the angiotensin II contractile effect. This study provides a new insight into the development of copper(II) complexes as potential drugs.

Synthesis and characterization: A wide range of differently substituted, achiral and chiral tetrahydrosalen or N,N´-dimethyl-tetrahydrosalen complexes with the metal ions copper(II), nickel(II), dioxomolybdenum(VI), oxovanadium (IV/V) and iron(III) are synthesized. The compounds were characterized by elemental analysis, melting point determination, IR, NMR and UV/Vis spectroscopy, mass spectrometry and by their magnetic moments. Crystal structures: X-ray structural analyzes were carried out of three different complexes of the N,N´-dimethyl-tetrahydrosalen type with the central atoms copper(II), dioxomolybdenum(VI) and oxovanadium(V). While in [Cu((tBu)(Me)[H 2 Me 2 ]salen)] (orthorhombic, P212121) the metal center is surrounded by the ligand framework in a squareplanar manner with a slight tetrahedral distortion, distorted octahedral coordination polyhedra result for the chiral complexes [MoO 2 ([H 2 Me 2 ] salchxn)]•CHCl 3 (monoclinic, P21) and [VO((tBu)(Me)[H 2 Me 2 ]salchxn)(OMe)] (monoclinic, P21). This shows the high flexibility of the tetrahydrosalen ligand framework, which can also adopt non-planar coordination geometries. The two cis-positioned oxo-O ligands in [MoO 2 ([H 2 Me 2 ]salchxn)]•CHCl 3 are in the trans position to the N-donor atoms. In [VO((tBu)(Me)[H 2 Me 2 ]salchxn)(OMe)], these positions are alternately occupied and disordered by a methoxide and an oxo-O ligand. The oxygen-vanadium bond of the methoxide ligand has significant π character....

The synthesis and characterisation of copper(I) complexes of chiral pyridine-containing macrocyclic ligands (Pc-L*) and their use as catalysts in asymmetric cyclopropanation reactions are reported. All ligands and metal complexes were fully characterised, including crystal structures of some species determined by X-ray diffraction on single crystals. This allowed characterising the very different conformations of the macrocycles which could be induced by different substituents or by metal complexation. The strategy adopted for the ligand synthesis is very flexible allowing several structural modifications. A small library of macrocyclic ligands possessing the same donor properties but with either C 1 or C 2 symmetry was synthesized. Cyclopropane products with both aromatic and aliphatic olefins were obtained in good yields and enantiomeric excesses up to 99%. Scheme 1 Synthesis of the macrocyclic ring system and numbering scheme adopted. † Electronic supplementary information (ESI) available: Synthetic and analytical data for all new compounds, spectra illustrating sample purity; crystallographic tables and CIF files for compounds 4d, 4f and 5d. CCDC 904090, 904091, 904092. For ESI and crystallographic data in CIF or other electronic format see

New thiosemicarbazone ligand derived from 4-formyl-3-hydroxy-2-naphthoic acid (H 3 L⋅CH 3 OH (1)) and their two copper(II) complexes with composition [Cu(H 2 L)Cl] 2. 2(dmf) (2), [Cu(H 2 L)NO 3 (dmf)] (3) were synthesized and characterized by thermal analysis, IR-, EPR-spectroscopy and single X-ray diffraction method. In both complexes the mono-deprotonated ligand coordinate tridentate to Cu(II) ion by ONS donor atoms provided by phenolic oxygen, azomethine nitrogen and thiol sulfur. In 2 binuclear complex has the square-planar environment of one copper(II) completed by Clanion, while a tetragonal pyramid of other metal is formed by Clanion and S atom from the neighboring organic ligand. The copper ion in the mononuclear complex 3 adopt a squarepyramidal structure, where the coordination number of copper(II) ion is adjusted to 5 by O atoms of NO 3 − anion and dimethylformamide molecule. Magnetic investigations of complex 2 revealed the presence of noticeable magnetic couplings between Cu(II) ions, while compound 3 shows the behavior typical of magnetically isolated Cu(II) centers. The compounds tested against St. aureus, C. albicans, E. coli and Kl. Pneumonia were found to be more active against gram-positive bacteria strains.

New thiosemicarbazone ligand derived from 4-formyl-3-hydroxy-2-naphthoic acid (H 3 L⋅CH 3 OH (1)) and their two copper(II) complexes with composition [Cu(H 2 L)Cl] 2. 2(dmf) (2), [Cu(H 2 L)NO 3 (dmf)] (3) were synthesized and characterized by thermal analysis, IR-, EPR-spectroscopy and single X-ray diffraction method. In both complexes the mono-deprotonated ligand coordinate tridentate to Cu(II) ion by ONS donor atoms provided by phenolic oxygen, azomethine nitrogen and thiol sulfur. In 2 binuclear complex has the square-planar environment of one copper(II) completed by Clanion, while a tetragonal pyramid of other metal is formed by Clanion and S atom from the neighboring organic ligand. The copper ion in the mononuclear complex 3 adopt a squarepyramidal structure, where the coordination number of copper(II) ion is adjusted to 5 by O atoms of NO 3 − anion and dimethylformamide molecule. Magnetic investigations of complex 2 revealed the presence of noticeable magnetic couplings between Cu(II) ions, while compound 3 shows the behavior typical of magnetically isolated Cu(II) centers. The compounds tested against St. aureus, C. albicans, E. coli and Kl. Pneumonia were found to be more active against gram-positive bacteria strains.

Copper conjugates of Schiff base derivatizves of nimesulide (1), a well-known cyclooxygenase-2 (COX-2) inhibitor, were synthesized, structurally characterized and evaluated for their COX selectivity indices and cytotoxicities on pancreatic tumor, BxPC-3 (COX-2 positive) and MiaPaCa (COX-2 negative) cell lines. Copper conjugates exhibit distorted square planar geometries as revealed by the single crystal X-ray structure determination of Cu(L1) 2 and show significant growth inhibition in both cell lines (IC50 values 3-26 lM for COX-2 positive and 5-9 lM for COX-2 negative cell line) than the parent nimesulide (35 lM for COX-2 positive and >100 lM for COX-2 negative cell line). The mechanistic pathway for the biological activity involves inhibition of vascular endothelial growth factor (VEGF) and COX inhibition, as well as down regulation of antiapoptotic Bcl-2 and Bcl-XL proteins.

Platinum metal complexes are the most common chemotherapeutics currently used in cancer treatment. However, the frequent adverse effects, as well as acquired resistance by tumor cells, urge the development of effective alternatives. In the recent past, copper complexes with Schiff base ligands have emerged as good alternatives, showing interesting results. Accordingly, and in continuation of previous studies in this area, three new camphoric acid‐derived halogenated salen ligands and their corresponding Cu (II) complexes were synthesized and their antitumor activity was evaluated in order to determine the influence of the type and number of halogens present (Br, Cl). The in vitro cytotoxic activity was screened against colorectal WiDr and LS1034 and against breast MCF‐7 and HCC1806 cancer cell lines. The results proved the halogenated complexes to be very efficient, the tetrachlorinated Cu (II) complex being the most promising, presenting IC50 of 0.63–1.09 μM for the cell lines stud...

The coordination chemistry of the tetrapodal-pentadentate ligand L, which has a mixed N 3 O 2 donor set, has been studied in the presence of copper(I) sources. The metal-to-ligand stoichiometry of the mononuclear copper(I) complexes resulting from 1:1 metal/ligand mixtures is markedly dependent on the character of the counter ion, giving 1:1 ([Cu(L)Cl]) and 1:2 complexes ([Cu(L) 2 ](PF 6)), with coordinating chloride and non-coordinating hexafluorophosphate, respectively. 1 H NMR and UV-Vis spectroscopy and single crystal X-ray structure analysis reveal tetrahedral coordination in both cases, with the "soft" copper centre engaging only two pyridine donors out of the N 3 O 2 donor set. Upon chemical oxidation of [Cu(L) 2 ](PF 6) with dioxygen or 3,5-di-tert-butyl-quinone, the same binuclear copper(II) complex [Cu 2 (LH) 2 ](PF 6) 2 is selectively formed, indicating metal-oxidation induced deprotonation of one ligand, extrusion of the second ligand and subsequent fusion of the coordination spheres via alkoxide bridges. Elongation along a Jahn-Teller active molecular axis in [Cu 2 (LH) 2 ] 2+ is affected by the nature of the counter ion, giving N 2 O 3 and N 3 O 2 coordination patterns in the hexafluorophosphate and in the chloride salt, respectively. In addition to the oxidised complex, isolated in close-to-quantitative yield, catechol is identified as the only reduction product, indicating a 2e  /2H + reduction of the quinone. Electron transfer from copper(I) to the chemical oxidant is suggested to steer the formation of base equivalents from O 2 and Q, which then drive ligand deprotonation and complex nucleation.

Various heterocyclic ligands [1,3-diarylpyrazole-4-carbaldehyde benzoyl-hydrazones] and their metal complexes with Cu 2+ , Ni 2+ , Co 2+ , Pb 2+ , Zn 2+ and Fe 2+ have been synthesized, characterized and screened for their antibacterial and antioxidant activities. The synthesized compounds were characterized through elemental analysis and spectroscopic techniques (FTIR, 1 H NMR and Mass).

Platinum metal complexes are the most common chemotherapeutics currently used in cancer treatment. However, the frequent adverse effects, as well as acquired resistance by tumor cells, urge the development of effective alternatives. In the recent past, copper complexes with Schiff base ligands have emerged as good alternatives, showing interesting results. Accordingly, and in continuation of previous studies in this area, three new camphoric acid‐derived halogenated salen ligands and their corresponding Cu (II) complexes were synthesized and their antitumor activity was evaluated in order to determine the influence of the type and number of halogens present (Br, Cl). The in vitro cytotoxic activity was screened against colorectal WiDr and LS1034 and against breast MCF‐7 and HCC1806 cancer cell lines. The results proved the halogenated complexes to be very efficient, the tetrachlorinated Cu (II) complex being the most promising, presenting IC50 of 0.63–1.09 μM for the cell lines stud...

Copper-based antitumor drug entities 1-3 derived from substituted (F-, Br- ,-CH 3) 3formylchromone pharmacophore were synthesized and thoroughly characterized by spectroscopic and single X-ray crystallographic studies. These complexes show structural novelty due to presence of the X-bonds in chromone scaffold which could facilitate higher propensity for nucleic acids via sigma σ-hole interactions. Therefore, structure-activity relationship of 1-3 was studied by performing ct-DNA binding, pBR322 cleavage and cytotoxicity activity to validate their potential to act as chemotherapeutic drug entities. The binding studies of 1-3 with ct-DNA were carried out employing many biophysical techniques and the corroborative results of these experiments showed intercalation mode of binding and the order of binding was found to be 2 > 1 >3. The structure of drug entities could facilitated strong halogen bonding interaction(in case of 1 &2) and stability of X bond was rationalized by sigma hole region of positive electrostatic potential on the surface of C-X covalent bond, as determined by gas phase B3LYP computational DFT studies. Interestingly, 2 exhibited most avid binding affinity due to presence of Brelectron withdrawing and polarizable group. Further, cleavage studies of 1-3 with pBR322 plasmid DNA were performed which demonstrated significant cleavage activity , the supercoiled form (Form I) of plasmid DNA was converted to nicked form (Form II) with the appearance of linearized form(Form III) in between two, implicating lethal double strand breaks of DNA. 2 showed predominantly higher cleavage activity following the similar trend as observed for binding studies. The cytotoxicity of the complexes 1-3 was evaluated by MTT assay against the human liver carcinoma (Huh-7) and prostate cancer (DU-145) cell lines; complex 2 exhibited specific and selective cytotoxicity for the DU-145 cancer cell line with LC 50 value of 1.6μM. Highlights  Substituted chromone Copper (II) complexes were synthesized and characterized.  DFT computational studies were also performed.  Electrophoretic studies revealed an oxidative cleavage pathway.  Cytotoxicity was evaluated against the human liver carcinoma (Huh-7) and prostate cancer (DU-145) cell lines.  Copper (II) complex 2 exhibited selective cytotoxicity against DU-145 cell line at GI 50 =1.6μM.

In this work, we explored the ability of N-methylS methyl dithiocarbazate ([H2N-N(CH3)C(=S)SCH3]; DTCZ) to form coordination complexes with copper starting from different copper (II, I) sources. Data proved that the type of used salt affects the stoichiometry and structure of the obtained coordination complexes. Copper complexes of general empirical formula [Cu(DTCZ)Cl2] (1), [Cu(DTCZ)2NO3]NO3 (2), [Cu(DTCZ)2(OH2)]SO4 (3), [Cu(DTCZ)2]PF6 (4), [Cu(DTCZ)(PPh3)2]NO3 (5) and [Cu(DTCZ)2]Br (6) were synthesized in high yield and characterized by elemental analysis, UV-Vis and IR spectroscopy. Molecular structures of 1-6 and also of sideproducts [Cu(DTCZ)2SO4] (3a), [Cu(DTCZ)2](PF6)(OH) (4b) and [CuBr(C3H7NS2)]n (6a) were determined by single crystal X-ray diffraction (XRD). In all cases, DTCZ binds the metal in the neutral form through the hydrazine nitrogen (NH2) and thione sulphur (S) atom set, forming monosubstituted and disubstituted complexes having tetrahedral, square planar, or square pyramidal geometries, depending on the copper source. In addition, two one-dimensional (1D) coordination polymers and water channels have been observed in the crystal states.

Binding of copper by reduced glutathione (GSH) is generally seen as a mechanism to lower, if not abolish, the otherwise high electrophilicity and redox activity of its free ions. In recent years, however, this concept has been contradicted by new evidence revealing that, rather than stabilizing free copper ions, its binding to GSH leads to the formation of a Cu(I)-[GSH] 2 complex capable of reducing molecular oxygen into superoxide. It is now understood that, under conditions leading to the removal of such radicals, the Cu(I)-[GSH] 2 complex is readily oxidized into Cu(II)-GSSG. Interestingly, in the presence of a GSH excess, the latter complex is able to regenerate the superoxide-generating capacity of the complex it originated from, opening the possibility that a GSH-dependent interplay exists between the reduced and the oxidized glutathione forms of these copper-complexes. Furthermore, recent evidence obtained from experiments conducted in non-cellular systems and intact mitochondria indicates that the Cu(II)-GSSG complex is also able to function in a catalytic manner as an efficient superoxide dismutating-and catalase-like molecule. Here we review and discuss the most relevant chemical and biological evidence on the formation of the Cu(I)-[GSH] 2 and Cu(II)-GSSG complexes and on the potential redox implications associated with their intracellular occurrence.

The title compound, Ag 11.60 H 0.40 [Cr(C 2 O 4) 3 ] 4 AE 15H 2 O (1) precipitates from aqueous solution as a dark violet solid in which silver ions are partially replaced by protons, and it crystallizes in an unusual structure with water-filled one-dimensional pseudo-nanotubes.

A series of 1,3,4-oxadizole derivatives containing 1,4-benzodioxane ring system were synthesized starting from 2,3-dihydro-1,4-benzodioxane-2-carbohydrazide. The synthesized compounds were characterized and evaluated for antibacterial activity against Staphylococcus aureus, Escherichia coli and Bacillus subtilis and antifungal activity against Aspergillus niger, Aspergillus flavus and Candida albicans by twofold serial dilution technique. Some of the synthesized compounds displayed comparable or even better antibacterial and antifungal activities than reference drugs norfloxacin, chloramphenicol and fluconazole, against tested strains.

Two tetranuclear Schiff base copper(II) complexes, namely[Cu 4 (L) 2 (LH) 2 (H 2 O) 2 ](ClO 4) 2 •3H 2 O (1) and [Cu 4 (L) 2 (LH) 2 (H 2 O) 2 ](ClO 4)•(tp) 0.5 •3H 2 O (2) (where H 2 L = 2-[(2-hydroxy-ethylimino)methyl]-6-methoxy-phenol, tp = terephthalate), were synthesized and characterized by X-ray single crystal diffraction. Both complexes 1 and 2 are comprised of structurally similar tetranuclear cationic [Cu 4 (L) 2 (LH) 2 (H 2 O) 2 ] 2+ species with a double open cubane core, in which the two metal centers possess a square pyramidal environment and the other two exhibit a slightly distorted octahedral coordination geometry. The interaction of complexes 1 and 2 with calf thymus DNA (CT-DNA) was investigated using electronic absorption and fluorescence studies, and the results showed that the complexes interact with CT-DNA with the related intrinsic binding constants (K ib) of 1.8×10 6 and 1.1×10 7 L mol-1 for 1 and 2, respectively. Their interactions with bovine serum albumin (BSA) and human serum albumin (HSA) were also investigated and spectroscopic techniques showed that both complexes interact with these proteins through a ground state association process. Using 3,5-di-tertbutylcatechol(3,5-DTBC) as a model substrate, both complexes show catecholase-like activity, being able to oxidase 3,5-DTBC to 3,5-di-tert-butylquinone (3,5-DTBQ) in the presence of oxygen.

Here, we report the performance of Co(II) and Cu(II) coordination complexes on H 2 O 2 activation. The heterogeneous catalysts containing aliphatic amine, N-heterocycle and/or carboxylic acid ligands in hydrogel materials coordinated with Co(II) or Cu(II) were used in this study. These complexes were characterized by solid-state NMR, X-ray photoelectron spectroscopy (XPS) and X-ray fluorescence techniques in order to quantify the superficial and bulk metal ion centers together with the aim to elucidate the ligands involved in the uptake of Co and Cu ions.

Here, we report the performance of Co(II) and Cu(II) coordination complexes on H 2 O 2 activation. The heterogeneous catalysts containing aliphatic amine, N-heterocycle and/or carboxylic acid ligands in hydrogel materials coordinated with Co(II) or Cu(II) were used in this study. These complexes were characterized by solid-state NMR, X-ray photoelectron spectroscopy (XPS) and X-ray fluorescence techniques in order to quantify the superficial and bulk metal ion centers together with the aim to elucidate the ligands involved in the uptake of Co and Cu ions.

In view of green route simplicity, cost effectiveness and eco-benign approach, this study focusses on the fabrication and characterization of copper nanoparticles (Cu NPs) using leaf extract (aqueous) of Parthenium hysterophorus (Gajar Booti). Characterization of P. hysterophorus mediated Cu NPs was performed by UV-Visible, Fourier-transform infrared, X-ray powder diffraction and scanning electron microscopy techniques. The UV-Vis characteristic peak was observed at 563 nm along with change in variation in color from light brown to dark green confirm the formation of Cu NPs. The Cu NPs was semi-spherical with average particle size of 15.48 nm. These green mediated Cu NPs was analyzed for their antibacterial activity by disc diffusion and MIC analysis and antibacterial activity was promising against Escherichia coli, Pasteurella multocida, Staphylococcus aureus and Bacillus subtilis strains. The Cu NPs also showed excellent antioxidant activity evaluated by DPPH free radical scavenging. In view of promising bioactivity, the Cu NPs prepared using P. hysterophorus extract could be used for biomedical applications.

A copper(II)-cofactor coupled to a testosterone anchor (10) was synthesized and associated with a neocarzinostatin variant, NCS-3.24 (KD = 3 µM), to generate a new artificial metalloenzyme following the so-called 'Trojan Horse' strategy. Interestingly, the artificial enzyme was able to efficiently catalyze the Diels-Alder cyclization reaction of cyclopentadiene (1) with 2 azachalcone (2). By Comparison with what was observed with cofactor (10) as the only catalyst, the artificial enzymes favored the formation of the exo-products with an endo/exo ration of 84/16 and 62/38, respectively after 12 h of reaction. Molecular modeling studies could assign the synergy between the copper complex and the testosterone (KD = 13 µM) moieties in the binding of cofactor (10) to a good van der Waals complementarity. Moreover, by pushing the modeling exercise to its limits we hypothesize on the molecular grounds that could be responsible for the observed selectivity.

The compound, tris-(5-methylbenzimidazole) tris-(oxalato)-aluminate (III) trihydrate, (C 8 H 9 N 2) 3 [Al(C 2 O 4) 3 ]•3H 2 O, was synthesized by slow evaporation at room temperature and characterized by single crystal X-ray diffraction and X-ray powder diffraction, infrared (IR), ultraviolet (UV-visible) spectroscopies, and thermal analysis. The results show that this complex crystallizes in the monoclinic system, space group P2 1 /c, with the mesh parameters a = 13.499(7) Å, b = 14.872(9) Å, c = 16.995(5) Å, ß = 91.44(3)˚, V = 3411(3) Å 3 and Z = 4. The formula unit is composed of tris-(oxalato)-aluminate [Al(C 2 O 4) 3 ] 3− anions, tris-(5-methylbenzimidazole) cations and three uncoordinated water molecules. The geometry of the aluminum ion is octahedral, formed by six oxygen atoms belonging to three oxalate anions serving as chelating ligands. Cohesion of the structure is ensured by intermolecular hydrogen bonds of O-H...O, N-H...O type linking ionic entities and water molecules as well as by π-π and π-π* between cycles of 5-methylbenzimidazole cations. In order to clarify the intermolecular interactions formed by the organic cations and inorganic anions, an analysis of the calculated Hirshfeld surfaces was used. The UV-Vis spectrum reveals an optical band gap width of 2.88 eV, which shows that this compound has a semiconductor material behavior.

Background:Ellagitannins have attracted much attention because of the biological and pharmacological activities. In the total synthesis of ellagitannins, 3,4,5-tri-O-benzylgallic acid has been a key compound to introduce the protected galloyl group. From the perspective of coordination chemistry, 3,4,5-tri-O-benzylgallic acid is an interesting carboxylate ligand which might be capable of dinuclear carboxylate complex. Such a dinuclear carboxylate complex might be interesting as a new example of copper acetate type complexes.Objectives:The objective of the work is to synthesize a copper acetate type complex by using 3,4,5-tri-O-benzylgallic acid and to see a new feature of copper acetate compounds, by elucidating the crystal structure, magnetic property, and adsorption property for N2gas.Methods:Copper(II) 3,4,5-tri-O-benzylgallate has been synthesized by a reaction of 3,4,5-tri-O-benzylgallic acid and copper(II) nitrate at pH=9 condition. The isolated complex was characterized using...

Dinuclear coordination compound of Cu(II), namely, [Cu 2 (pydc) 2 (pz)(H 2 O) 2 ]•2H 2 O, where pydc = pyridine-2,6-dicarboxylic acid (dipicolinic acid) and pz = pyrazine has been synthesized and characterized by elemental analysis, spectra (IR, UV-Vis), thermal (TG/DTG) analysis, magnetic measurements and single crystal X-ray diffraction. In the dimeric structure, the planar tridentate pyridine-2,6-dicarboxylic acid dianion coordinates to a Cu(II) ion in a meridional fashion and defines the basal plane of the complex. The fourth equatorial coordination site is then occupied by a pyrazine molecule that functions as a linear bidentate ligand bridging two Cu(II) complexes to form a dimer. The axial positions of each Cu(II) complex are occupied by one water molecule to form a distorted square pyramidal geometry. The complicated hydrogen bonding network accompanied with C-O•••π and C-H•••π stacking interactions assemble the crystal structure of 1 into a fascinating supramolecular architecture. Electrochemical behavior of [Cu 2 (pydc) 2 (pz)(H 2 O) 2 ] (Cu-PDAP) on the surface of carbon nanotube (CNTs) glassy carbon electrode (GCE) is described. Oxidation of cysteine on the surface of modified electrode was investigated with cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The results show that the Cu-PDAP/CNTs film displays excellent electrochemical catalytic activities towards L-cysteine oxidation.

The genetic algorithm, based on the Multi-Niche Crowding (MNC) method, coupled with the semi-empirical AM1 method is used to analyze the potential energy surface of some polypeptides containing cysteine. Calculating the formation energies of these systems in both neutral and deprotonated states, we deducted their enthalpy of deprotonation (ΔHacid) and we identified the types of rearrangement of these systems when isolated. Deprotonation occurs at the level of the alone acid site characterizing these peptides namely the thiol. The values obtained for the deprotonation enthalpies of polypeptides AlaCysNH2, Ala2CysNH2, Ala3CysNH2, Ala4CysNH2, CysAlaNH2 and CysAla2NH2 are in the order of 331.3 kcal/mol, 322.9 kcal/mol, 313.8 kcal/mol, 312.9 kcal/mol, 325.1 kcal/mol and 317.3 kcal/mol, respectively. The location of global and local minima of these polypeptides shows that they are rearranged in two forms of secondary structures namely helical and globular forms. The obtained results are in good agreement with the experimental ones, on the one hand, and with those from other methods in the theoretical calculation, on the other hand. Therefore, the N-cysteine is more acidic than their homologous C-Cysteine and for this series of plolyalanines, the acidity in the gas phase increased with the peptide chain length.

indole-1-acetic acid] is a nonsteroidal antiinflammatory drug that contains carboxylic acid group with the structure of pyrano[3,4-b]indole. In this study, a series of novel (R,S)-Etodolac derivatives (3a-l) bearing hydrazide-hydrazone moiety were synthesized. The structures of these compounds were characterized by spectral (1 H-NMR and FT-IR analyses) methods. All synthesized compounds were screened for anticancer activity against androgen-independent prostate adenocarcinoma (PC-3, DU-145) and androgen-dependent prostate adenocarcinoma (LNCaP) cell lines by using WST-8 colorimetric method. This method was used for cell viability and cytotoxicity analysis. Compound 3b (SGK-720) [2-(1,8-diethyl-1,3,4,9tetrahydropyrano[3,4-b]indole-1-yl)acetic acid[(2,6-dichlorophenyl)methylene]hydrazides] showed 10.36, 5.24, 15.53 µM anticancer activity against PC3, DU145, LNCaP cancer cell lines, respectively. According to JC-1 mitochondrial membrane potential test and Annexin V/PI staining, 3b was found to have apoptotic effect on these cancer cells. It is concluded that compound 3b containing 2,6-dichloro substituents may be one of the candidate molecules to cope with prostate cancer.

The Cr-doped aluminum oxalato complexes were obtained by substituting Al with trace of Cr. Three types of products were obtained in two colors: blue (one) and red (two). One of the red crystallizes in the hexagonal crystal system with space group R 3. The two red complexes possess the color-change property under different light sources (fluorescence and incandescence lights) similar to alexandrite-the rare and expensive gemstone.

The title compound, Ag 11.60 H 0.40 [Cr(C 2 O 4) 3 ] 4 AE 15H 2 O (1) precipitates from aqueous solution as a dark violet solid in which silver ions are partially replaced by protons, and it crystallizes in an unusual structure with water-filled one-dimensional pseudo-nanotubes.

Copper(II) bis-complexes with N-phosphoryl thioureas, RN 0 HCðSÞNPðOÞðOPr i Þ À 2 {R = phenyl (I), cyclohexyl (II)}, have been obtained and investigated in liquid and frozen toluene solutions. Equilibria between trans-S,N and cis-S,N-isomers have been revealed and described by EPR method. In contrast to more usual S,O-forms, trans-S,N-isomers demonstrate large superhyperfine splitting from N and P atoms simultaneously. From EPR spectra anisotropic hyperfine, superhyperfine, and g-tensor parameters obtained and the symmetry of the metal ion surrounding analyzed. Rhombic anisotropy of copper(II) hyperfine and axial symmetry of N and P superhyperfine splitting resolved. Structural, hydrodynamic, and magnetic characteristics of the complexes established experimentally were supported by DFT calculations. According to EPR and DFT studies, tetrahedral distortion is higher in cis-S,N than in trans-S,N forms for steric reasons and slightly higher in I(S,N-trans) isomer than in II(S,N-trans) one due to the electrondonating effect of cyclohexyl substituent. The domination of S,N-over S,O-coordination is explained by the effects of the crystal field stabilization and the formation of the intramolecular hydrogen bonds.

Binding of copper by reduced glutathione (GSH) is generally seen as a mechanism to lower, if not abolish, the otherwise high electrophilicity and redox activity of its free ions. In recent years, however, this concept has been contradicted by new evidence revealing that, rather than stabilizing free copper ions, its binding to GSH leads to the formation of a Cu(I)-[GSH] 2 complex capable of reducing molecular oxygen into superoxide. It is now understood that, under conditions leading to the removal of such radicals, the Cu(I)-[GSH] 2 complex is readily oxidized into Cu(II)-GSSG. Interestingly, in the presence of a GSH excess, the latter complex is able to regenerate the superoxide-generating capacity of the complex it originated from, opening the possibility that a GSH-dependent interplay exists between the reduced and the oxidized glutathione forms of these copper-complexes. Furthermore, recent evidence obtained from experiments conducted in non-cellular systems and intact mitochondria indicates that the Cu(II)-GSSG complex is also able to function in a catalytic manner as an efficient superoxide dismutating-and catalase-like molecule. Here we review and discuss the most relevant chemical and biological evidence on the formation of the Cu(I)-[GSH] 2 and Cu(II)-GSSG complexes and on the potential redox implications associated with their intracellular occurrence.

In this study, novel cupric-tirapazamine [Cu(TPZ)2]-liposomes were developed as an effective hypoxia-targeted therapeutic, which potentiated radiotherapy in a three dimensional (3D) prostate cancer (PCa) model. To overcome the low water solubility of the Cu(TPZ)2, a remote loading method was developed to efficiently load the lipophilic complex into different liposomal formulations. The effect of pH, temperature, PEGylation, lipid composition, liposome size, lipid: complex ratio on the liposome properties, and drug loading was evaluated. The highest loading efficiency was obtained at neutral pH, which was independent of lipid composition and incubation time. In addition, enhanced drug loading was achieved upon decreasing the lipid:complex molar ratio with minimal effects on liposomes' morphology. Interestingly, the in vitro potency of the developed liposomes was easily manipulated by changing the lipid composition. The hydrophilic nature of our liposomal formulations improved the complex's solubility, leading to enhanced cellular uptake and toxicity, both in PCa monolayers and tumour spheroids. Moreover, Cu(TPZ)2-loaded liposomes combined with radiation, showed a significant reduction in PCa spheroids growth rate, compared to the free complex or radiation alone, which could potentiate radiotherapy in patients with localised advanced PCa.

The aim of this study is to investigate the growth, structure, spectral, solubility and biological activity of sodium cadmium oxalate dehydrate (NaCdOx) and cadmium oxalate trihydrate (CdOx) crystals prepared by a single diffusion method in the silica gel medium. Methods: The present crystals were grown using single diffusion methods and tested for XRD, UV absorption (190 to 1100 mm) and solubility (distilled water at 20-29 °C) studies. The antimicrobial efficacy of the grown samples at various concentrations (25, 50, 75 and 100 μg/ml) was studied against Streptococcus, (G+Ve), Pseudomonas aeruginosa (G-Ve) and Candida albicans (antifungal). The cytotoxicity evolution was carried out against human cervical cancer cell line (HeLa) using MTT assays. Results: The existing single crystals were successfully grown by silica gel technique. The solubility of sodium cadmium oxalate dehydrate (NaCdOx) was moderately good in deionized warm water. The FTIR spectral studies confirmed the chelating bands of the present samples and UV spectra showed the better the optical conductivity of as-grown crystals. The complexes showed good antimicrobial activity against all tested microbial strains and they exhibited a decrease in cytotoxicity activity. Conclusion: The gel method was suitable to grow metal complexes of legend crystals. The modification of structural properties of cadmium oxalate trihydrate (CdOx) by sodium doping was much improved the solubility, anticancer, antimicrobial activity and polarization by the high optical conductivity of sodium cadmium oxalate dehydrate (NaCdOx) compound. Hence sodium cadmium oxalate dehydrate (NaCdOx) might be a candidate for biomedical applications.

indole-1-acetic acid] is a nonsteroidal antiinflammatory drug that contains carboxylic acid group with the structure of pyrano[3,4-b]indole. In this study, a series of novel (R,S)-Etodolac derivatives (3a-l) bearing hydrazide-hydrazone moiety were synthesized. The structures of these compounds were characterized by spectral (1 H-NMR and FT-IR analyses) methods. All synthesized compounds were screened for anticancer activity against androgen-independent prostate adenocarcinoma (PC-3, DU-145) and androgen-dependent prostate adenocarcinoma (LNCaP) cell lines by using WST-8 colorimetric method. This method was used for cell viability and cytotoxicity analysis. Compound 3b (SGK-720) [2-(1,8-diethyl-1,3,4,9tetrahydropyrano[3,4-b]indole-1-yl)acetic acid[(2,6-dichlorophenyl)methylene]hydrazides] showed 10.36, 5.24, 15.53 µM anticancer activity against PC3, DU145, LNCaP cancer cell lines, respectively. According to JC-1 mitochondrial membrane potential test and Annexin V/PI staining, 3b was found to have apoptotic effect on these cancer cells. It is concluded that compound 3b containing 2,6-dichloro substituents may be one of the candidate molecules to cope with prostate cancer.

Within the wide range of nitrogen-containing heterocyclic compounds, the derivatives of 1,8-naphthyridine (NPTR) have gained a rising interest due to their reported versatile biological activities. The derivatives of NPTR scaffold are found to invite special interest from researchers nowadays on the significance of their manifestations of multiple attractive pharmacological activities which establish them as an effective and versatile tool in pharmaceutical chemistry and drug discovery. The diverse biological activities mainly include anti-inflammatory, antimicrobial, antiviral, anticancer, antihypertensive and analgesic activities. Novel NPTR scaffold has emerged its potency to treat neurological diseases like depression and Alzheimer's disease. Further these agents possess different inhibitory activities, such as anti-HIV, anti-osteoporotic, αvβ3 antagonism, antimalarial, platelet aggregation, anti-oxidant, anti-allergic, gastric antisecretory, anticonvulsant, epidermal growth factor receptor (EGFR) inhibition, protein kinase inhibition, ionotropic properties, β3

Complex projects require specific project management (PM) competences development. However, while no complex projects have standards that are recognized to guide their management, complex projects do not have guides to deal with their complexity. To lead complex projects to success, this complexity must be measured quantitatively and, in our opinion, project management complexity assessment should be based on existing PM standards. In this work, the main project complexity assessment approaches based on PM standards are analyzed, observing that International Project Management Association (IPMA) approach is the closest to a tool that can be used as a complexity quantitative measurement system. On the other hand, several authors have shown that the inherent complexity of specific kind of projects must be measured in a particular way. The main objective of this research is to propose a project management complexity assessment tool for IT projects, providing a Complexity Index that measures the impact that complexity factors inherent to IT projects have under a specific complexity scenario. The tool combines the use of complexity factors defined by IPMA approach and the use of complexity factors found in the literature to manage inherent complexity of IT projects. All these factors were validated by expert survey and the tool was applied to a study case.

Redox mediators play a major role determining the photocurrent and the photovoltage in dye-sensitized solar cells (DSCs). To maintain the photocurrent, the reduction of oxidized dye by the redox mediator should be significantly faster than the back electron transfer between TiO2 and the oxidized dye. The driving force for dye regeneration with the redox mediator should be sufficiently low to provide high photovoltages. With our introduction of new copper complexes as promising redox mediators in DSCs both criteria are satisfied to enhance power conversion efficiencies. In this study, two copper bipyridyl complexes Cu((II/I))(dmby)2TFSI2/1 (0.97 V vs SHE, dmby = 6,6'-dimethyl-2,2'-bipyridine) and Cu((II/I))(tmby)2TFSI2/1 (0.87 V vs SHE, tmby = 4,4',6,6'-tetramethyl-2,2'-bipyridine) are presented as new redox couples for DSCs. They are compared to previously reported Cu((II/I))(dmp)2TFSI2/1 (0.93 V vs SHE, dmp = bis(2,9-dimethyl-1,10-phenanthroline). Due to the sma...