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Abstract Nanosized ZnO has been prepared following a non-polluting, straightforward, and flexible combustion synthesis method, using as biofuels starch and cellulose, and as zinc source nitrate and acetate. While the crystallite size and the surface area of the ZnO materials are to a certain extent sensible of the post-thermal processing temperature, the defect chemistry is dependent on reductant/oxidant ratio. The obtained ZnO materials, particularly the oxides obtained from carbohydrate-nitrate precursors present considerable photodegradation activity upon two hazardous EDCs phenolic wastes and excellent antimicrobial efficiency against planktonic Gram negative and positive strains. Both results can be explained by an optimum defects configuration of these oxides. The photocatalytic and biocidal efficiency associated with the easy and complete recovery from the treated wastewaters proves the potential toward environmental remediation applications of these "two in one" formulations. [ABSTRACT FROM AUTHOR]

The present work provides a new approach to the water denitration process and a facile strategy of catalyst preparation for the efficient hydrogen generation. The main focus of the research reported here was nitrate removal from aqueous solutions and simultaneous hydrogen generation under UV-Vis-light irradiation. This is a very important aspect in case of practical applications, eliminating the external source of hydrogen. Aiming to get a deeper understanding on the role of surface structures (size and shape of nanoparticles) towards the reduction mechanism and to establish basic principles for an efficient process, Pt-Cu/TiO 2 and Pt-Cu/TiO 2 modified with well-defined Pt nanoparticles were employed. The synthesized materials were characterized using various physicochemical techniques and tested comparatively for: (i) nitrate catalytic reduction by hydrogen (dark reaction) and (ii) nitrate photocatalytic reduction by in-situ generated solar hydrogen. In order to enhance overall denitration reaction by combined photocatalytic and catalytic processes, photo-generated charges and in-situ generated H 2 as reducing agent were used. Improvement of catalytic performances of nitrate hydrogenation reaction (~100% NO 3 ¯ conversion) related to intimate contact between Pt and Cu was obtained. The in-situ generated H 2 by water splitting over the studied catalysts reduces efficiently NO 3 ¯ ions. Enhanced photocatalytic activity toward solar H 2 production by deposited well-defined Pt nanoparticles (~10 nm) was achieved. In order to make possible decontamination of polluted waters using in-situ generated H 2 under light exposure, the future optimization of such photo-catalytic systems looks promising. [Display omitted] • Water denitration was carried out by combined photocatalytic and catalytic processes. • The in-situ generated solar H 2 by water splitting reduces efficiently nitrate ions. • Deposition of well-defined Pt Np's (~10 nm) onto Pt-Cu/TiO 2 enhances production of H 2. [ABSTRACT FROM AUTHOR]

Abstract: The crystal structures of two pentacyanido(L) ferrate(III) complexes, [P(C6H5)4]2[Fe(CN)5(prz)]·4H2O 1, [P(C6H5)4]2[Fe(CN)5(4,4′-bipy)]·3H2O 2, have been solved. Within the two complex anions the iron atoms are hexacoordinated by five cyanido ligands, the sixth position being occupied by the nitrogen atom arising from pyrazine and, respectively, 4,4′-bipyridine. The electrochemical properties of compounds 1, 2 and of the azido derivative, (Ph4As)2[Na(H2O)4][Fe(CN)5(N3)] 3, have been investigated by cyclic voltammetry. A relatively complicated redox behavior of these complexes was found, due especially to the electron transfer involving the central metallic ion that changes reversibly its oxidation state (FeIII/FeII redox site) and also to the coligand (4,4′-bipyridine, pyrazine or azide) which intervenes in a distinct electron transfer. The experimental data have been rationalized through DFT calculations. [Copyright &y& Elsevier]

Abstract: By employing the common precursor Na3[Fe(CN)5(NH3)]·3H2O in a new synthetic approach, the azidopentacyanoferrate(III) ion has been isolated and structurally characterized as (Ph4As)2[Na(H2O)4][Fe(CN)5(N3)] 1. In order to confirm its building block ability, compound 1 has been reacted with the mononuclear complex [Mn(valphen)(H2O)2]ClO4 (H2valphen represents the Schiff base resulting from the condensation of o-vanillin with 1,2-phenylenediamine in a 2:1M ratio) to afford the new MnIII–FeIII heterometallic system [Mn(valphen)(H2O)2]2[(H2O)(valphen)Mn(μ-CN)Fe(CN)4(N3)]·8H2O 2. The crystal structure of compound 2 reveals a supramolecular assembly generated by [(H2O)(valphen)Mn(μ-CN)Fe(CN)4(N3)]2− dianions and discrete [Mn(valphen)(H2O)2]+ counterions. The dynamic magnetic measurements of compound 2 point to a slow relaxation of the magnetization. [ABSTRACT FROM AUTHOR]

Abstract: A trinuclear copper(II) complex, [Cu3(2,5-pydc)2(Me5dien)2(BF4)2(H2O)2]·H2O 1, has been constructed from 2,5-pyridine-dicarboxylato bridges (2,5-pydc2−) and N,N,N′,N″,N″-pentamethyl-diethylenetriamine (Me5dien) acting as a blocking ligand. The copper ions, within the centrosymmetric trinuclear cations, are connected by two 2,5-pydc2− bridges, with an intramolecular Cu···Cu separation of 8.432Å. The central copper ion exhibits an elongated octahedral geometry, with semicoordinated ions, while the terminal ones are pentacoordinated (distorted square-pyramidal geometry). The cryomagnetic investigation of 1 reveals an antiferromagnetic coupling of the copper(II) ions (J =−5.9cm−1, H =−JS Cu1 S Cu2 − JS Cu2 S Cu1a). [Copyright &y& Elsevier]

Abstract: Four new coordination polymers were obtained by employing polycarboxylato spacers and cationic copper(II) complexes as nodes: ∞ 2[Cu3(trim)2(NH3)6(H2O)3] (1); ∞ 1[Cu(tmen)(dhtp)] (2), ∞ 1[Cu(tmen)(hitp)(H2O)] (3), ∞ 1[Cu(tmen)(nitp)] (4). (H3trim=trimesic acid, H2dhtp=2,5-dihydroxy-terephthalic acid; H2hitp=5-hydroxy-isophthalic acid, H2nitp=5-nitro-isophthalic acid; tmen= N,N,N′,N′-tetramethyl-ethylenediamine). The crystal structures of the four compounds have been solved. Compound 1 consists of 2D coordination polymers with heart-shaped meshes, while compounds 2–4 contain infinite zigzag chains. The role of the hydrogen bond interactions in sustaining the supramolecular solid-state architectures in compounds 1 and 3 is discussed. The cryomagnetic investigation of compounds 1, 2, and 4 reveals antiferromagnetic interactions between the copper ions. [Copyright &y& Elsevier]

Abstract: We present a symbolic decision procedure for time-sensitive cryptographic protocols. We consider protocols described in a process algebra-like notation that includes clocks, time-stamps and time variables. While the values of all clocks increase with rate one when time passes, time variables are simply variables that range over the time domain and can be used to remember time-stamps, i.e. time values. Our symbolic decision procedure deals with secrecy, authentication and any property that can be described as a safety property. Our approach is based on a logic representation of sets of configurations that combines a decidable logic with time constraints. [Copyright &y& Elsevier]