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A series of complexes [Cu(L)(CH3COO)2]·nH2O (L: isonicotinic acid 2-(2-hydroxy-8-substituted-tricyclo[7.3.1.02.7]tridec-13-ylidene)-hydrazones) were synthesised and characterised. The features of complexes have been assigned from microanalytical data, ESI–MS, IR, UV–Vis–NIR and EPR spectra, as well as thermal analysis. The ligands (hydrazones and acetate) act as chelate in the octahedral distorted complexes of Cu(II). The thermal analysis evidenced complex thermal transformations such as thermolises and oxidative degradation of hydrazone moiety as well as acetate into carbonate transformation, followed by carbonate decomposition up to CuO. The complexes were evaluated for their interaction with microbial and immortalised human cells, in order to formulate some potential biomedical applications, beyond the antimycobacterial activity. [ABSTRACT FROM AUTHOR]

A novel series of complexes ML(ClO4)·nH2O (M: Co, Ni, Cu, Zn; HL: 2-[(E)-(1H-1,2,4-triazol-3-ylimino)methyl]phenol) have been synthesized and characterized as mononuclear species. The features of complexes have been assigned from microanalytical, FAB-MS, IR, UV-Vis-NIR, EPR and magnetic data. The IR spectra indicate the chelate behaviour of Schiff base and the perchlorate presence either as free ion or as ligand. Electronic and magnetic data are consistent with hexa-coordination of Co(II) and Ni(II) and penta-coordination for Cu(II) ions in complexes. The simultaneous TG-DSC/MS measurements evidenced processes as water (hydration or coordination) elimination, perchlorate decomposition as well as Schiff base both fragmentation and oxidative degradation. The in vitro screening of the antimicrobial behaviour on Gram-positive and Gram-negative bacteria, as well as on fungal strains, indicates a good activity for Cu(II) and Zn(II) complexes against both planktonic or adherent cells. Moreover, Cu(II) complex also exhibited a promising antiproliferative activity on HT 29 cell line. [ABSTRACT FROM AUTHOR]

A series of complexes [Ca(HL)(OH)]Cl·4HO ( 1), [CuL]·2HO ( 2) and [Cu{Ca(L)(OH)}]Cl·HO ( 3) (HL: 2-hydroxy-8-methyl-tricyclo[7.3.1.0]tridec-13-N-4′(benzo-15-crown-5-ether)-imine) were synthesised and characterised. The features of complexes have been assigned from microanalytical data, IR, UV-Vis-NIR and EPR spectra, magnetic data at room temperature as well as thermal analysis. The ligand coordinates through azomethinic nitrogen and hydroxylic oxygen at Cu(II) and through etheric oxygen at Ca(II). The electronic and EPR spectra suggest a square planar stereochemistry for Cu(II). The thermal analysis evidenced that thermal transformations are complex processes according to DTG and DTA curves including (crystallisation or coordination) water elimination, thermolyses and oxidative degradation of Schiff base. The results of the biological assays revealed that the complexes exhibited good antimicrobial activity against planktonic and sessile bacterial and fungal strains. [ABSTRACT FROM AUTHOR]

A series of complexes of type M(pmtp)(CHCOO)·nHO (( 1) M: Co, n = 4.5; ( 2) M: Ni, n = 3.5; ( 3) M: Cu, n = 0.5; ( 4) M: Zn, n = 0; pmtp: 5-phenyl-7-methyl-1,2,4-triazolo[1,5- a]pyrimidine) were synthesised by one-pot condensation. The complexes were characterized by elemental analysis, ESI-MS, IR, UV-Vis-NIR, EPR spectra, magnetic susceptibility at room temperature as well as thermogravimetric analysis. The modifications in the IR spectra of complexes are in accordance with the condensation process and indicate the triazolopyrimidine coordination as unidentate. The electronic and EPR spectra together with magnetic moments indicate an octahedral stereochemistry for paramagnetic ions, except for Cu(II) with a square pyramidal geometry. Processes such as water elimination, acetate into carbonate transformation, as well as oxidative degradation of the triazolopyrimidine derivative were evidenced during thermal decomposition. The complexes exhibited an improved antimicrobial activity in comparison with the ligand, on both planktonic and biofilm-embedded microbial cells. The best antimicrobial activity in both susceptible and resistant strains was obtained for complex ( 3) followed by complex ( 1), which can be related to both oxidation state and stereochemical versatility. At high concentrations, the Cu(II) complex exhibits both cytotoxicity on HT 29 tumour cell line and anti-inflammatory activity. [ABSTRACT FROM AUTHOR]

The Schiff base N,N′-bis-(3-methoxy-salicyliden)- o-tolidine (HL) derived from o-vanillin and 3,3`-dimethylbenzidine has been synthesized and structurally characterized. The crystal structure shows that the planar molecular units are arranged in sheets assembled through hydrogen bonds and π-π stacking interactions. New Ni(II), Cu(II), Zn(II), and Cd(II) complexes with HL were synthesized and characterized by microanalytical, molar conductivities, ESI MS, IR, UV-Vis-NIR, and EPR spectra, magnetic data at room temperature as well as thermal analysis. IR data are in accord with divergent bischelate nature of ligand that coordinates as anion through azomethine nitrogen and phenolic oxygen. The electronic spectra correlated with magnetic susceptibility measurements, and EPR data indicate an octahedral stereochemistry for Ni(II) complex and a tetrahedral one for Cu(II) complex. Processes such as water elimination, thermolyses, and oxidative degradation of Schiff base were evidenced during thermal analysis. All these processes lead to the most stable metallic oxides as final products. [ABSTRACT FROM AUTHOR]

A new derivative 5-phenyl-7-methyl-1,2,4-triazolo[1,5- a]pyrimidine (pmtp) was synthesised by [1 + 1] condensation of benzoylacetone and 3-amino-4H-1,2,4-triazole. Single crystal X-ray diffraction revealed that the pmtp crystallises in monoclinic system, P21/n spatial group. In order to modulate the biological activity, new species M(pmtp)Cl·nHO (M: Co, n = 2; M: Ni, n = 3; M: Cu, n = 1; M: Zn, n = 0) were synthesised by one-pot method. Chemical analysis, molar conductivities, IR, UV-Vis-NIR and EPR spectroscopy, as well as magnetic data recorded at room temperature provided useful information concerning the molecular formula, stereochemistry and ligand coordination mode. The modifications at heating and also the thermodynamic effects that accompany them were investigated by thermal analysis. The nature of the gaseous products formed in each step was evidenced by simultaneous TG/DSC/EGA measurements. Processes as water and chloride elimination, fragmentation and oxidative degradation of the triazolopyrimidine derivative were observed during the thermal studies. The final residue was the most stable metallic oxide as X-ray powder diffraction indicates. Zinc (II) and copper (II) complexes exhibited the most significant antimicrobial activity against a wide spectrum of Gram-positive and Gram-negative bacterial strains, both reference and clinical resistant ones, in planktonic and biofilm state. The minimal biofilm eradication values were two to four times lower than the minimal inhibitory concentrations demonstrating the potential of the obtained complexes to act as anti-pathogenic agents. [ABSTRACT FROM AUTHOR]

A hydrous complex of erbium coordinated with glycine sodium perchloric acid, Er( μ -Gly)(HO)·Na(ClO)(HO)·4HO (Gly = glycine), was synthesized firstly and characterized by X-ray single-crystal diffraction. The complex crystallizes centrosymmetrically in the triclinic P-1 space group [ a = 9.2959 (5), b = 12.1756 (7) Å, c = 13.9928 (7) Å, V = 1367.67 (13) Å, Z = 1]. The low-temperature molar heat capacities and thermodynamic properties of the complex were studied with adiabatic calorimetry. The thermodynamic functions, [ H - H ] and [ S - S ], were derived in the temperature range from 80 to 370 K with a temperature interval of 5 K. Thermal decomposition behavior of the complex in nitrogen atmosphere was studied by thermogravimetric analysis and differential scanning calorimetry. Graphical Abstract: [ABSTRACT FROM AUTHOR]

A novel thiourea derivative 2-chloro- N-((5-chloropyridine-2-yl)carbamothioyl)benzamide ligand (HL) and its transition metal complexes (ML; M: Co, Ni and Cu) were synthesized and characterized by elemental analysis, FTIR and H-NMR techniques. The HL was also characterized by single-crystal X-ray diffraction method. It crystallizes in the monoclinic space group P 1 2/ c 1, with Z = 4, and unit-cell parameters, a = 6.7140(15) Å, b = 13.667(3) Å, c = 15.524(4) Å. Thermal decomposition of the complexes has been studied by TG/TDA combined system. Cyclic voltammetry technique was utilized to understand the electrochemical behavior of the complexes. Furthermore, the complexes were screened for their antioxidant activities which were measured by using the DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)) assays. [ABSTRACT FROM AUTHOR]

A heptanuclear trigonal prismatic polyhedron, [EuCu(μ-OH)(Gly)Im](ClO)·3HO, was synthesized and characterized by elemental analysis and X-ray single-crystal diffraction. The complex crystallize is the rhombohedral R3 space group ( a = b = 15.8673 Å, c = 23.4038 Å, V = 5103.0(6) Å, Z = 3). In the clusters, Eu ions are situated in the center of a prism formed by six copper atoms and coordinate to nine oxygen atoms with a tricapped trigonal prismatic coordination polyhedron. Six glycinato ligands and six imidazole terminal ligands (each coordinates to one Cu) were used in the construction of the cluster. The low-temperature molar heat capacity, C, and thermodynamic properties of the complex were studied with an adiabatic calorimeter from 80 to 370 K. The thermodynamic functions [ H- H] and [ S- S] were derived in the temperature range from 80 to 370 K with a temperature interval of 5 K. The thermal properties of the complex from 300 to 800 K were studied by DSC and TG in nitrogen atmosphere. [ABSTRACT FROM AUTHOR]

Two pyridine carboxaldehyde-derived schiff bases and their copper, nickel and manganese complexes have been synthesized, characterized by spectroscopic and thermal analyses. For the antimicrobial activity experiments, the microorganisms B. megaterium, K. pneumoniae, E. coli, P. aeruginasa, S. aureus, B. subtilis and E. aerogenes have been used. Nickel and copper complex compounds of ligand L were recorded as the most effective coordination compounds as antimicrobial. Catalytic activity results revealed that the both manganese and nickel complexes were moderately more effective for the oxidation reactions of cyclohexene and styrene. [ABSTRACT FROM AUTHOR]

A series of complexes [MLCl(OH)]· mHO (M: Co, n = 0, m = 1; M: Ni, n = 2, m = 0; M: Cu, n = 0, m = 0; M: Zn, n = 0, m = 1; HL·HO: 2-[(E)-1 H-1,2,4-triazol-3-ylimino)methyl]phenol) were synthesised and characterised. The features of complexes have been assigned from microanalytical, thermal, IR, UV-Vis-NIR, EPR spectroscopy as well as magnetic data at room temperature. The electrochemical behaviour of the complexes was also investigated by cyclic voltammetry. The simultaneous TG/DTA experiments of these in flowing air atmosphere evidenced the occurrence of water or chloride as well as oxidative degradation of the Schiff base. The final product of decomposition was the most stable metal oxide as powder X-ray diffraction indicates. The complexes exhibited an improved antibacterial activity in comparison with the ligand towards both planktonic as well as biofilm embedded cells. The Cu(II) and Zn(II) complexes exhibited an inhibitory effect on the tumor cell lines growth, as revealed by the increased G2 phase and percentage of apoptotic/necrotic cells. [ABSTRACT FROM AUTHOR]

A new ligand entitled as N,N'-bis-[3-(4-dimethylaminophenyl)-allylidene]-propane-1,3-diamine(L) was synthesized and then used for preparation of a new series of zinc halide/pseudohalide complexes with general formula of ZnLX, wherein X is chloride, bromide, iodide, thiocyanate, and azide anions. The ligand and its complexes were characterized by analytical and spectral data such as conductivity measurements, elemental analysis, FT-IR, UV-Visible, and H NMR spectroscopy. Elemental analyses (CHN) suggested that the reaction between ligand and zinc salts has been occurred in 1:1 molar ratio. The low values for molar conductivities of the zinc complexes indicated non-electrolyte nature for them. Spectral data confirmed that the ligand behaves as a bidentate chelate and is coordinated via nitrogen atoms of imine groups. Moreover, thermal analysis of ligand and its complexes were studied in the range of room temperature to 1,000 °C with a heating rate of 10 °C min. TG/DTG/DTA plots show that the ligand and its complexes are thermally decomposed via 2-4 thermal steps. In final, the ligand and its complexes were subjected to antimicrobial screening by determining of minimum inhibitory concentration (MIC) and inhibition zone of the microbial growth. Also DNA cleavage potential of all compounds was evaluated by gel electrophoresis method. [ABSTRACT FROM AUTHOR]

A series of novel five coordinated mercury(II) complexes of a new recently synthesized tridentate ligand are presented. The mercury(II) complexes were characterized by various spectral and physical techniques such as FTIR, UV-visible, H and C NMR spectra, thermal analyses, and decomposition temperature and conductivity measurement. Also nanostructure size of titled mercury coordination compounds have been prepared by the reaction of ligand and mercury salts under ultrasonic conditions. The nanostructure size of the complexes was confirmed by XRD patterns, scanning electron microscopy, and transmission electron microscopy. According to the mentioned analyses, the molecular formula of HgLX (X = halide and/or pseudo-halide anions and L = ligand) was suggested for the complexes. Thereafter all mercury(II) complexes were tested for their in vitro antibacterial activities against two Gram-positive ( Staphylococcus aureus and Bacillus subtilis) and two Gram-negative ( Escherichia coli and Pseudomonas aeruginosa) bacterial strains. Also in vitro antifungal activities of them against Candida albicans and Aspergillus niger were investigated. The results indicated that all compounds can act as antibacterial and antifungal agents. Moreover, thermal behaviors of the complexes were studied in the range of 20-900 °C. Thermogravimetric study indicated that the mercury complexes are thermally degraded via 3-9 thermal steps. [ABSTRACT FROM AUTHOR]

Three new coordinative compounds of the type [Co(en)CO]·0.75HO ( 1) and [M(en)(HO)]CO (( 2) M:Ni, ( 3) M:Cu; en: ethylenediamine) were synthesized and characterized. The IR and UV-Vis spectral data indicate that ethylenediamine acts as chelate, while carbonate ions act as bidentate chelate ligand for ( 1)/counter ion for ( 2) and ( 3) generating complexes with octahedral stereochemistry. The thermal behavior provided confirmation of the complexes composition, as well as the number and the nature of water molecules and the intervals of thermal stability. The biological assays revealed a good activity against Enterococcus faecium for copper complex. [ABSTRACT FROM AUTHOR]

A series of complexes of type [ML(CHCOO)(OH)] ( M: Co, Ni; HL: 2-[(E)-1H-1,2,4-triazol-3-ylimino)methyl]phenol)) and [ML(CHCOO)(OH)] ( M: Cu, n = 2; M: Zn, n = 0) were synthesised by template condensation. The compounds were characterised with microanalytical, ESI-MS, IR, electronic, EPR spectra and magnetic data at room temperature. Based on the IR and ESI-MS spectra, a dinuclear structure with the acetate as bridge was proposed for Cu(II) and Zn(II) complexes. The dinuclear structure of Cu(II) complex is also consistent with both magnetic behaviour and EPR spectrum. The thermal analyses have evidenced processes as water elimination, acetate decomposition, as well as oxidative degradation of the Schiff base. The final decomposition product was the most stable metal oxide as indicated by powder X-ray diffraction. The cobalt and copper compounds exhibited a broad spectrum of antibacterial activity towards both planktonic and biofilm-embedded cells. The complexes exhibit a low cytotoxicity except for Cu(II) species that induces the early apoptosis for the HEp 2 cells. [ABSTRACT FROM AUTHOR]

Novel complexes of MLCl· nHO type (M:Ni, n = 4; M:Cu, n = 3 and M:Zn, n = 0; L: ligand resulted from 1,4-phenylenediamine, 3,6-diazaoctane-1,8-diamine and formaldehyde one-pot condensation) were synthesized and characterised by microanalytical, ESI-MS, IR, UV-Vis, H NMR and EPR spectra, magnetic data at room temperature and molar conductivities as well. The electrochemical behaviour of complexes was investigated by cyclic voltammetry. Simultaneous TG/DTA measurements were performed in order to evidence the thermal behaviour of the obtained complexes. Processes such as water elimination, fragmentation and oxidative degradation of the organic ligand as well as chloride elimination occurred during thermal decomposition. The antimicrobial assays demonstrate that the compounds exhibited good antibacterial activity, especially against S. aureus and E. coli strains, the most active being the copper(II) complex, which also exhibited the most prominent anti-biofilm effect, suggesting its potential use for the development of new antimicrobial agents. The biological activity was correlated with log P values. All complexes disrupt the membrane integrity of HCT 8 tumour cells. [ABSTRACT FROM AUTHOR]

New complexes ML(CNS)· nHO [M = Ni, n = 0.5; M = Cu, n = 4.5; M = Zn, n = 0.5, HL: 6-mercapto-(1,4,8,11-tetraazaundecanyl)-6-carboxylic acid)] have been synthesised, chemical analysed, and characterised by different spectroscopic techniques (IR, UV-Vis-NIR, H NMR, EPR, ESI-MS), and magnetic measurements. Based on the IR spectra a dinuclear structure with the 1,3-CSN coordination was proposed for Ni(II) and Cu(II) complexes. The dinuclear structure of Cu(II) complex is also consistent with both magnetic behaviour and EPR spectrum. According to TG, DTG and DTA curves the thermal transformations are complex processes, including dehydration, Mannich base oxidative degradation and thiocyanate decomposition. The final product of decomposition is the most stable metallic oxide, as XRD data indicates. The new complexes were also screened for their microbicidal and antibiofilm properties. [ABSTRACT FROM AUTHOR]

Carbohydrate recognition of some bioactive symmetrical tripodal receptor type tris(2-aminoethyl)amine (TAEA) derivatives was investigated. In calorimetric experiments, the highest binding constant ( Ka) of compound C (CHNOS) with methyl α- d-mannopyranoside was Ka = 858 M with 1:1 stoichiometry. Formation of hydrogen bonds in binding between symmetrical tripodal receptor type compound C and sugars was suggested by the large negative values of ∆ H° (=−34 to −511 kJ mol). In a comparison of each set of α- and β-anomers of some monosaccharides (methyl α/β- d-galactopyranoside, methyl α/β- d-glucopyranoside, and methyl α/β- l-fucopyranoside), compound C showed that the binding constant of β-anomer was larger than that of the corresponding α-anomer, indicating higher β-anomer selectivity. The calculated energy-minimized structure of the complex of compound C with guest methyl α- d-mannopyranoside is also presented. The experimental results obtained from this work indicated that symmetrical tripodal receptor type TAEA derivative C has a lectin-like carbohydrate recognition property. [ABSTRACT FROM AUTHOR]

Novel complexes of type MLCl· nHO (M: Ni, n = 4; M: Cu, n = 2.5 and M: Zn, n = 1.5; L: ligand resulted from 1,3-phenylenediamine, 3,6-diazaoctane-1,8-diamine, and formaldehyde one-pot condensation) were synthesized and characterized. The ligand was also isolated and characterized. The complexes features have been assigned from microanalytical, electrospray ionization tandem mass spectrometry, IR, UV-vis, H NMR, and EPR spectra as well as magnetic data at room temperature. Simultaneous thermogravimetric/dynamic scanning calorimetry/evolved gas analysis measurements were performed to evidence the nature of the gaseous products formed in each step. Processes as water elimination, fragmentation, and oxidative degradation of the organic ligand as well as chloride elimination were observed during the thermal decomposition. The final product of decomposition was metal(II) oxide except for copper complex where CuCl remained also in the oxide network. The complexes exhibited an improved antibacterial activity in comparison with the ligand concerning both planktonic as well as biofilm-embedded cells. [ABSTRACT FROM AUTHOR]

In order to develop new metallo-antimicrobials the complexes of type MLCl· nHO (( 1) M: Co, n = 0; ( 2) M: Ni, n = 2; ( 3) M: Cu, n = 2.5; ( 4) M: Zn, n = 0, HL: Schiff base derived from acetylacetone and 3-amino-4H-1,2,4-triazole) were synthesized by template condensation. The features of complexes have been assigned from microanalytical, IR and UV-Vis-NIR data. The species heating in air evidenced processes as melting, water and hydrochloride endothermic elimination as well as oxidative degradation of the Schiff base. The temperature ranges as well as modification in the electronic spectra of dehydrated intermediates indicate the presence of both coordination and crystallisation water molecules. The final product of decomposition was the most stable metal oxide as powder X-ray diffraction indicated. [ABSTRACT FROM AUTHOR]

Five new coordinative compounds that contain mixed ligands (4,4′-bipyridine and methacrylate anion) were synthesized and characterized (elemental analysis, IR and UV-Vis spectroscopy, and thermal studies). The complexes are of the type [M(4,4′-bipy)(CHO)]· nHO (( 1) M:Mn, n = 0; ( 2) Co, n = 0.5; ( 3) M:Ni, n = 1.5; ( 4) M:Cu, n = 0.5; ( 5) M:Zn, n = 0.5; 4,4′-bipy: 4,4′-bipyridine; CHO: methacrylate anion). All the tested complexes exhibited very low MIC values against Escherichia coli strains and one compound against Staphylococcus aureus. Besides the specific antimicrobial spectrum, these compounds also inhibited the microbial ability to colonize the inert surfaces, acting as potential anti-adherence and biofilm-controlling agents. The thermal behavior provided confirmation of the complexes' compositions as well as the number and the nature of water molecules and the intervals of thermal stability. [ABSTRACT FROM AUTHOR]

Starting from 5-bromo- N,N′-bis-(salicylidene)- o-tolidine (HL) new complexes with Co(II), Ni(II) and Cu(II) were synthesised and characterised. The features of complexes have been assigned from microanalytical, IR, UV-Vis-NIR and EPR spectra, magnetic data at room temperature as well as thermal analysis. IR data are in accordance with bischelate nature of the deprotonated ligand that coordinates through azomethinic nitrogen and phenolic oxygen. The electronic spectra display the characteristic pattern of tetrahedral stereochemistry for [CoL]·HO complex and octahedral one for [NiL(OH)]·HO complex. The electronic spectra correlated with magnetic susceptibility measurements indicate a square-planar surrounding for [ML] (M:Ni, Cu) species, while the EPR spectrum of copper complex sustains the proposed stereochemistry. The thermal analysis evidenced that thermal transformations are complex processes according to TG, DTA and DTG curves including (crystallization or coordination) water elimination, thermolyses and oxidative degradation of Schiff base. All these processes lead to the most stable metallic oxides as final product. [ABSTRACT FROM AUTHOR]

New complexes of type [M(HL)(CHCOO)(OH)]·nHO (where M:Co, m = 2, n = 2; M:Ni, m = 2, n = 1.5; M:Zn, m = 0, n = 2.5 and M:Cd, m = 0, n = 0; HL:5-bromo- N, N′-bis-(salicylidene)- o-tolidine) have been synthesized and characterized by microanalytical, IR, UV-Vis-NIR and magnetic data. Electronic spectra of Co(II) and Ni(II) complexes are characteristic for an octahedral stereochemistry. The IR spectra indicate a chelate coordination mode for mono-deprotonated Schiff base and a bidentate one for acetate ion. The thermal transformations are complex according to TG and DTA curves including dehydration, acetate decomposition and oxidative degradation of the Schiff base. The final product of decomposition is the most stable metallic oxide. [ABSTRACT FROM AUTHOR]

The reaction between [M(DMBG)2]· nH2O (( 1) M:Ni, n = 0; ( 4) M:Cu, n = 1), ammonia/hydrazine and formaldehyde in methanol resulted in new complexes of type [ML]· nH2O (( 2) M:Ni, L:L1, n = 0; ( 3) M:Ni, L:L2, n = 0, ( 5) M:Cu, L:L1, n = 0 and ( 6) M:Cu, L:L2, n = 3; HDMBG: N,N-dimethylbiguanide, L1 = ligand resulted from ammonia system and L2 = ligand resulted from hydrazine system). The features of complexes have been assigned from microanalytical, IR and UV–Vis data. The thermal transformations of compounds are complex processes according to TG and DTG curves including melting, phase transition, dehydration, oxidative condensation of –C=N– units as well as thermolysis processes. The final products of decomposition are the most stable metal oxides. [ABSTRACT FROM AUTHOR]

Four ethylenediamine-N,N,N′,N′-tetraacetate complexes with Sb(III)-M-Sb(III) polynuclear structure ( M=Co(II), La(III), Nd(III), Dy(III)) are synthesized. [Sb2-μ4-(EDTA)2Co(H2O)2]·5.15H2O is characterized by single crystal X-ray diffraction. The crystal structure of [Sb2-μ4-(EDTA)2Co(H2O)2]·5.15H2O belongs to monoclinic system, space group P21/n, lattice parameters: a=6.9969(2), b=20.8705(4), c=10.8106(2) Å, β=90.031(1)°, V=1578.66(6) Å3, Z=2, M r=1007.76, D c=2.120 g cm−3, F(000)=1001, μ=2.323 mm−1, the final R=0.0235 and wR=0.0629 for 3480 observed reflections (I>2σ(I)). The powder X-ray diffraction patterns of the complexes are also measured. Elemental analyses, FTIR spectra, TG-DSC and DTA of [Sb2(EDTA)2Ln]NO3·nH2O are performed. FTIR spectra reveal that the antimony and other metallic ions were connected through the carboxylate bridges. The thermal analysis can demonstrate the complex formation of the antimony, other metallic ions and EDTA. The possible pyrolysis reactions in the thermal decomposition process of the complexes, the experimental and calculated percentage mass losses are also given. [ABSTRACT FROM AUTHOR]

The viscoelasticity and thermal properties of aqueous solutions of blended xanthan gum (XA) with chitosan were investigated in order to study the electrostatic interaction established between two polysaccharides. Storage modulus G’, loss modulus G” and zero shear rate viscosity ηO attain a maximum at a chitosan concentration C max. The above results indicate that the junction between XA and chitosan is formed in a concentration range lower than C max and the viscoelasticity of systems increases with increasing concentration. In a concentration range higher than C max, junction formation may not occur effectively since the excess amount of chitosan completely screens anions of XA. The chain rigidity of XA decreases by the screening of the repulsive interaction between anions on XA chains. The ineffective junction formation and the decrease of XA chain rigidity may cause the decrease of viscoelasticity of systems with increasing concentration. The value of C max decreases with increasing molecular mass of chitosan. From melting enthalpy of the above system measured by DSC, the amount of non-freezing water ( W nf) was evaluated. W nf shows a minimum at the concentration C max. This fact suggests that hydrophobic fields increased by junction structure formation through ion-complexation between XA and chitosan molecules. [ABSTRACT FROM AUTHOR]

The reaction thermodynamic and kinetic equations for the non-reversible reactions are established. The enthalpy change of formation reaction of manganese(II) histidine (His) complex in water has been determined by microcalorimetry, using manganese chloride with L-a-histidine at 298.15-323.15 K. The standard enthalpy of formation of Mn(His)22+(aq) has been calculated. On the basis of experimental and calculated results, three thermodynamics parameters (the activation enthalpy, the activation entropy and the activation free energy), the rate constants, along with three kinetic parameters (the apparent activation energies, the pre-exponential constant and the reaction order) are obtained. The results show that the reaction easily takes place over the studied temperature range. The solid complex Mn(His)2Cl2·4H2O was prepared and characterized by IR and TG-DTG. [ABSTRACT FROM AUTHOR]

The hexakis(methylamine) complexes of nickel(II)-chloride, -bromide and -iodide have been prepared using-gas phase preparation procedure. The thermal decomposition starts with the release of four moles of the organic ligand. The bis(methylamine) intermediate decomposes in one step to the pure nickel(II) halide in the case of the chloride compound, however one and a half moles of methylamine containing intermediates were identified for the bromide and iodide analogues. The UV/VIS and the far IR spectra of the hexakis complexes show a typical octahedral environment around the central nickel(II) ion. [ABSTRACT FROM AUTHOR]