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Two new mononuclear complexes, [Cu2Cl1.23(NO3)0.77(Ampy)4(H2O)4](NO3)2·4H2O (I) and [CdI2(Ampy)2] (II) (Ampy = 4-amino-6-methoxypyrimidine) have been synthesized and characterized by single crystal X-ray diffraction studies (CCDC nos. 2023331 (I), 2023331 (II)) at 295 K for (I) and 100 K for (II). The structure of the Cu(II) complex shows that the Cu(II) central atom is five-coordinated with a distorted square pyramidal geometry. In compound (II) the Cd(II) cations are tetracoordinated with a distorted tetrahedral fashion. Intermolecular interactions were investigated by Hirshfeld surfaces. Electronic properties such as HOMO and LUMO energies were derived. [ABSTRACT FROM AUTHOR]

(C6H18N3)4[CuCl5]2[CuCl4]3·1.42H2O is prepared and characterized by various physicochemical techniques. The single crystal X-ray diffraction structural analysis reveals that the title compound belongs to the orthorhombic system with the space group Cmca. Its unit cell dimensions are: a = 24.286(2) Å, b = 14.3082(14) Å, c = 16.6160(16) Å, Z = 4, V = 5773.8(10) Å3. Its crystal structure is determined and refined down to R = 0.024 and wR(F2) = 0.059. The structure contains three crystallographically independent Cu2+ ions coordinated to chlorine anions in various fashions. Cu1 is five-coordinated in a distorted square pyramidal fashion, while Cu2 and Cu3 are four-coordinated in square planar and distorted tetrahedral fashions, respectively. The entities are interconnected by means of the hydrogen bonding [O(W)-H...Cl, N-H...Cl, C-H...Cl and C-H...O(W)], forming a three-dimensional network. Intermolecular interactions are investigated by Hirshfeld surfaces and the contacts of the eight different chloride atoms are notably compared. The vibrational absorption bands are identified by infrared spectroscopy. The optical study is performed by UV-vis absorption. [ABSTRACT FROM AUTHOR]

The chemical preparation and characterization of a novel coordination compound [CuClO4(C4H6N2O)4H2O]ClO4(C4H6N2O)0.08 is reported. The compound crystallizes in the monoclinic space group P21/c with lattice parameters a = 11.2678(5) Å, b = 12.8102(6) Å, c = 19.7250(8) Å, β = 100.3051(15)°, V = 2801.2(2) Å3. The Cu(II) cation is six-coordinated in an elongated distorted octahedral fashion by four N atoms of four 3-amino-5-methylisoxazole ligands, one water oxygen atom, and one perchlorate oxygen atom. In the atomic arrangement, the coordinated and uncoordinated perchlorate anions are grouped in pairs to form anionic layers parallel to the (a, b) plane. A substantial number of H-bonding interactions leads to the formation of an intricate three-dimensional network. The vibrational absorption bands are identified by infrared spectroscopy and the electrical properties are studied by impedance spectroscopy. The DSC analysis agrees with the electrical conductivity results. Magnetic properties are also determined to characterize the complex. [ABSTRACT FROM AUTHOR]

The physicochemical properties of a new cyclohexaphosphate, (CHN)(HO)(PO), prepared by an acid-base reaction between cyclohexaphosphoric acid HPO and 2,4,6-trimethylaniline, are discussed on the basis of X-ray crystal structure investigation. The crystal structure determination reveals that the complete cyclohexaphosphate anion, with chair conformation, is generated by crystallographic inversion symmetry. The asymmetric unit consists of two organic cations, one half-anion and one hydronium cation. The atomic arrangement can be described by thick layers built by PO anions and HO cations parallel to the (a, b) plane. Each cyclohexaphosphate group is connected to its adjacent neighbors by six hydronium ions through strong O-H...O hydrogen bonds. The protonated amines are located between these successive inorganic layers, in order to balance the negative charge of the inorganic framework by establishing N-H...O hydrogen bonds with the O atoms of the PO anions. The three-dimensional cohesion is assured by different interactions (electrostatic, H-bonds, van der Waals) established between the various molecular components. This compound is also characterized by infrared spectroscopy and solid state MAS-NMR. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The synthesis and physico-chemical characterization of a novel organic-inorganic hybrid material, 1-(2,5-dimethylphenyl)piperazine-1,4-dium tetrachloridocuprate(II), have been reported. This compound crystallizes in the monoclinic system with the space group of P2/ n and cell parameters a = 9.833(3), b = 16.337(2), c = 10.452(3) Å, β = 102.13(4), Z = 4 and V = 1641.5(7) Å . In the title salt, (CHN)[CuCl], the geometry of the CuCl $_{4}^{\mathrm {~2-}}$ ion is intermediate between tetrahedral and square planar. In the atomic arrangement tetrachlorocuprate anions and the piperazine-1,4-dium cations are held together via N-H ...Cl and C-H ...Cl to give a 1-D hybrid chain running along the a-axis. The six-membered piperazinedium ring adopts a chair conformation. The vibrational absorption bands were identified by infrared spectroscopy. Magnetic measurements reveal that moderate antiferromagnetic (AF) Cu-Cu interactions dominate in the title compound. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The synthesis and the structures of two new compounds with the general formula [CHNO]BiX·2HO (X = Br, Cl) are reported. They crystallize in the triclinic system and are isostructural. Crystal structures were solved and refined to R = 0.064, 0.048 and R = 0.15, 0.13 using 3392, 3679 independent reflections for the Cl and Br derivatives, respectively. The atomic arrangement can be described by inorganic chains along the [100] direction. These chains are themselves interconnected by means of N-H···X (X = Cl, Br) originating from the [CHNO] entities, to form three-dimensional network. The organic part consists of one organic cation which orients its two amine groups to the neighboring anions. The inorganic entity is made up of [BiX] dimers composed of two equivalent irregular octahedra sharing one edge. The oxygen atoms of the water molecules (OW) act as donor (O-H···X) and acceptor (N-H···O) of hydrogen bonds. The nature of the distortion of the inorganic polyhedra can be attributed to the stereoactivity of the Bi(III) lone electron pair. Raman and infrared spectra at room temperature were recorded in the 500-100 and 4000-400 cm frequency regions, respectively. This study confirms the presence of the organic cation [CHO] and the bioctahedron [BiX]. The calorimetric study shows that the title compound is stable until 384 K. [ABSTRACT FROM AUTHOR]

Organic-inorganic hybrid single crystals of [2,3-(CH)CHNH]BiBrNO.2HO were obtained by slow evaporation at room temperature and characterized by X-ray diffraction, IR and solid state NMR. This compound crystallizes in orthorhombic non-centrosymmetric space group Pca2 with the following lattice parameters: a = 25.8217(1), b = 7.8909(2), c = 21.4328(3) Å, V = 4367.07(13) Å and Z = 4. The structure was refined to R = 0.057 for 7069 independent reflections. The crystal is built up of 2,3-dimethylanilinium cations, [BiBr], disordered [NO] anions and water molecules. The crystal packing is governed by a three-dimensional network of O-H...O, N-H...O and N-H...Br hydrogen bonds and van der Waals interaction. The infrared spectrum has been interpreted on the basis of literature data. Solid state C CP-MAS-NMR spectrum is in agreement with the X-ray structure. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Photocatalytic reduction of two textile azo dyes, Naphthol Blue Black (NBB) and Disperse Blue 79 (DB79) has been carried out in colloidal WO3 and TiO2 suspensions. Under bandgap excitation of the semiconductor colloids these dyes undergo irreversible reduction as they react with the trapped electrons. The quantum efficiency for the photocatalytic reduction of these dyes were 5.4% and 4.8% for NBB and DB79 respectively. The kinetics and mechanism of the interfacial charge transfer in these colloidal suspension has been elucidated with transient absorption spectroscopy. The reaction between the dye and trapped electrons is diffusion limited and occurs with rate constants of 1.1×108 M−1s−1 and 4.0×107 M−1s−1 for NBB and DB79 respectively. [ABSTRACT FROM AUTHOR]

Ginkgo biloba extract is known to be efficient in diseases associated with free radical generation. The purpose of this work was to study, under in vitro conditions, the action of Ginkgo biloba extract (Gbe) against superoxide anion ( $$O_{2^{\bar .} }$$ ), which is directly or indirectly implicated in cell damage. Gbe appears to have both an $$O_{2^{\bar .} }$$ scavenging effect and also a superoxide dismutase activity. Its antiradical effect was demonstrated by low temperature electron spin resonance and in a non-enzymatic system (phenazine methosulfate-NADH), and its enzymatic activity was shown by polarographic determination. [ABSTRACT FROM AUTHOR]

The new organic cyclohexaphosphate (C6H7ClFN)4 (Li)2(P6O18)(H2O)4, has been synthesized at room temperature by an acid/base reaction between H6P6O18 and 3-chloro-4-fluoroaniline as an organic template. The crystal structure of (C6H7ClFN)4 (Li)2(P6O18)(H2O)4 was solved by single crystal X-ray diffraction analysis. A double head-to-head layer of cations is formed by hydrophobic interactions. Hirshfeld surface analysis reveals the nature of intermolecular contacts of the title compound. The contacts enrichment ratio shows that both strong electrostatic interactions and hydrophobic contacts are overrepresented. This hybrid material was then characterized by 1H, 13C, 31P, 15N and 19F solid-state NMR and IR spectroscopies. Electrical conductivity was also studied using impedance spectroscopy and results showed that the conductivity at 105 °C was equal to 96.5 × 10−4 S.cm−1. Antioxidant properties of this compound were studied, in vitro, at various concentrations with different tests; 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing power (FRAP), Trolox equivalent antioxidant capacity (TEAC) or ABTS+, using 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) as control. [ABSTRACT FROM AUTHOR]

The chemical preparation and characterization of a novel coordination compound [CuClO4(C4H6N2O)4H2O]ClO4(C4H6N2O)0.08 is reported. The compound crystallizes in the monoclinic space group P21/c with lattice parameters a = 11.2678(5) Å, b = 12.8102(6) Å, c = 19.7250(8) Å, β = 100.3051(15)°, V = 2801.2(2) Å3. The Cu(II) cation is six-coordinated in an elongated distorted octahedral fashion by four N atoms of four 3-amino-5-methylisoxazole ligands, one water oxygen atom, and one perchlorate oxygen atom. In the atomic arrangement, the coordinated and uncoordinated perchlorate anions are grouped in pairs to form anionic layers parallel to the (a, b) plane. A substantial number of H-bonding interactions leads to the formation of an intricate three-dimensional network. The vibrational absorption bands are identified by infrared spectroscopy and the electrical properties are studied by impedance spectroscopy. The DSC analysis agrees with the electrical conductivity results. Magnetic properties are also determined to characterize the complex. [ABSTRACT FROM AUTHOR]