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We report a facile one-pot solution phase synthesis of one-dimensional Ge1−x Sn x nanowires. These nanowires were synthesized in situ via a solution-liquid-solid (SLS) approach in which triphenylchlorogermane was reduced by sodium borohydride in the presence of tin nanoparticle seeds. Straight Ge1−x Sn x nanowires were obtained with an average diameter of 60 ± 20 nm and an approximate aspect ratio of 100. Energy-dispersive x-ray spectroscopy (EDX) and powder x-ray diffraction (PXRD) analysis revealed that tin was homogeneously incorporated within the germanium lattices at levels up to 10 at%, resulting in a measured lattice constant of 0.5742 nm. The crystal structure and growth orientation of the nanowires were investigated using high-resolution transmission electron microscopy (HRTEM). The nanowires adopted a face-centred-cubic structure with individual wires exhibiting growth along either the 〈111〉, 〈110〉 or 〈112〉 directions, in common with other group IV nanowires. Growth in the 〈112〉 direction was found to be accompanied by longitudinal planar twin defects.

A convenient method for the preparation of transparent, photocatalytic titania thin films is described. The films do not require annealing or thermal processing to develop photoactivity, thus can be applied to many thermally-sensitive substrates. Oxalic acid is used in place of the usual mineral acids to peptize the precipitated hydrous titania formed from the hydrolysis of titanium iso- propoxide. This leaves no inorganic residues in the film resulting in a higher quality film. The mineral phase and the photocatalytic activity produced are strongly influenced by the ratio of oxalic acid:titanium iso- propoxide employed. The peptization is carried out at 65 °C with vigorous stirring for 1 h in water containing 15% v/v ethanol, followed by a hydrothermal step at 95 °C. High oxalic acid:Ti molar ratios (0.5:1) result in rutile free sols, while lower ratios (0.25:1) result in anatase, rutile, brookite and TiO 2 (B) in varying proportions. The films were exposed to low level UV light to cure, and photodecompose the residual organic components in the film. The photodecomposition of residual oxalic acid in the cast films were monitored using infrared spectroscopy. Photo-activity of the UV-cured films was compared by monitoring the decoloration of methylene blue stains on the film, by UV–Vis spectroscopy. Transmission was greater than 99% across the visible light region (400–800 nm).

Environmental risk assessment of nanomaterials requires information not only on their toxicity to non-target organisms, but also on their potential exposure pathways. Here we report on the transport and fate of quantum dots (QDs) in the total environment: from soils, through their uptake into plants, to their passage through insects following ingestion. Our QDs are nanoparticles with an average particle size of 6.5 nm. Breakthrough curves obtained with CdTe/mercaptopropionic acid QDs applied to columns of top soil from a New Zealand organic apple orchard, a Hastings silt loam, showed there to be preferential flow through the soil's macropores. Yet the effluent recovery of QDs was just 60%, even after several pore volumes, indicating that about 40% of the influent QDs were filtered and retained by the soil column via some unknown exchange/adsorption/sequestration mechanism. Glycine-, mercaptosuccinic acid-, cysteine-, and amine-conjugated CdSe/ZnS QDs were visibly transported to a limited extent in the vasculature of ryegrass (Lolium perenne), onion (Allium cepa) and chrysanthemum (Chrysanthemum sp.) plants when cut stems were placed in aqueous QD solutions. However, they were not seen to be taken up at all by rooted whole plants of ryegrass, onion, or Arabidopsis thaliana placed in these solutions. Leafroller (Lepidoptera: Tortricidae) larvae fed with these QDs for two or four days, showed fluorescence along the entire gut, in their frass (larval feces), and, at a lower intensity, in their haemolymph. Fluorescent QDs were also observed and elevated cadmium levels detected inside the bodies of adult moths that had been fed QDs as larvae. These results suggest that exposure scenarios for QDs in the total environment could be quite complex and variable in each environmental domain.

The preparation of ligand-functionalised copper(II) hydroxide (Cu(OH)(2)) particles and their conjugation with hydrophobic CdSeS quantum dots (QDs) is reported. The photoluminescence of the QDs is efficiently quenched upon their conjugation with the functionalised Cu(OH)(2) particles. Cu(OH)(2) was functionalised with 2,2'-dipyridyl (2,2-bipy) and n-octanoic acid (OcA), by adsorption of the desired ligand to Cu(OH)(2) suspended in solvent. The resulting functionalised Cu(OH)(2) substrates were characterised using infrared, UV-visible diffuse reflectance, and X-ray photoelectron spectroscopic techniques, TEM imaging, and micro- and thermogravimetric analysis. The spectral data indicated that both 2,2-bipy and OcA coordinated to Cu(OH)(2) in a bidentate manner. The functionalised Cu(OH)(2) substrates were introduced to suspensions of hydrophobic CdSeS QDs, and the resulting QD-functionalised Cu(OH)(2) conjugates were also characterised using spectroscopic and electron microscopy techniques. UV-visible diffuse reflectance spectroscopy indicated the extension of the optical absorption of the Cu(OH)(2) to longer wavelengths upon conjugate formation.

Aqueous titanium citrate solutions were prepared from the reaction of citric acid with titanium 2-propoxide in a range of molar ratios. Solutions containing two or fewer citrates per titanium resulted in the slow crystallization of an insoluble titanium oxo-citrate complex. Single-crystal X-ray analysis identified the species as Ti(8)O(10)(citrate)(4)(H(2)O)(12).14H(2)O.3HOPr(i)(), crystallized in the tetragonal space group I4(1)/a, with a = 30.775(7) A, c = 14.528(7) A, V = 13 759(8) A(3), and Z = 8. The trianionic citrate ligands supply both carboxylate and alkoxide coordination and stabilize the structure using simultaneous chelating and bridging modes of attachment. The compound is a neutral species, exhibiting titanium in three contrasting environments. Laser Raman microscopy and (13)C CPMAS solid-state NMR data were consistent with those of the X-ray crystal structure. When exposed to air, the crystals rapidly lost water and became a powder. The dehydrated powder was noncrystalline to X-rays and insoluble, but (13)C NMR results demonstrated retention of the carboxylate linkages.

A family of triethanolamine complexes of titanium with varying metal/ligand ratios have been prepared from reactions of titanium tetraisopropoxide with triethanolamine. Three nonhydrolytic products, having essentially all isopropoxide ligands substituted by triethanolamine, were prepared as hygroscopic, glassy solids. Crystals of two hexameric titanatrane partial hydrolysis analogues [Ti3(mu 2-O)((HOCH2CH2)2NCH2CH2O)(OCH2CH2)2(mu 2-OCH2CH2)N)2(OCH2CH2)(mu 2- OCH2CH2)2N)]2 (1), and [Ti3(mu 2-O)(OCH(CH3)2)((OCH2CH2)2(mu 2-OCH2CH2)N)2(OCH2CH2)(mu 2- OCH2CH2)2N)]2 (2) were isolated and structurally characterized. The structures consist of a central core of two oxo-bridged dititanatranes (TEA)TiOTi(TEA) (TEAH3 = triethanolamine) with the nonhydrolytic residue (TEA)Ti(TEAH2) included as an adduct in (1), analogously to (TEA)Ti(OPri) in (2).

TiO2 (anatase)-based photocatalyst powders containing up to 20 mol% calcium, strontium or barium ions were prepared from α-titanic acid by calcining gels prepared from triethanolamine-based sols at 600°C. The powders were characterised using X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance ultraviolet spectrophotometry, nitrogen sorption porosimetry and in situ infrared spectroscopy to examine surface adsorbed species. Compositions containing greater than 15 mol% alkaline earth ions resulted in largely amorphous materials. The residual anatase showed decreased crystallite sizes and increased crystallographic cell volumes with increasing concentration of alkaline earth ions, while the BET surface areas of the materials increased from around 80 m2 g−1 (no additive) to 160 m2 g−1 at higher levels of additive. Electronic spectroscopy showed that the band gaps of the materials increased with increasing Ca2+ content, due to the decreasing particle sizes. Under the synthesis conditions used, no other crystalline phase was observed, except rutile (

The three independent mol­ecules in a single crystal of the tricyclic compound 15-[3-(dimethyl­amino)prop­oxy]-5,5,13,13-tetra­methyl-1,7,9,14,16-penta­oxa-5,13-diazo­nia-15-bora-6,8-di­borata­dispiro­[5.1.5.3]hexa­decane, C15H36B3N3O6, are bound in dense layers by C—H⋯O(B) inter­molecular inter­actions. The 3-(dimethyl­amino)propoxy arms adopt three different conformations with only van der Waals contact distances between the layers. The replicated differences in the B—N bond lengths [mean 1.723 (7) and 1.678 (5) A] for equivalent geometries are addressed using density functional theory (DFT) calculations.

The centrosymmetric tetranuclear title compound, bis­(methyl­imino­diethano­lato)­dodecapropanolatodititaniumdizirconium, [Ti2Zr2(C3H7O)12(C5H11NO2)2], has a zigzag TiZr2Ti arrangement including novel triple-oxo Ti⋯Zr bridges. The methyl­imino­diethano­late ligand is bound to the zirconium in a meridional configuration, with the ethano­late O atoms bridging both the Ti⋯Zr and Zr⋯Zr centres. Two n-propanolate O atoms provide the other two Ti⋯Zr bridges. The remaining propanolate ligands are attached to either Zr or Ti, completing seven- and six-coordination, respectively. The distorted pentagonal bypyramidal [ZrO5N2] units edge-share with each other and face-share with the distorted octahedral [TiO6] units. As well as some conventional conformational disorder involving alternative carbon-chain conformations, there is some iso- and n-propanolate chemical disorder around the Ti atoms.

The centrosymmetric tetrameric title compound, bis­(methyl­imino­diethano­lato-κ5O:O,N,O′:O′)­tetra-μ-n-propanolato-κ8O:O-octa-n-propanolato-κO-tetrazirconium, [Zr4(C5H11NO2)2(C3H7O)12], contains eight μ2-O-atom Zr—O—Zr bridges. Each methyl­imino­diethano­late ligand is bound to one of the two central Zr atoms with a Zr—N distance of 2.412 (5) A in a meridional configuration(s), with the ethano­late O atoms bridging both the central Zr atoms. Four n-propanolate ligands provide O atoms to bridge other pairs of Zr atoms. The remaining propanolate ligands bind terminally to one metal atom each, to make up 7- and 6-coordination for the the central and outer Zr atoms, respectively. The distorted ZrO6 octahedra each share a face with one of the central ZrO6N pentagonal bipyramids; these edge-share with each other across the centre of symmetry.

The thermal stability of some new organotellurium compounds containing an acetamido group in the ortho -position to the tellurium atom (i.e. Ar2Te, ArAr'Te and Ar2Te2, where Ar' is 2-(CH3CONH)-5-R-C6H3, R is CH3, Br, NO2; Ar' is 2-(CH3CONH)-5-R'-C6H3, and R' is Br, NO2 have been studied by thermogravimetric analysis. In general, these compounds extruded tellurium in addition to one or two acetamido groups in one or two steps.

A range of novel organotellurium compounds with an amino group ortho to the tellurium atom (i.e. ArTeBr3 and Ar2Te, where Ar = 2-NH2-5-RC6H3; R = CH3, Br, NO2) have been prepared by a convenient new route involving reaction of the corresponding 2-aminoarylmercury chloride with tellurium tetrabromide. Reduction of ArTeBr3 gave the compounds Ar2Te2 in good yield; these were treated with chlorine to give ArTeCl3 in quantitive yield.

A range of novel organotellurium compounds with an amino group ortho to the tellurium atom (i.e. ArTeBr3 and Ar2Te, where Ar = 2-NH2-5-RC6H3; R = CH3, Br, NO2) have been prepared by a convenient new route involving reaction of the corresponding 2-aminoarylmercury chloride with tellurium tetrabromide. Reduction of ArTeBr3 gave the compounds Ar2Te2 in good yield; these were treated with chlorine to give ArTeCl3 in quantitive yield.

Ti6O6(MDEA)6·2CH2Cl2 (MDEA = N-methyldiethoxoamine) was obtained by the controlled hydrolysis of the Ti(MDEA)2 complex and analysed by X-ray diffraction. The compound consists of a ring of six [TiO5N] octahedra, edge bridged by μ2-oxide and a μ2-alkoxide arm of the aminoalkoxide ligand.

International audience; The synthesis of several new bismuth porphyrin complexes Bi(por)(X) containing the tpp or tpClpp (tpClpp = 5,10,15,20-tetra-chlorophenylporphyrin) porphyrin ligand and anions X = NO3, Cl, Br, I are described. Molecular structures reported for Bi(tpClpp)(X) for X = Cl, Br show that the complexes crystallise as centrosymmetric dimers doubly bridged through Cl or Br. Bi(tpClpp)(NO3) crystallises as a less symmetric dimer in which one NO3 ligand bridges the two bismuth centres and the second NO3 ligand interacts with only one bismuth atom. In all three structures the bismuth atoms are significantly displaced from the porphyrin N4 planes and the Bi–halide or Bi–O distances are very long.

The title compound, octa-tert-butoxybis[micro(3)-2,2'-(N-methylimino)diethanolato]di-micro-oxo-tetratitanium(IV), [Ti(2)O[(OCH(2)CH(2))(2)(NCH(3))][(CH(3))(3)CO](4)](2) or [Ti(4)(C(5)H(11)NO(2))(2)(C(4)H(9)O)(8)O(2)], lies about an inversion centre, and displays the less usual zigzag configuration. One O atom of the N-methyldiethoxoamine ligand bridges the symmetry-related Ti atoms, while the other bridges the two independent Ti atoms, with the N atom binding to give a facial configuration. Four (t)BuO(-) ligands and a bridging oxide complete the respective five- and sixfold coordination of the two Ti atoms. The Ti-O bond lengths range in a self-consistent fashion from 1.7624 (17) to 2.0878 (18) A, while the Ti-N bond length is 2.374 (2) A.

A highly fluxional dititanium N-methyldiethoxoamine hexaisopropoxide complex was isolated from reactions of N-methyldiethanolamine with Ti(OPri)4. X-ray crystallography identified the solid state compound as the unsymmetrical complex Ti2(μ2-(OCH2CH2)2NCH3)(μ2-OPri)(OPri)5. In solution, the time-averaged structure was shown by NMR to be symmetrical. The amine function coordinates to both titanium atoms alternately, while the isopropoxide ligands exchange to maintain equal coordination numbers on both titaniums. Variable temperature NMR demonstrates that the exchange processes slow on cooling, and a spectrum consistent with the solid-state structure is apparent at –50�C.

A method for producing amino alcohol complexes of titanium from hydrated titania (α-titanic acid) is described. Thus hydrated titania was completely converted into triethanolamine and diethanolamine complexes during reaction at 120°C for 6 h. This represents a synthetic method for titanium sol–gel precursors which are free from chlorine-containing impurities. Products were characterized with assistance from 1 H and 13 C nuclear magnetic resonance spectroscopy, and electrospray mass spectrometry. A single-crystal X-ray structure of titanium bis[2,2´- (methyl-imino)ethanolate], tetragonal, space group P4 – 2 1 c, is presented. The titanium centre is coordinated by an N2O4 donor set which can be most closely described as a bifacially capped tetrahedral geometry.

Titanium and its alloys are widely used in the aeronautical and chemical industries. This paper reports on an experimental investigation into the effect of boronising on wear behaviour in dry sliding. Boronising eliminates running-in wear, reduces oxidative (mild) wear, and increases the load at which transition to metallic (severe) wear occurs. The boronised layer has a considerable life, which is inversely related to applied load, and the surfaces remain protected even after the layer has been completely removed

The nature of the oxide on the surface of titanium and the Ti-6Al-4 V alloy after a number of recommended treatments has been examined by x-ray and electron diffraction. No evidence for material other than titania in its rutile form was obtained even though anatase and fluoride have been reported. The most efficient surface for adhesive bonding is a rough surface of the black oxide such as is produced by treatment of the metal in alkaline hydrogen peroxide.

The surface preparation of stainless steel of identified martensitic structure has been studied in relation to the strength of adhesive bond with an epoxy-phenoiic, an epoxy and a polyimide adhesive. Attention has been given to replacing the inefficient mechanical removal of deposited carbon (“smut”) by chemical means. Seven different chemical treatments by acids or acid combinations were tried. Hydrofluoric or sulphuric acids modified by nitric or oxalic acids respectively were most satisfactory followed by chromic acid desmutting.

Complexes of the ligands 1,6-bis-2-butyltellurophenyl-2,5-diazahexa-1,5-diene (I) and 1,4-bis-2-butyltellurophenyl-2,3-diazabuta-1,3-diene (II) with palladium, platinum, and rhodium are described. [PdCl(I)(H2O)]Cl is an electrolyte and has the chloro-ligand trans to water; the implications for the mode of coordination of I are discussed. For [PdCl2(II)] evidence for both “cis” and “trans” isomers is obtained; since, as in the above case, no evidence for N-coordination is obtained, the nature of the “trans” isomer is debated. [PtCl(I)(H2O)]Cl, an electrolyte, decomposes in polar solvents to give [PtCl2(I2−)], where (I2−) donotes ligand I which has lost two butyl groups, the complex being a platinum(IV) derivative. Ligand I coordinates only via tellurium in the platinum(II) complex, but some evidence of N-coordination to platinum(IV) is obtained. The early stages of the de-alkylation reaction are monitored by 125Te and 195Pt NMR spectroscopy. By contrast, [PtCl2(II)] · H2O is a cis complex in which II coordinates via tellurium only and does not undergo de-alkylation. Some complexes of both rhodium(III) and rhodium(I) are reported. The most interesting observation being that I may function as a terdentate ligand (Te, N, Te) in [RhCl(I)].

The synthesis and molecular structure of bis(2-(2-pyridyl)phenyl)tritelluride are described. There is a short Te⋯N non-bonded interaction of 2.554(7) A, which may be responsible for the stability of the molecule. The tritelluride can be converted into the related ditelluride by treatment with copper in refluxing dioxane. The ditelluride may also be prepared by a route not involving the tritelluride.

The structure of 1,6-bis-2-butyltellurophenyl-2,5-diazahexa-1,5-diene (1) reveals a weak tellurium–nitrogen interaction giving the tellurium atom an effective co-ordination number of 3; with HgCl2, (1) forms the complex [HgCl2·(1)] which is monomeric with four-co-ordinate mercury(II) bonded to two chlorine and two tellurium atoms, (1) thus forming a 13-membered chelate ring.

The synthesis of 1,6-bis(2-butyltellurophenyl)-2,5-diazahexa-1,5-diene and related compounds is reported. Reaction with halogenating reagents leads to rupture of the Te–Bu bond and the isolation of new organyltellurium mono- and tri-halides stabilised via co-ordination to the imino-nitrogen atom. Reduction of the trihalides with sodium metabisulphite stops at the monohalide stage and no ditelluride is produced. Reduction of the tri- or mono-halides with hydrazine hydrate gives, depending on the molar ratio of reactants, either N-amino or N-hydroxo-compounds and in this case ditellurides are formed. Reduction of the trihalides with NaBH4 affords a poly- or oligo-merit tritelluride stabilised by co-ordination of tellurium with the imino-nitrogen atom. By contrast the reaction of 2-(butyltelluro) benzaldehyde with chlorinating agents gives 2-(butyldichloro-telluro) benzaldehyde in which the Te–Bu linkage survives intact. Spectroscopic data, particularly 13C n.m.r., are presented and briefly discussed. The crystal and molecular structures of bis[2-(hydroxyiminomethyl)phenyl] ditelluride and of 2-(butyldichlorotelluro) benzaldehyde have been determined. The ditelluride has Te–Te 2.746(1)A with C–Te–Te angles of 100.0(2) and 100.3(2)°; Te–N distances of 2.822(5)A and 2.876(5)A indicate a weak interaction. In the benzaldehyde derivative the tellurium is bonded to two carbon atoms and two chlorine atoms; a weak Te ⋯ O interaction [2.839(4)A(mean for two independent molecules)] and a lone pair of electrons complete a distorted pseudo-octahedral co-ordination. The molecule, apart from the two axial chlorine atoms, is essentially planar.

A pin-on-disc technique has been used to investigate the adhesive wear (galling) characteristics of C.P. Ti and I.M.I.318 under dry sliding conditions. Both materials exhibit running-in before equilibrium wear is established and also show mild/severe transitional behaviour. The wear characteristics of I.M.I.318 are considerably superior to C.P. Ti. Boronising, which is a surface diffusion process, produces titanium borides which inhibit adhesive wear and prevent metal transfer from the pin to the disc surface. The load-bearing capacity of both materials is considerably increased by boronising.

The structure of 1,6-bis-2-butyltellurophenyl-2,5-diazahexa-1,5-diene (1) reveals a weak tellurium–nitrogen interaction giving the tellurium atom an effective co-ordination number of 3; with HgCl2, (1) forms the complex [HgCl2·(1)] which is monomeric with four-co-ordinate mercury(II) bonded to two chlorine and two tellurium atoms, (1) thus forming a 13-membered chelate ring.