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Water splitting by photocatalysis, for example employing seawater or wastewater, has the potential to make a substantial contribution to a future hydrogen economy. New types of 3D metal-wire substrates in woven form or brushes for photoelectrochemical processes are desirable to replace flat semiconductor-coated surfaces. In this report, titanium microwires (100 m diameter; pre-passivated) are employed to produce high surface area photoanodes with a TiO2 (rutile) nanocrystal array coating that was grown hydrothermally. A photo-active electrode is obtained with nanocrystal TiO2 rods of adjustable length from 1.67 µm up to 7.38 µm. Saturation of the photoelectrochemical response occurs at an intermediate length of approx. 3.19 µm with a photocurrent density of approximately 4.4 mA cm-2 at 1.0 V vs. Ag/AgCl (3M) in aqueous 1 M Na2SO4 under 100 mW cm-2 385 nm LED illumination. The effectiveness of vacuum annealing for enhancing TiO2 photochemical processes is demonstrated. The formation of oxygen in aqueous 1 M Na2SO4 electrolyte media (with/without chloride) is assessed using Clark probe measurements. Co-evolution of chlorine was evident in 1 M KCl. This work demonstrates that microwire photoelectrodes for woven form or brush structures are entirely feasible, and that pre-passivated titanium metal can be readily coated with titania nanocrystals via hydrothermal synthesis.

Six different thin film solar cells consisting of either orthorhombic (α-SnS) or cubic (π-SnS) tin(II) sulfide absorber layers have been fabricated, characterized and evaluated. Absorber layers of either π-SnS or α-SnS were selectively deposited by temperature controlled Aerosol Assisted Chemical Vapor Deposition (AA-CVD) from a single source precursor. α-SnS and π-SnS layers were grown on molybdenum (Mo), Fluorine-doped Tin Oxide (FTO), and FTO coated with a thin amorphous-TiOx layer (am-TiOx-FTO), which were shown to have significant impact on the growth rate and morphology of the as deposited thin films. Phase pure α-SnS and π-SnS thin films were characterized by X-ray diffraction analysis (XRD) and Raman spectroscopy (514.5 nm). Furthermore, a series of PV devices with an active area of 0.1 cm2 were subsequently fabricated using a CdS buffer layer, intrinsic ZnO (i-ZnO) as an insulator and Indium Tin Oxide (ITO) as a top contact. The highest solar conversion efficiency for the devices consisting of the α-SnS polymorph was achieved with Mo (η = 0.82%) or FTO (η = 0.88%) as the back contacts, with respective open-circuit voltages (Voc) of 0.135 and 0.144 V, and short-circuit current densities (Jsc) of 12.96 and 12.78 mA cm−2. For the devices containing the π-SnS polymorph, the highest efficiencies were obtained with the am-TiOx-FTO (η = 0.41%) back contact, with a Voc of 0.135 V, and Jsc of 5.40 mA cm−2. We show that mild post-fabrication hot plate annealing can improve the Jsc, but can in most cases compromise the Voc. The effect of sequential annealing was monitored by solar conversion efficiency and external quantum efficiency (EQE) measurements.

Bis-3-methylpyridine and bis-4-methylpyridine complexes of cadmium(II) ethylxanthate have been characterized by elemental analysis, NMR spectroscopy, and thermogravimetric analysis. The single crystal X-ray structures of both methylpyridine derivatives have also been determined and shown to display a cis, cis, cis-configuration of the N- and S-donor ligands. The compounds have been utilized as single source precursors to deposit CdS films on silica-coated glass substrates at 220 and 350 °C by aerosol-assisted chemical vapor deposition. The surface morphology of the films has been examined by scanning electron microscopy analysis and the crystalline phases were studied by powder X-ray diffraction. The films deposited from the 3-methylpyridine adduct comprised more densely packed and more highly crystalline hexagonal CdS than those provided by either of the other two precursors. The crystallite sizes were found to be

Photoelectrochemical water splitting is a promising technology for the development of solar fuels. Titanium dioxide TiO2 is one of the most studied metal oxides in this field as a photoanode. Achieving its full potential requires controlling its morphology and crystallinity and especially the exposure of its most active crystal facets. Herein, we present the formation of nanostructured TiO2 photoanodes with anatase phase and high exposure of the 0 1 0 facet, the most active TiO2 phase and facet. TiO2 photoanodes were prepared from a Ti7O4 OEt 20 titanium oxo alkoxy cluster solution using aerosol assisted chemical vapor deposition. Characterization techniques such as SEM and TEM reveal that these TiO2 photoanodes consist of morphologies resembling the crystals of gypsum, sand and water found in nature, also known as desert roses. Furthermore, TEM and XRD analysis also reveals that the metastable anatase TiO2 phase is maintained up to 1000 C and exceeds the typical anatase to rutile phase transition temperature of 500 750 C, a feature that could be exploited in the smart ceramics industry. Photoelectrochemical measurements show that these desert rose TiO2 photoanodes achieve excellent photocurrent densities with an incident photon to current efficiency of amp; 8764;100 at 350 nm and a faradaic efficiency for oxygen evolution of amp; 8764;90

We report the development of a true single source precursor (i.e. without any need for an exogenous source of oxygen) for the growth of zirconia thin films by aerosol-assisted chemical vapour deposition (AACVD) using an original family of zirconium(IV) amidate derivatives, which are easily prepared by protonolysis of [Zr(NMe2)4] with the free amide pro-ligands. In all but one case the reactions resulted in the isolation of the corresponding homoleptic eight-coordinate zirconium(IV)tetrakis(amidato) derivatives. Three of these species along with a tris(amidato)dimethylamido zirconium(IV) derivative have been characterised by single crystal X-ray diffraction analysis. The materials potential of the homoleptic compounds was identified through the application of design criteria derived from consideration of the existing knowledge base relating to the pyrolysis of wholly organic amides. In this manner the thermal decomposition of the homoleptic derivatives benefits from facile, molecularly imposed pyrolysis pathways, which provide for the privileged generation of volatile small molecule by-products and the production of contaminant-free solid oxide material. Thermogravimetric analysis, in conjunction with NMR spectroscopic analysis of the volatile products resulting from their thermal decomposition, indicated the potential of the homoleptic species as exquisite single source precursors to ZrO2 at moderate temperatures. The compound bearing both N- and C-iso-propyl substituents was, thus, applied as a true single source precursor under ambient pressure AACVD conditions. The resultant films, deposited on either SiO2-coated glass or quartz substrates, are smooth and comprise small and densely packed crystalline particulates that are shown by XRD to be primarily cubic ZrO2. Compositional analysis by X-ray photoelectron spectroscopy (XPS) revealed that the oxygen delivered, and the decomposition pathway provided, by the amidate ligand structure yields ZrO2 films which, though slightly sub-stoichiometric (ZrO1.8–1.9), contain undetectable levels of carbon incorporation.

Metal chalcogenide thin films have a wide variety of applications and potential uses. Tin(II) Sulfide, is one such materi-al which presents a significant challenge with the need for high quality SnS, free of oxide materials (e.g. SnO2) oxides and higher tin sulfides (e.g. Sn2S3 and SnS2). This problem is compounded further when the target material exhibits a number of polymorphic forms with different optoelectronic properties. Unlike conventional chemical vapor deposition (CVD) and atomic layer deposition (ALD), which relies heavily on having precursors that are volatile, stable and reac-tive, the use of aerosol assisted CVD (AA-CVD) negates the need for volatile precursors. We report here, for the first time, the novel and structurally characterized single source precursor (1), Dimethylamido-(N-Phenyl-N’,N’-Dimethyl-Thiouriate)Sn(II) dimer, and its application in the deposition, by AA-CVD, of phase-pure films of SnS. A mechanism for the oxidatively controlled formation of SnS from precursor (1) is also reported. Significantly, thermal control of the deposition process allows for the unprecedented selective and exclusive formation of either orthorhombic-SnS (α-SnS) or zinc blende-SnS (ZB-SnS) polymorphs. Thin films of α-SnS or ZB-SnS have been deposited onto Mo, FTO, Si and glass substrates at the optimized deposition temperatures of 375 oC and 300 oC, respectively. The densely packed poly-crystalline thin films have been characterized by XRD, SEM, AFM, Raman spectroscopy, EDS and XPS analysis. These data confirmed the phase purity of the SnS formed. Optical analysis of the α-SnS and ZB-SnS films show distinctly dif-ferent optical properties with direct band gaps of 1.34 eV and 1.78 eV, respectively. Furthermore photoelectrochemical and external quantum efficiency (EQE) measurements were undertaken to assess the optoelectronic properties of the deposited samples. We also report for the first time the ambipolar properties of the ZB-SnS phase.

Hybrid organic–inorganic perovskites have been established as good candidate materials for emerging photovoltaics, with device efficiencies of over 22% being reported. There are currently only two organic cations, methylammonium and formamidinium, which produce 3D perovskites with band gaps suitable for photovoltaic devices. Numerous computational studies have identified azetidinium as a potential third cation for synthesizing organic–inorganic perovskites, but to date no experimental reports of azetidinium containing perovskites have been published. Here we prepare azetidinium lead iodide for the first time. Azetidinium lead iodide is a stable, bright orange material which does not appear to form a 3D or a 2D perovskite. It was successfully used as the absorber layer in solar cells. We also show that it is possible to make mixed cation devices by adding the azetidinium cation to methylammonium lead iodide. Computational studies show that the substitution of up to 5% azetidinium into the methylammonium lead iodide is energetically favourable and that phase separation does not occur at these concentrations. Mixed azetidinium–methylammonium cells show improved performance and reduced hysteresis compared to methylammonium lead iodide cells.

Two thioamide pro-ligands, R1N(H)C(S)R2 (R1 = t-Bu, R2 = i-Pr and R1 = i-Pr, R2 = i-Pr), were synthesized by treatment of the corresponding amides with Lawesson’s reagent. Reactions of [Sn{N(SiMe3)2}2] with two molar equivalents of 7 each thioamide pro-ligand yielded the tin(II) thioamidate species, bis(2-methyl-N-(1-methylethyl)-propanethioamide)tin(II) and bis[N-(1,1-dimethylethyl)-2-methylpropanethioamide]tin(II). Both of the new tin compounds have been characterized by 1H, 1C, and 119Sn NMR spectroscopy and elemental analysis. In addition, the solid-state structure of bis(2-methyl-N-(1-methylethyl)-10 propanethioamide)tin(II) has been determined through a single crystal X-ray diffraction analysis and shown to display a 11 monomeric constitution in which the tin(II) center occupies a distorted pseudosquare pyramidal geometry defined by the N2S2 donors and the stereochemically active lone pair. Both tin(II) derivatives have been assessed for their potential as single source precursors to SnS by TGA and by NMR spectroscopic analysis of the volatile organic products produced during their thermolysis. Both compounds have been utilized in the growth of thin films by aerosol-assisted chemical vapor deposition (AACVD). These latter studies provided film growth at temperatures as low as 200 °C. The films have been analyzed by pXRD, Raman spectroscopy, XPS, AFM, and SEM and are shown to comprise primarily the orthorhombic (Herzenbergite) phase of SnS, which is contaminated by only low levels of residual carbon (

[Sn6 (O)4 (OSiMe3 )4 ] and [{Sn(OSiMe3 )2 }2 ] have been used to deposit SnO thin films by chemical vapour deposition. Films derived from [Sn6 (O)4 (OSiMe3 )4 ] comprise uniform cubes and are highly oriented, whereas those deposited from [{Sn(OSiMe3 )2 }2 ] are made up of a continuous non-oriented layer with oriented cubes on the surface. The structure of a co-crystal, 2 Sn6 (O)4 (OSiMe3 )4 ⋅[Sn(OSiMe3 )2 ]2 ⋅4 THF, shows that [{Sn(OSiMe3 )2 }2 ], a liquid at room temperature, adopts a μ-OSiMe3 -bridged dimeric structure. [Sn6 (O)4 (OSiMe3 )4 ] reacts with O2 in a controlled manner to afford the novel oxo-cluster [Sn4( O)(OSiMe3 )8 ], the structure of which is reported. In addition, a crystal of {[Sn4 (O)(OSiMe3 )5 ]+2 [Sn(O)(OSiMe3 )4 Cl]+2 }[Cl]-4 has been fortuitously isolated from the presence of SnCl2 in the starting material for the preparation of [Sn6 (O)4 (OSiMe3 )4 ], and has been shown to incorporate two novel cationic oxo-tin clusters.

The structures of the Group 1 metal aminoalkoxides Li[OCH(CH2CNMe2)2] (1) and K[OCH(CH2CNMe2)2]∙HOCH(CH2CNMe2)2 (2) have been determined. 1 is a hexa­meric drum in which two Li3O3 rings are joined co-facially, whereas 2 is tetrameric and adopts a K4O4 ladder structure, novel for homoleptic potassium alkoxides.

Cadmium burning: The violent reaction of CdMe 2 with O 2 has been controlled by the use of a cadmium aminoalkoxide supporting ligand. The first examples of cadmium organoperoxides, arising from O 2 insertion into the Cd C bond, are thus formed (see picture; Cdgreen, Cgray, Nblue, Ored).

An air and moisture stable C(3)-symmetric titanium(IV) triflate, supported by a tripodal amine-(tris-phenolate) ligand, has been synthesized and characterized by X-ray crystallography and shown to be a good Lewis acid catalyst for a range of aza-Diels-Alder, Diels-Alder, syn aldol, allylation, and alkylation reactions.

The amine elimination reaction of W(NtBu)2(NHtBu)2 with the di-basic carborane acid nido-7,8-C2B9H13 generates the tungsten(VI) carborane complex, [W(NtBu)(NHtBu)2(C2B9H11)] 1, in which a C2B9H11 ligand has replaced one imido ligand. One of the remaining amido ligands can be substituted by acidic functions, thus 2,6-dimethylphenol yields [W(NtBu)(NHtBu)(2,6-Me2C6H3O)(C2B9H11)] 2, and water gives the μ-oxo complex {[W(NtBu)(NHtBu)(C2B9H11)]2(μ-O)} 3 as a mixture of racemic and meso diastereomers. Complexes 1 and 2 have been characterised by single crystal X-ray diffraction, revealing that replacing an amido ligand in 1 by a weaker π-donor phenoxide in 2 results in shorter metal–amido and metal–dicarbollide distances. Substitution of one amido ligand in 1 by a chloro ligand is achieved using Me3SiCl giving [W(NtBu)(NHtBu)Cl(C2B9H11)] 4. Insertion of acetonitrile into the tungsten amido bond, followed by proton transfer gives {W(NtBu)2[N(H)C(Me)NHtBu](C2B9H11)} 5, the N-tert-butyl acetamidine adduct of the unknown M(1σ2π)3 complex [W(NtBu)2(C2B9H11)]. A structural study by X-ray diffraction reveals that compound 5 contains one short linear (W–N 1.750(3) A; W–N–C 173.8(3)°) and one longer bent (1.795(3) A, 151.4(3)°) imido ligand, with a hydrogen bond between the amidine and bent imido ligand, demonstrating for the first time that a sp2 hybridised bent imido ligand can act as a hydrogen bond acceptor.

Reactions of M(NMe2)5 (M = Ta or Nb) with nido-2,9-C2B9H13 and the salt [Me3NH][nido-7,9-C2B9H12] gave the isomeric dicarbollide complexes [2,2,2-(NMe2)3-closo-2,1,12-MC2B9H11] (M = Ta 1, Nb 4) and [2,2,2-(NMe2)3-closo-2,1,7-MC2B9H11] (M = Ta 2, Nb 5) respectively. The structures of 1 and 2 were determined by single crystal X-ray diffraction and 1 represents the first structurally characterised example of a 2,1,12-MC2B9 metallacarborane. Comparison of 11B NMR data of the tantalum complexes, along with the isomeric [3,3,3-(NMe2)3-closo-3,1,2-TaC2B9H11] 3, with that of 1,2-, 1,7- and 1,12-C2B10H12, reveals that the metal vertex {Ta(NMe2)3}, on replacing a {BH} vertex, influences significantly the boron NMR shifts of the neighbouring and antipodal cage atoms. Based on this observation the assignments of the reported peaks in the boron NMR data for the seven isomers of (η5-C5H5)CoC2B9H11 are tentatively predicted.

The tantalum complex [closo-3,1,2-Ta(NMe2)3(C2B9H11)] underwent insertion into the NC bond of acetonitrile and p-fluorobenzonitrile to give the N,N-dimethylacetamidinate complex [closo-3,1,2-Ta{NC(Me)NMe2}3(C2B9H11)], and p-fluoro-N,N-dimethylbenzamidinate, [closo-3,1,2-Ta{NC(C6H4F)NMe2}3(C2B9H11)], respectively. Attempted re-crystallisation of the latter from chlorinated solvents led to [closo-3,1,2-Ta{NC(C6H4F)NMe2}2Cl(C2B9H11)], in which one amidinate ligand has been replaced by a chloride. [closo-3,1,2-Ta(NMe2)3(C2B9H11)] reacts with cyclohexylisocyanide to give [Ta(NMe2)2{η2-N(Cy)CNMe2}(C2B9H11)]. The structures of the novel N,N-dialkylamidinate complexes have been determined by single crystal X-ray diffraction, and reveal the extensive delocalisation and strong π-donor character of the amidinate ligands. The M–N bonds of [closo-3,1,2-Ta(NMe2)3(C2B9H11)] are cleaved by protic reagents, and it reacts with 2,6-dimethylphenol to give [closo-3,1,2-Ta(OC6H3Me2-2,6)3(C2B9H11)] and with benzenethiol to give the charge-compensated complex [closo-3-Ta(SC6H5)4(9-NHMe2-1,2-C2B9H10)] where the β-boron of the C2B3 face bears a NHMe2+ substituent. The structures of the last two compounds have also been determined.

The homoleptic amides [M(NMe2)5] (M = Nb 1 or Ta 2; the latter is characterised by a structural study) reacted with the carborane nido-C2B9H13 to eliminate two equivalents of HNMe2 and generate the dicarbollide half-sandwich tris(dimethylamide) complexes [M(C2B9H11)(NMe2)3] (M = Nb 3 or Ta 4). The crystal structures of isomorphous 3 and 4 have been determined and reveal two NMe2 ligands in a vertical orientation and the third one in a horizontal orientation with respect to the η5-co-ordinated face of the C2B9H11 ligand. The electronic factors responsible for the amide ligand orientations in these complexes are explored using qualitative MO arguments. Complexes 3 and 4 reacted with CO2 and CS2 to yield the tris(carbamate) [M(C2B9H11)(O2CNMe2)3] (M = Nb 5 or Ta 7) and tris(dithiocarbamate) [M(C2B9H11)(S2CNMe2)3] (M = Nb 6 or Ta 8) complexes, respectively. The crystal structures of 6 and 7 show two (dithio)carbamate ligands in horizontal and one in vertical orientation, demonstrating the similarity between the σ,π-donor frontier orbitals of the ligands NMe2 and X2CNMe2 in 4 and 6 or 7 respectively.

An easily synthesised Sn(II) bis(ureide) derivative is shown to be a single-source precursor for the aerosol-assisted CVD of SnO, providing unprecedented levels of oxidation state control at temperatures as low as 250 °C.

We report the first synthesis of a cobalt Cp diene complex wherein the diene is derived by microbial dearomatising dihydroxylation of an aromatic ring. The complex has been characterised crystallographically and its structure is compared to that of an uncomplexed diene precursor.

A cyclohexadiene ligand prepared by microbial arene 1,2-dihydroxylation undergoes spontaneous rearrangement upon complexation to tricarbonyliron(0). Subsequent iron removal affords a novel route to formal arene 2,3-dihydroxylation products enantiomeric to those obtainable by direct microbial arene oxidation.

An air- and moisture-stable titanium(IV) triflate, 3, supported by a C3-symmetric amine tris(phenolate) ligand has been synthesised, characterised by X-ray crystallography and demonstrated to be an excellent catalyst for formal aza-Diels–Alder reactions.

This paper details the synthesis, characterisation including crystal structure, and testing for antimicrobial efficacy of two compounds: a zinc centred bis(N-allylsalicylideneiminato)-zinc (ZSB) and its known copper analogue, bis(N-allylsalicylideneiminato)-copper (CSB). Differences in antimicrobial efficacy of the two compounds were observed, suggesting possible mechanisms for antimicrobial activity. The ZSB system was plasma deposited under various pulse conditions onto non-woven fabric, and the antimicrobial efficacy of the resultant film measured for Staphylococcus aureus and Pseudomonas aeruginosa. These results suggest the potential utility of this compound as an effective antimicrobial thin film, and confirm the critical role the ligands play in effecting antimicrobial activity.

This Chapter reviews the major advances in the chemistry of the Group 13 elements published in high impact peer-reviewed inorganic chemistry journals during 2011. As in previous years this review is not exhaustive; focusing on what the author believes to be significant works and contributions to the field. The author apologises in advance that not all work can be covered and afforded the same depth of coverage.

The alkane elimination reaction between ZnMe2 and [(NMe3H)+(nido-C2B9H12)–] gives the macropolyhedral dimer [(nido-C2B9H11)ZnNMe3]2, containing an unprecedented planar diamond-shaped Zn2B2 ring at its core.

Reaction of Zr(OiPr)4 or Sn[N(SiMe3)2]2 with the tris-phenol amine ligand H3L(Me/Me) results in the formation of zirconium or tin complexes containing the new C3-symmetric zwitterionic ammonium-trisphenolate ligand HL2−, while increasing the steric bulk of the ligand results in the isolation of a zirconium complex containing the known trianionic ligand L3−.

Deboronation of meta-carborane, closo-1,7-C2B10H12, with refluxing piperidine results in the quantitative formation of [(C5H10NH)2H+](nido-7,9-C2B9H12−) whose structure was determined by X-ray diffraction. Heating under vacuum liberates piperidine to give (C5H10NH2+)(nido-7,9-C2B9H12−). The reaction of meta-carborane with KOH in refluxing ethanol yields K+nido-7,9-C2B9H12− and the cage substituted anion 10-EtO-7,9-C2B9H11−. The protonated Proton Sponge salt (PSH+)(nido-7,9-C2B9H12−) (PS = 1,8-N,N,N′,N′-tetramethylnaphthalenediamine) was obtained by metathesis from the potassium salt, an X-ray crystallographic study located the bridging hydrogen in the anion on the open face between the two adjacent boron atoms. Anaerobic deboronation of para-carborane, closo-1,12-C2B10H12, with KOH in refluxing tetraglyme–toluene gives the potassium salt of nido-2,9-C2B9H12− from which 2,9-C2B9H13 was isolated in 45% yield by protonation. The salt (PSH+)(nido-2,9-C2B9H12−), obtained from nido-2,9-C2B9H13 and PS, was shown by single crystal X-ray crystallography to contain a hydrogen bridging two boron atoms opposite the carbon atom on the open face. Aerobic deboronation of para-carborane with KOH forms closo-1,10-C2B8H10 and 2-HO-closo-1,10-C2B8H9 in low yields. Fully assigned multinuclear NMR (11B, 13C and 1H) data are reported for the isomeric 7,8-, 7,9- and 2,9-nido-C2B9H12− anions and neutral 7,8- and 2,9-C2B9H13, and compared with computed shifts (at the GIAO B3LYP/6-311G* level) from optimized (at MP2/6-31G*) geometries.