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In this work, ambient pressure x-ray photoelectron spectroscopy (APXPS) is used to study the initial stages of water adsorption on vanadium oxide surfaces. V 2p, O 1s, C 1s, and valence band XPS spectra were collected as a function of relative humidity in a series of isotherm and isobar experiments. Experiments were carried out on two VO2 thin films on TiO2 (100) substrates, prepared with different surface cleaning procedures. Hydroxyl and molecular water surface species were identified, with up to 0.5 ML hydroxide present at the minimum relative humidity, and a consistent molecular water adsorption onset occurring around 0.01% relative humidity. The work function was found to increase with increasing relative humidity, suggesting that surface water and hydroxyl species are oriented with the hydrogen atoms directed away from the surface. Changes in the valence band were also observed as a function of relative humidity. The results were similar to those observed in APXPS experiments on other transition metal oxide surfaces, suggesting that H2O-OH and H2O-H2O surface complex formation plays an important role in the oxide wetting process and water dissociation. Compared to polycrystalline vanadium metal, these vanadium oxide films generate less hydroxide and appear to be more favorable for molecular water adsorption.

Heterobimetallic cages built from Pd and either octahedral Ru or square-planar Pt moieties and bridged by ligands with H bonding-accepting or -donating properties are reported. They showed stimulus-responsive dis- and reassembly, while guest binding was found to be dependent on the complementary properties of the guest to the host in terms of charge, size and H bonding properties. [ABSTRACT FROM AUTHOR]

Metal piano-stool complexes based on pyridinecarbothioamide (PCA) have shown promising antiproliferative and in vivo anticancer activity, in particular [Ru(cym)(p -F-PCA)Cl]PF6 (cym is η 6- p -cymene; plecstatin-1). The impact of modifications of the PCA and π-bound ligands on biological properties has been extensively investigated. Herein, we explored the influence of exchanging the chlorido ligand with the N -heterocycles 1-methylimidazole, 1-methylbenzimidazole and pyridine. In solution, an equilibrium between the protonated and deprotonated forms of the thioamide bond was observed, which was found dictated by the solvent system with both species detected in polar solvents. [Ru(cym)(PCA)Cl]+ complexes exhibit unique behaviour in an aqueous environment where they rapidly form dimeric species after substitution of the chlorido ligand for the sulfur donor of the PCA ligand of a second complex molecule. This was also observed for the synthesised complexes with the N -heterocyclic ligands being cleaved from the Ru centre allowing for dimerisation, which may be reversed by acidification of the solution resulting in the formation of equivalent mononuclear compounds. This behaviour explains the similar biological properties of the complexes with respect to that of plecstatin-1. Replacing the chlorido ligand in [Ru(η 6- p -cymene)(p -fluoropyridinecarbothioamide)Cl]PF6 with the N -heterocycles 1-methylimidazole, 1-methylbenzimidazole and pyridine gave complexes with similar antiproliferative activities in human cancer cells at low micromolar concentrations. This can be explained by dimerisation in aqueous solution and formation of the same di-Ru complexes after cleaving of the chlorido or N -heterocycle ligands. (Image credit: Saawan Kumar.) This article belongs to the 10th Anniversary Collection of RACI and AAS Award papers. [ABSTRACT FROM AUTHOR]

Co(III) complexes of the N-heterocyclic carbene ligand PY4Im (PY4Im = (1,3-bis(bis(2-pyridyl)methyl)imidazol-2-ylidene)) having the general formula [(PY4Im)Co(X)](ClO4)n (X = NCMe; n = 3: OH−, N3−, NCS−, ONO−, F−; n = 2: O2CO2−, n = 1; (N3−)3, n = 0) were prepared and structurally characterised. X-ray structural data are consistent with the presence of a trans influence due to the coordinated carbene carbon, and this is also supported by computational results. 13C NMR spectra of the complexes did not display peaks corresponding to the carbene carbon, except in the case of the [(PY4Im)Co(O2CO)]+ cation, where a peak at δ = 170.21 ppm was observed. However, HMBC spectra allowed indirect determination of the chemical shifts of the carbene carbon in the remaining complexes, owing to the geometry of the PY4Im ligand. Calculated 13C chemical shifts for the complexes showed very good agreement with the experimental values for all but the carbene carbon atoms in all cases. [ABSTRACT FROM AUTHOR]

Orthopedic implants provide patients with an opportunity to regain functionality lost from illness, disease, or injury. Recent advancements in additive manufacturing (AM) techniques have allowed for the increased customization of Ti‐6Al‐4V ELI (extra low interstitials) implants to complement natural variations in the human anatomy. Yet, the low bioactivity of Ti‐6Al‐4 V ELI and possible adverse effects from the leeching of aluminum and vanadium complicate the post‐operation recovery process. In this work, Ti‐6Al‐4 V ELI samples are printed using the electron beam melt technique in two directions and coated with diamond‐like carbon (DLC) to examine whether their biological properties can be improved. By conducting in vitro studies with Saos‐2 osteosarcoma cells, the effects of morphology and surface chemistry are correlated to the bioactivities of the coated and uncoated samples. The outcome of the study suggested that DLC coating is a viable method for controlling the surface bioactivity of a material. It indicates that a carbon coating, along with an appropriate topography, has the potential to promote the proliferation and maturity of bone cells and hence enhance the performance of additively manufactured products in next‐generation biomedical applications. [ABSTRACT FROM AUTHOR]