A disparate 3-D silver(I) coordination polymer of pyridine-3,5-dicarboxylate and pyrimidine with strong intermetallic interactions: X-ray crystallography,photoluminescence and antimicrobial activity

A polymeric silver(I) complex, [Ag₄(μ-pydc)₂(μ-pm)₂]_n (1) (pydc = pyridine-3,5-dicarboxylate and pm = pyrimidine), has been synthesized and characterized by elemental analysis, IR spectroscopy, thermal analysis, and single-crystal X-ray diffraction. X-ray crystallographic data of 1 revealed that pydc exhibits two different coordinaton modes that play a key role in the construction of the 3-D crystal network including Ag–carboxylate clusters in which close Ag–Ag distances exist. The magnitudes of close Ag–Ag interactions in second-order energy (E²) have been revealed by natural bond orbital analysis performed with single point energy calculation using the experimental geometry of 1. Furthermore, the luminescent properties of 1 show strong fluorescence with two emission maxima in the visible region. Also, 1 has antifungal activity on Candida albicans (MIC value, 4 μg mL^?1) and good antibacterial activity on micro-organisms (MIC value, 64–256 μg mL^?1).     

Ca(II) and Ba(II) methyl carbazate energetic complexes: syntheses,crystal structures,and properties

New energetic materials, [Ca(MCZ)₃(H₂O)₂](ClO₄)₂ and {[Ba₂(MCZ)₄(H₂O)₂(μ₁-ClO₄)₂(μ₂-ClO₄)₂]_0.5}_n, are synthesized and tried as alternatives to common primary explosives. Both the crystal structures were determined by single-crystal X-ray diffraction. The crystal of [Ca(MCZ)₃(H₂O)₂](ClO₄)₂ belongs to the monoclinic, P2₁/c space group, a = 14.168(3) Å, b = 8.5938(18) Å, c = 18.889(4) Å, β = 111.234(2)°, V = 2143.8(8) Å³, ρ = 1.6893 g cm^?3, and {[Ba₂(MCZ)₄(H₂O)₂(μ₁-ClO₄)₂(μ₂-ClO₄)₂]_0.5}_n belongs to the triclinic, P-1 space group, a = 7.166(2) Å, b = 10.461(2) Å, c = 11.738(4) Å, α = 110.563(5)°, β = 93.799(2)°, γ = 96.864(3)°, V = 812.4(4) Å³, ρ = 2.185 g cm^?3. Their thermal stabilities were investigated by differential scanning calorimetry (DSC), and exothermic peak temperatures with a heating rate of 10 °C min^?1 are 249.7 and 181.7 °C, respectively. Non-isothermal reaction kinetics parameters were calculated via both Kissinger’s method and Ozawa-Doyle’s method to work out E_K = 124.6 kJ mol^?1, lgA_K = 10.38, E_O = 126.7 kJ mol^?1 for the calcium complex and E_K = 100.3 kJ mol^?1, lgA_K = 9.50, E_O = 102.6 kJ mol^?1 for the barium complex. Additionally, the critical temperatures of thermal explosion, ΔS^≠, ΔH^≠, and ΔG^≠ were calculated as ?231.2 J K^?1 mol^?1, 120.417 kJ mol^?1, 236.728 kJ mol^?1 for the calcium complex and ?230.6 J K^?1 mol^?1, 96.723 kJ mol^?1, 195.938 kJ mol^?1 for the barium complex. As for their explosive nature, sensitivities toward impact and friction were tested. Both [Ca(MCZ)₃(H₂O)₂](ClO₄)₂ and {[Ba₂(MCZ)₄(H₂O)₂(μ₁-ClO₄)₂(μ₂-ClO₄)₂]_0.5}_n are insensitive to friction (>360 N); their impact sensitivities are acceptable (20 and 13 J). Both compounds are energetic complexes.     

Spectral and thermal characteristics of copper(II) carboxylates with fatty acid chains and their benzothiazole adducts

The carboxylato–Cu(II) complexes of type [Cu₂(RCOO)₄] and their benzothiazole adducts [Cu₂(RCOO)₄bt₂] (bt = benzothiazole, R = CH₃(CH₂) _n?2, n = 12, 14, 16, 18) form the main objectives of this study. The studied carboxylato–Cu(II) complexes are formed from dimeric units to polymeric chains (chromofor CuO₅). The structural changes are due to coordination of ligand (benzothiazole). The polymeric chains of carboxylato–Cu(II) complexes degraded to discrete centrosymetric tetracarboxylate-bridged dimmers (chromofor CuO₄N). These prepared compounds [Cu₂(RCOO)₄] and [Cu₂(RCOO)₄L₂] were submitted to measurements relating to spectral (IR, UV–Vis) and thermal properties (TG, DTA, DSC).     

A 1-D alternating copper(II) chain based on three acetate-bridging modes: synthesis,crystal structure,DNA binding and magnetic properties

A new 1-D alternating copper(II) polymer, [Cu₂(L)(OAc)₄]_n (1) (L = 5-chloro-2-(pyridine-2-yl)benzo[d]thiazole), has been isolated and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, and magnetic susceptibility. The complex crystallized in the triclinic space group P-1, a = 8.2277(16) Å, b = 9.4233(19) Å, c = 15.831(3) Å, α = 103.38(3)°, β = 99.95(3)°, γ = 92.70(3)°, V = 1171.3(4) Å³, and comprises a 1-D polymer linked by three kinds of acetate-bridging modes in an alternating manner. UV–visible and fluorescence spectra revealed that 1 is bound to CT-DNA in a partial intercalation mode. Through gel electrophoresis assays, 1 displayed an efficient oxidative cleavage activity on supercoiled plasmid DNA (pUC19) in the presence of H₂O₂. Magnetic measurements were performed from 2 to 300 K, and the experimental results were satisfactorily reproduced with J₁ = –160 ± 20 cm^?1, J₂ = 5.8 ± 0.2 cm^?1, zJ′ = 0.381 ± 0.005 cm^?1 and g = 2.1, showing antiferromagnetic coupling between Cu1 and Cu1i, ferromagnetic exchange between Cu2 and Cu2ii, and a weak ferromagnetic molecular field correction accounting for all interspecies interactions.     

Syntheses,structural characterizations and microbial activities of Ni(II) and Zn(II) 5-aminoisophthalate coordination polymers

Two coordination polymers with 5-aminoisophthalic acid (H₂aip), [Ni(μ-aip)(H₂O)₂(tmeda)]_n (1) and {H₂dap[Zn₂(μ-aip)(μ₃-aip)₂]?9H₂O}_n (2) (H₂aip = 5-aminoisophthalic acid, tmeda = N,N,N′-N′-tetramethylethylenediamine, dap = 1,3-diaminopropane) have been synthesized. Elemental and thermal analyses, magnetic susceptibilities, IR, AAS, mass and UV–vis spectroscopic studies have been performed to characterize the compounds. Nickel(II) has octahedral geometry by two oxygens of different carboxylates, bidentate, tmeda as bidentate chelating and two water ligands. Zn(II) has tetrahedral geometry by three oxygens of different carboxylate groups and one nitrogen by amine of aip. 1 crystallizes in the orthorhombic crystal system with space group Pccn and 2 in monoclinic crystal system with space group P2₁/c. Complex 2 exhibits photoluminescence properties in the solid state at room temperature. This study determined the susceptibility patterns of 1 and 2 against bacterial, yeast and mold micro-organisms. Antimicrobial activities were done on 12 different micro-organisms using the micro-dilution method. Tested microbial species were inhibited by 1 with a Minimum inhibitory concentrations (MIC) of 375–3000 μg mL^?1. Compound 2 showed antimicrobial activities against tested micro-organisms with a MIC of 188–1500 μg mL^?1. Compound 2 showed antibacterial activity against Legionella pneumophila sg1 375 μg mL^?1 (MIC value).     

Synthesis,characterization, and in vitro antiproliferative and antibacterial studies of tetraazamacrocyclic complexes of Co(II) and Cu(II) with pyromellitic acid

New cationic tetranuclear Co(II) and neutral binuclear Cu(II) complexes with tpmc (N,N′,N″,N″′-tetrakis-(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane) and bridging pyromellitate ligand pma (tetraanion 1,2,4,5-benzenetetracarboxylic acid) were isolated. The composition of the compounds is proposed based on elemental analyses (C, H, N, M=Cu, Co), molar conductivity determination, UV-Vis, FTIR, EPR, LC-MS and reflectance spectroscopy, magnetic measurements, cyclic voltammetry, as well as TG and DTA. It is proposed that in [Co₄(pma)(tpmc)₂](ClO₄)₄·6H₂O (1), cobalt(II) is six-coordinate out of cyclam rings and one OCO^? from pma participates in coordination with one Co(II). In the case of [Cu₂(pma)tpmc]?8H₂O (2), one OCO^? from pma bridges two Cu(II). The cytotoxic activity of 1 and 2 was tested against tumor cell lines human cervix adenocarcinoma (HeLa), estrogen-receptor-positive human breast cancer (MCF-7), human myelogenous leukemia (K562), and the human Caucasian Burkitt’s lymphoma (Ramos). The IC₅₀ values for 1 and 2 were within the range 44.66 ± 2.39 to 152.40 ± 2.28 μM, and from 140.88 ± 3.51 to 192.05 ± 2.09 μM, respectively. Both 1 and 2 were tested for antimicrobial activity. We determined that minimal inhibitory concentration for 1 against Staphylococcus aureus, Bacillus subtilis, and Klebsiella pneumoniae was 25 mM. Complex 2 did not express activity against tested microbial strains.     

Tricarbonylrhenium(I) complexes with the N,6-dimethylpyridine-2-carbothioamide ligand: combined experimental and calculation studies

Abstract

A new series of tricarbonyl complexes of rhenium(I) in the “2 + 1” system with the bidentate ligand N,6-dimethylpyridine-2-carbothioamide ((CH₃)NC₅H₄-CS-NH-CH₃, MeLH(Me)_NS) and a monodentate ligand (halides Cl, Br, or I, and the pseudohalide NCS anion) was synthesized. The use of mixed ligands led to the formation of neutral tricarbonylrhenium(I) complexes [Re(CO)₃(MeLH(Me)_NS)X] (X = Cl, Br, I, NCS) (1–4). Single-crystal X-ray diffraction was used to determine the crystal structures of all four compounds and those results were compared with molecular structures obtained from DFT calculations using the PBE0/def2-TZVPD approach. The complexes were also characterized by spectroscopic (FT-IR, NMR, and UV–vis) and analytical (HPLC, TGA, EA, ESI-MS) techniques. IR and UV–vis spectra were also calculated by DFT and TD-DFT methods. The cytotoxicity of these complexes was estimated using human ovarian cancer cell lines (A2780 and A2780cis), cervical cancer cells (HeLa), and non-cancerous human embryonic kidney cells (Hek-293). The toxicity of most complexes was moderate or low toward cancer cell lines (IC₅₀ = 46–231 μM) and similar against non-cancerous cells (IC₅₀ = 41-121 μM). Only the complex with chlorido ligand remarkably inhibited growth of ovarian cancer cells (IC₅₀ = 3 and 12 μM for A2780 and A2780cis, respectively). The cytotoxicity of 1 was higher than that of cisplatin.     

Ferromagnetic copper(II)–copper(II) interaction in a single chlorido and dicyanamido bridged mixed–valence copper(I/II) 2-D polymer generated by in situ partial reduction of copper(II)

A mixed-valence 2-D Cu(I/II) complex, [{Cu(II)(dmen)(μ-Cl)(μ_1,5-dca)}{Cu(I)(μ_1,5-dca)}]_n (1) (dmen = N,N-dimethylethylenediamine, dca = dicyanamide = [N(CN)₂]^?), has been synthesized by in situ partial reduction of Cu(II) to Cu(I) using benzoin (2-hydroxy-1,2-di(phenyl)ethanone) as reductant. Complex 1 was characterized by spectroscopic techniques, single crystal X-ray diffraction, and low temperature magnetic measurements. Structural investigation reveals that 1 represents a mixed-valence 2-D coordination polymer formed by parallel 1-D [Cu(II)(dmen)(Cl)Cu(I)(μ_1,5-dca)₂]_n chains running along the b axis, where chloride bridges Cu(II) ions of adjacent polymers through long connections (2.8401(1) Å) to form a 2-D network. The metal centers have two different geometrical environments (distorted square pyramidal and distorted trigonal planar geometries for Cu(II) and Cu(I), respectively). The Cu(II) ions in [Cu(II)(dmen)(μ-Cl)(dca)]_n are interconnected through single chloride bridges while within the [Cu(I)(μ_1,5-dca)]_n units, the dca connects adjacent Cu(I) ions through μ_1,5-dca bridges. Magnetic susceptibility measurements reveal weak ferromagnetic interactions (J = +0.3 cm^?1) within the chlorido-bridged Cu(II) regular chain present in 1. Simultaneous presence of μ_1,5-dca and single chlorido bridges with ferromagnetic coupling is believed to be unique in mixed-valence Cu(I)/Cu(II) complexes.     

The synthesis,characterization, and theoretical hydrogen gas adsorption properties of copper(II)-3,3′-thiodipropionate complexes with imidazole derivatives

Three new coordination polymers, [Cu(μ₃-tdp)(im)₂]_n (1), {[Cu(μ₃-tdp)(1-mim)₂]·0.5H₂O}_n (2) and {[Cu₂(μ₃-tdp)₂(4-mim)₄]·H₂O}_n (3) [tdpH₂ = 3,3′-thiodipropionic acid, im = imidazole, 1-mim = 1-methylimidazole and 4-mim = 4-methylimidazole], have been prepared and characterized by spectroscopic techniques (IR and UV–Vis), elemental analyzes, magnetic measurements, thermal analyzes, and single-crystal X-ray diffraction. Complexes 1–3 crystallize in the monoclinic system with space groups of C2/c and P2₁/c, respectively. In 1–3, tdp is a bridging ligand to form 1-D chains, which are extended into a 2-D layer by hydrogen bonding and π···π interactions. The 3,3′-thiodipropionate exhibits an unexpected coordination mode in 1–3. Simulations were used to assess the potential of the complexes in H₂ storage applications.     

Syntheses,crystal structures and solvatochromic properties of dinuclear oxalato-bridged copper(II) complexes

Three dinuclear copper(II) complexes, [Cu₂(L¹)₂(μ-ox)](ClO₄)₂?2(CH₃CN), [Cu₂(L²)₂(μ-ox)](ClO₄)₂?H₂O, and [Cu₂(L³)₂(μ-ox)](ClO₄)₂ where ox = oxalato; L = N,N-dimethyl,N′-benzylethane-1,2-diamine, L¹, N,N-diethyl,N′-benzylethane-1,2-diamine, L², N,N-diisoprophyl,N′-benzylethane-1,2-diamine, L³, were prepared and characterized by elemental analyses, spectral (IR, UV–Vis) data and molar conductance measurements. The crystal structures of [Cu₂(L¹)₂(μ-ox)](ClO₄)₂?2(CH₃CN) and [Cu₂(L³)₂(μ-ox)](ClO₄)₂ have been determined by single-crystal X-ray analysis. Solvatochromic behaviors were investigated in various solvents, showing positive solvatochromism. The effect of steric hindrance around the copper ion imposed by N-alkyl groups of the diamine chelates on the solvatochromism property of the complexes is discussed. Solvatochromism was also studied with different solvent parameter models using stepwise multiple linear regression method.     

Synthesis,structure, anticancer activities,and DNA-binding properties of a 1-D polymeric copper(II) complex alternately bridged by oxamide and terephthalate

A 1-D polymeric copper(II) complex alternately bridged by N,N′-bis(N-hydroxyethylaminopropyl)oxamide (heap^2?) and terephthalate (tpa^2?), [Cu₂(heap)(tpa)] _n , has been synthesized and characterized by single-crystal X-ray diffraction. The crystal structure reveals that the asymmetric unit of the copper(II) polymer is half a dinuclear copper(II) complex, [Cu₂(heap)(tpa)], in which Cu(II) is located in a square-pyramidal coordination environment. Separations of Cu(II) through heap^2? and tpa^2? bridges are 5.2459(6) and 11.1375(6)?Å, respectively. The complex chains, accompanied with glide planes parallel to the a0c plane, can be classified to two groups according to their extending direction. Hydrogen bonds occur between a complex chain and any adjacent ones in the other orientation. Consequently, a 3-D supramolecular network is completed. The polymeric copper(II) complex exhibits potent anticancer activities against human hepatocellular carcinoma cell SMMC-7721 and human lung adenocarcinoma cell A549 tested by sulforhodamine B assays. The interactions of the polymeric copper(II) complex with herring sperm DNA (HS-DNA) are investigated by using electronic absorption titration, fluorescence titration, electrochemical titration, and viscometry measurements. The results suggest that the polymeric copper(II) complex interacts with HS-DNA via intercalation with intrinsic binding constant of 1.8?×?10^6?(mol?L^?1)^?1.     

Copper(I)-1,1,1-tris(diphenylphosphinomethyl)ethane complexes with different coordination modes tuned by auxiliary ligands and their spectroscopic properties

Three mono-, bi- and tetranuclear copper(I) complexes, [Cu(phen)(triphos-O)]BF₄ (1) (phen = 1,10-phenanthroline, triphos = 1,1,1-tris(diphenylphosphinomethyl)ethane), [Cu₂(bipy)(triphos)₂](BF₄)₂ (2) (bipy = 4,4′-bipyridine), and [Cu₄(MeOC^N^N)₄(triphos)₂(bipy)](BF₄)₄ (3) (MeOC^N^N = 6-(4-methoxyphenyl)-2,2′-bipyridine), have been synthesized and characterized by NMR spectroscopy, electrospray ionization, and matrix-assisted laser desorption ionization time-of-flight mass spectrometries, elemental analysis, and X-ray crystal analysis. The crystal structure investigation revealed the copper ions of the complexes have pseudo-tetrahedral coordination geometry. The electronic absorption spectra of 1, 2, and 3 contain low-energy bands at 350–500 and 400–650 nm, which are assigned to d(Cu) → π*(phen or bipy) and a mixture of d(Cu) → π*(MeOC^N^N) and d(Cu) → π*(bipy) transitions, respectively. Complex 2 displays a strong, long-lived solid-state emission with a maximum at 555 nm and lifetime of 13.6 μs at room temperature. Photoinduced electron-transfer properties of 2 and 3 involving nanosecond time-resolved absorption spectroscopy and electron spin resonance techniques were studied.     

Synthesis,crystal structure,and DNA-binding studies of a one-dimensional copper(II) polymer bridged both by oxamidate and thiocyanato ligands

A new one-dimensional copper(II) polymer, [Cu₄(dmapox)₂(SCN)₄(CH₃OH)₂] _n , where dmapox is the dianion of N,N′-bis[3-(dimethylamino)propyl]oxamide, was synthesized and characterized by elemental analysis, conductivity measurement, IR, and electronic spectral studies. The crystal structure of the copper(II) complex has been determined by X-ray single-crystal diffraction. The complex crystallizes in triclinic, space group P ? 1 and exhibits infinite one-dimensional copper(II) polymeric chain bridged both by bis-tridentate μ-trans-dmapox and μ-1,3-thiocyanato ligand. The environment around the copper(II) atom can be described as distorted square-pyramid. The Cu···Cu separations through the oxamidate and thiocyanato bridges are 5.246(2) Å (Cu1–Cu1ⁱ), 5.2649(14) Å (Cu2–Cu2ⁱⁱ), and 5.8169(15) Å (Cu1–Cu2), respectively. The interaction of the copper(II) complex with herring sperm DNA (HS-DNA) has been investigated by using absorption and emission spectral and electrochemical techniques and viscometry. The results reveal that the copper(II) complex may interact with DNA in the mode of groove binding with the intrinsic binding constant of 2.56 × 10⁵ M^?1.     

Synthesis and spectral studies of macrocyclic Cu(II) complexes by reaction of various diamines,copper(II) perchlorate and 1,4-bis(2-carboxyaldehyde phenoxy)butane

Six macrocyclic complexes, were synthesized by reaction of 1,4-bis(2-carboxyaldehyde phenoxy)butane and various amines and their copper(II) perchlorate complexes were synthesized by template effect reaction of 1,4-bis(2-carboxyaldehyde phenoxy)butane, Cu(ClO₄)₂?·?6H₂O and amines. The metal-to-ligand ratios were found to be 1?:?1. Cu(II) metal complexes are 1?:?2 electrolytes as shown by their molar conductivities (Λ_M) in DMF (dimethyl formamide) at 10^?3?M. The Cu(II) complexes are proposed to be square planar based on elemental analysis, FT–IR, UV–Vis, magnetic susceptibility measurements, molar conductivity measurements, and mass spectra.     

Mono-, di-, and trinuclear phosphonate oxygen-bridged copper(II) complexes: syntheses,structures, and properties

Reactions of copper salts, zoledronic acid, and 2,2′-bipyridine/1,10-phenanthroline in aqueous ethanolic solutions afforded four phosphonate oxygen-bridged copper complexes, Cu(bipy)(H₄zdn)(HSO₄) (1), [Cu₂(bipy)₂(H₂zdn)(H₂O)(Cl)]·4H₂O (2), [Cu₂(phen)₂(H₂zdn)(H₂O)(Cl)]·2.5H₂O (3), and [Cu₃(bipy)₃(H₄zdn)(H₂zdn)(SO₄)]·5H₂O (4) (H₅zdn = zoledronic acid, bipy = 2,2′-bipyridine, phen = 1,10-phenanthroline). The copper centers of 1–4 have square pyramidal coordination geometries. The Cu(II) ions are coordinated to bipy/phen, zoledronate, and HSO₄^?/Cl^? forming mononuclear units for 1, dinuclear for 2 and 3, and trinuclear for 4. These building units are further extended into 3-D supramolecular networks via multiple hydrogen bond interactions. Temperature-dependent magnetic properties of 2 and 4 suggest weak antiferromagnetic coupling (J = ?4.53(8) cm^?1 for 2, J = ?1.69(4) cm^?1 for 4). The antitumor activity of 2 was evaluated against the human lung cancer cell line and indicates effective time- and dose-dependent cytotoxic effects.     

Thermal properties and CT-DNA/BSA binding behavior of a binuclear Cu(II) complex with acylhydrazone containing naphthalene ring

A novel Cu(II) complex [Cu₂L₂(NO₃)₂] with 2-hydroxy-1-naphthaldehyde-(4’hydroxy)phenylacetyl hydrazone (C₁₉H₁₄N₂O₂·H₂O, HL) was synthesized. The structure of [Cu₂L₂(NO₃)₂] was characterized by X-ray single-crystal diffraction and can be described as a distorted rectangular pyramid with binuclear coordination. IR, UV–vis and EPR spectra are used to discuss the structure of Cu(II) complex in different conditions. Magnetic properties were determined by EPR spectra and magnetic susceptibility studies, showing magnetic exchange interaction and weak antiferromagnetic exchange between two Cu(II) ions. The apparent activation energy (E_a) of thermal decomposition of compounds indicated that the thermal stability of [Cu₂L₂(NO₃)₂] is better than HL. The CT-DNA binding behavior of compounds was determined by UV–vis absorption and viscosity measurements and the results confirmed an intercalative binding mode with CT-DNA. K_b obtained was 6.24(±0.12) × 10⁶ M^?1 and 3.09(±0.006) × 10⁶ M^?1 for [Cu₂L₂(NO₃)₂] and HL, respectively, revealing that the binding ability of [Cu₂L₂(NO₃)₂] with CT-DNA was stronger. The thermogenic curves of compounds interacting with CT-DNA were monitored by microcalorimetry, showing they were all endothermic reactions with reaction within 27–42 min; interaction enthalpies (ΔH) of [Cu₂L₂(NO₃)₂] and HL were 30.3 and 4.31 kJ mol^?1. Binding studies with BSA were evaluated by fluorescence spectroscopy and the same relative interactions were found comparing with the above CT-DNA experiments.     

Synthesis,structure, and thermal decomposition of two copper coordination compounds [Cu(DAT)2(PA)2] and [Cu(DAT)2(HTNR)2] with nitrogen rich 1,5-diaminotetrazole (DAT)

Both [Cu(DAT)₂(PA)₂] (1) and [Cu(DAT)₂(HTNR)₂] (2) were prepared from 1,5-diaminotetrazole (DAT) and copper trinitrophenol, 1 for picrate (PA) and 2 for styphnate acid (2,4,6-trinitro resorcinol, TNR), and were characterized by elemental analysis, FT-IR spectroscopy, and single crystal X-ray diffraction. The space group of these compounds is P2₁/c (monoclinic). The lattice parameters are similar [a = 11.405(3) Å, b = 14.867(3) Å, c = 8.099(2) Å for 1 and a = 12.262(3) Å, b = 14.900(3) Å, c = 7.243(2) Å for 2], except the β = 106.257(3)° in 1 and β = 92.989(4)° in 2. Both have extended structures due to hydrogen bonds, but there are some differences because of the ligands induced effect. Differential scanning calorimetry analysis shows that two exothermic processes take place in both complexes, the first peak temperatures are 488.2 K for 1 and 519.2 K for 2. The kinetic parameters of the first exothermic process were studied by using Kissinger’s method and Ozawa’s method, in which the enthalpy of formation (?7346 and ?5706 kJ M^?1), critical temperature of thermal explosion (475.0 and 515.8 K), entropy of activation (ΔS^≠), enthalpy of activation (ΔH^≠), and free energy of activation (ΔG^≠) were calculated and obtained as ?117.25 J K^?1 M^?1, 140.64 kJ M^?1, 196.44 kJ M^?1 and ?219.1 J K^?1 M^?1, 383.56 kJ M^?1, 495.34 kJ M^?1 for 1 and 2, respectively. The sensitivity test results showed that both compounds were sensitive to impact (<5 J) and flame (>20 cm) rather than friction.     

Synthesis,crystal structure,and Helicobacter pylori urease inhibition of a dicyanoamide bridged Cu(I/II) complex

A dicyanoamide-bridged polymeric copper(I/II) complex, [Cu^II(sal)(bipy)Cu^I(dca)₂]_n, was prepared by reaction of 5-methylchlorosalicylaldehyde (Hsal), 2,2′-bipyridine (bipy), sodium dicyanoamide (Nadca), and copper perchlorate in methanol. The complex was characterized by elemental analyses, infrared and electronic spectroscopy, and single-crystal X-ray determination. Cu^II has a square pyramidal coordination, and Cu^I has triangular coordination. The complex showed high urease inhibitory activity with IC₅₀ value of 0.16 ± 0.23 μM.     

TRANSITION METAL COMPLEXES WITH HYDRAZIDES AND HYDRAZONES. PART 81. X-RAY CRYSTAL STRUCTURE OF A CATENA-POLYBROMO (ACETONE-1-NAPHTHOYLHYDRAZONE) COPPER(II)-COPPER(I) COMPLEX

Abstract

The title compound [Cu₃Br₄C₂₈H₂₈N₄O₂] is a type of polymeric three-centre octahedral-trigonal planar coordination complex. The copper(II) atom located at a centre of symmetry is six-coordinate with two bidentate (N3, O1) ligands of acetone-1-naphthoylhydrazone forming the equatorial plane and two bromine ions in axial positions (Cul-Brl = 2.946(1)Å). The ligands are in trans positions. The Cu(I) atoms are in trigonal planar coordination by two bridging Br^? ions (Cu2-Br2 = 2.412(1)Å, Cu2-Br2? = 2.407(2)Å) which connect two Cu(I) atoms and a third bromine ion shared with the octahedral Cu(II) ion (Cu2-Br1 = 2.304(1)Å). The arrangement forms an infinite chain along the b axis.     

Synthesis,characterization, molecular modeling,and DNA interaction studies of a Cu(II) complex containing drug of chronic hepatitis B: adefovir dipivoxil

A new copper(II) complex [Cu(adefovir)₂Cl₂], where adefovir = adefovir dipivoxil drug, was synthesized and characterized by using different physicochemical methods. Binding interaction of this complex with calf thymus DNA (ct-DNA) has been investigated by multi-spectroscopic techniques and molecular modeling study. The complex displays significant binding properties of ct-DNA. The results of fluorescence and UV–vis absorption spectroscopy indicated that, this complex interacted with ct-DNA in a groove-binding mode, and the binding constant was 4.3(±0.2) × 10⁴ M^?1. The fluorimeteric studies showed that the reaction between the complex and ct-DNA is exothermic (ΔH = 73.91 kJ M^?1; ΔS = 357.83 J M^?1 K^?1). Furthermore, the complex induces detectable changes in the CD spectrum of ct-DNA and slightly increases its viscosity which verified the groove-binding mode. The molecular modeling results illustrated that the complex strongly binds to the groove of DNA by relative binding energy of the docked structure ?5.74 kcal M^?1. All experimental and molecular modeling results showed that the Cu(II) complex binds to DNA by a groove-binding mode.