Chem Commun (Camb)
September 2023
A multi-component coordination compound, in which ruthenium antenna complexes are connected to a polyoxotungstate core is presented. This hybrid cluster effectively promotes the electrochemical conversion of CO to C1 feedstocks, the selectivity of which can be controlled by the acidity of the media.
View Article and Find Full Text PDFHerein, we report the synthesis and characterization of a new class of hybrid Wells-Dawson polyoxometalate (POM) containing a diphosphoryl group (P O X) of the general formula [P W O (P O X)] (X=O, NH, or CR R ). Modifying the bridging unit X was found to impact the redox potentials of the POM. The ease with which a range of α-functionalized diphosphonic acids (X=CR R ) can be prepared provides possibilities to access diverse functionalized hybrid POMs.
View Article and Find Full Text PDFThe mixing of [V O ] decavanadate anions with a dicationic gemini surfactant (gem) leads to the spontaneous self-assembly of surfactant-templated nanostructured arrays of decavanadate clusters. Calcination of the material under air yields highly crystalline, sponge-like V O (gem-V O ). In contrast, calcination of the amorphous tetrabutylammonium decavanadate allows isolation of a more agglomerated V O consisting of very small crystallites (TBA-V O ).
View Article and Find Full Text PDFHealth care organizations are obligated to provide safe and effective treatment to their patients and also protect the safety of their workers. This paper analyzes the tensions arising from legislative regimes that, respectively, protect privacy and workplace safety, using a large, tertiary high-secure forensic psychiatric hospital in Ontario, Canada, as an example. In Ontario, the Personal Health Information Protection Act (PHIPA) prohibits personal health information (PHI) from being disclosed to individuals who fall outside the "circle of care," including nonclinical employees who have direct involvement with patients and may be at risk of violence.
View Article and Find Full Text PDFWe describe the preparation of hybrid redox materials based on polyoxomolybdates encapsulated within single-walled carbon nanotubes (SWNTs). Polyoxomolybdates readily oxidize SWNTs under ambient conditions in solution, and here we study their charge-transfer interactions with SWNTs to provide detailed mechanistic insights into the redox-driven encapsulation of these and similar nanoclusters. We are able to correlate the relative redox potentials of the encapsulated clusters with the level of SWNT oxidation in the resultant hybrid materials and use this to show that precise redox tuning is a necessary requirement for successful encapsulation.
View Article and Find Full Text PDFThere are few nationwide descriptive studies of longitudinal drug use and residual cardiovascular risk in patients with myocardial infarction (MI) in contemporary clinical practice. The objectives of this work were to describe characteristics and longitudinal cardiovascular drug use of patients with a first acute MI in Norway, and to quantify residual risks of cardiovascular events and death. Using nationwide health registries in Norway, we identified 43 750 adults with a first MI (2010 to 2015) and ≥1 prescription for antiplatelet medication.
View Article and Find Full Text PDFThis review provides a comprehensive overview of recent advances in the supramolecular organisation and hierarchical self-assembly of organo-functionalised hybrid polyoxometalates (hereafter referred to as hybrid POMs), and their emerging role as multi-functional building blocks in the construction of new nanomaterials. Polyoxometalates have long been studied as a fascinating outgrowth of traditional metal-oxide chemistry, where the unusual position they occupy between individual metal oxoanions and solid-state bulk oxides imbues them with a range of attractive properties ( solubility, high structural modularity and tuneable properties/reactivity). Specifically, the capacity for POMs to be covalently coupled to an effectively limitless range of organic moieties has opened exciting new avenues in their rational design, while the combination of distinct organic and inorganic components facilitates the formation of complex molecular architectures and the emergence of new, unique functionalities.
View Article and Find Full Text PDFThis Tutorial Review describes how the development of dissolved redox-active molecules is beginning to unlock the potential of three of the most promising 'next-generation' battery technologies - lithium-air, lithium-sulfur and redox-flow batteries. Redox-active molecules act as mediators in lithium-air and lithium-sulfur batteries, shuttling charge between electrodes and substrate systems and improving cell performance. In contrast, they act as the charge-storing components in flow batteries.
View Article and Find Full Text PDF3D printable materials based on polymeric ionic liquids (PILs) capable of controlling the synthesis and stabilisation of silver nanoparticles (AgNPs) and their synergistic antimicrobial activity are reported. The interaction of the ionic liquid moieties with the silver precursor enabled the controlled in situ formation and stabilisation of AgNPs via extended UV photoreduction after the printing process, thus demonstrating an effective decoupling of the device manufacturing from the on-demand generation of nanomaterials, which avoids the potential aging of the nanomaterials through oxidation. The printed devices showed a multi-functional and tuneable microbicidal activity against Gram positive (B.
View Article and Find Full Text PDFAn asymmetrically functionalised Wells-Dawson organic-inorganic hybrid polyoxometalate has been post-functionalised by Pt coordination, and demonstrates self-assembly into surface-decorated micellar nanostructures. This multifunctional hybrid material is found to be a redox-active soft nanomaterial and demonstrates a new molecular design strategy with potential for applications in photo- or electro-catalysis.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
August 2020
We report the design and preparation of multifunctional hybrid nanomaterials through the stabilization of gold nanoparticles with thiol-functionalised hybrid organic-inorganic polyoxometalates (POMs). The covalent attachment of the hybrid POM forms new nanocomposites that are stable at temperatures and pH values which destroy analogous electrostatically functionalised nanocomposites. Photoelectrochemical analysis revealed the unique photochemical and redox properties of these systems.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2019
Access to asymmetrically functionalized polyoxometalates is a grand challenge as it could lead to new molecular nanomaterials with multiple or modular functionality. Now, a simple one-pot synthetic approach to the isolation of an asymmetrically functionalized organic-inorganic hybrid Wells-Dawson polyoxometalate in good yield is presented. The cluster bears two organophosphonate moieties with contrasting physical properties: a chelating metal-binding group, and a long aliphatic chain that facilitates solvent-dependent self-assembly into soft nanostructures.
View Article and Find Full Text PDFA mononuclear Fe complex, prepared with a Brønsted diacid ligand, H L (H L=2-[5-phenyl-1H-pyrazole-3-yl] 6-benzimidazole pyridine), shows switchable physical properties and was isolated in five different electronic states. The spin crossover (SCO) complex, [Fe (H L) ](BF ) (1 ), exhibits abrupt spin transition at T =258 K, and treatment with base yields a deprotonated analogue [Fe (HL) ] (1 ), which shows gradual SCO above 350 K. A range of Fe analogues were also characterized.
View Article and Find Full Text PDFA new post-functionalization strategy for hybrid polyoxometalate (POM) clusters is presented, whereby the electronic properties and visible-light driven oxidative reactivity of the POM core can be altered by controlled addition of transition metal ions. The structure of three new metal-functionalised derivatives of a phosphonate hybrid-POM are discussed, alongside a comparison of their electrochemical, photo-chemical and photo-oxidative properties.
View Article and Find Full Text PDFFinding new ways of using visible light (or, more specifically, solar irradiation) to drive commercially significant and/or challenging chemical processes is an ongoing research goal. Polyoxometalates (POMs) are discrete, metal-oxide clusters which are cheap, robust and easily synthesised but can also act as versatile molecular building blocks, allowing for astonishing variety in their structures and properties. In particular, the rich redox chemistry and inherent photo-activity of POMs makes them attractive for use in a variety of photochemical applications, however POMs characteristically only absorb strongly in the UV region.
View Article and Find Full Text PDFThis study explores a new method to maximize the visible-light-driven photocatalytic performance of organic-inorganic hybrid polyoxometalates (POMs). Experimental and theoretical investigations of a family of phosphonate-substituted POMs show that modification of grafted organic moieties can be used to tune the electronic structure and photoactivity of the metal oxide component. Unlike fully inorganic polyoxotungstates, these organic-inorganic hybrid species are responsive to visible light and function as photocatalysts (λ > 420 nm) in the decomposition of a model environmental pollutant.
View Article and Find Full Text PDFThe design of highly flexible framework materials requires organic linkers, whereas inorganic materials are more robust but inflexible. Here, by using linkable inorganic rings made up of tungsten oxide (PWO) building blocks, we synthesized an inorganic single crystal material that can undergo at least eight different crystal-to-crystal transformations, with gigantic crystal volume contraction and expansion changes ranging from -2,170 to +1,720 Å with no reduction in crystallinity. Not only does this material undergo the largest single crystal-to-single crystal volume transformation thus far reported (to the best of our knowledge), the system also shows conformational flexibility while maintaining robustness over several cycles in the reversible uptake and release of guest molecules switching the crystal between different metamorphic states.
View Article and Find Full Text PDFWe have examined the remains of a Pilgrim burial from St Mary Magdalen, Winchester. The individual was a young adult male, aged around 18-25 years at the time of death. Radiocarbon dating showed the remains dated to the late 11th-early 12th centuries, a time when pilgrimages were at their height in Europe.
View Article and Find Full Text PDFA TTF-based (TTF=tetrathiafulvalene) tridentate ligand (α-(4'-methyl-4,5-di-n-dodecylthylthiotetrathiafulvalene-5'-ylthio)- α'-[2,2,2-tris(1-pyrazolyl)ethoxy]-p-xylene) (L) with long-chain alkyl moieties was prepared in order to obtain a new multi-redox active gelator based on a mixed-metal octanuclear complex [Fe Ni (CN) (tp) (L) ](BF ) (1). The magnetism, electrochemistry, and gelation behavior of 1 were studied and 1,2-dichlorobenzene solutions of 1 are shown to display thermoreversible gelation behavior at room temperature. Furthermore, the gel phase of 1 was shown to undergo room-temperature gel-to-sol transformations induced by both the oxidation and reduction of the gelator complex by F TCNQ or [Fe (Cp*) ], respectively.
View Article and Find Full Text PDFProprotein convertase subtilisin/kexin type 9 (PCSK9) binds to the low density lipoprotein receptor (LDLR) at the cell surface and is internalized as a complex with the LDLR. In the acidic milieu of the sorting endosome, PCSK9 remains bound to the LDLR and prevents the LDLR from folding over itself to adopt a closed conformation. As a consequence, the LDLR fails to recycle back to the cell membrane.
View Article and Find Full Text PDFTungsten-based polyoxometalates (POMs) have been employed as UV-driven photo-catalysts for a range of organic transformations. Their photoactivity is dependent on electronic transitions between frontier orbitals and thus manipulation of orbital energy levels provides a promising means of extending their utility into the visible regime. Herein, an organic-inorganic hybrid polyoxometalate, K [P W O (PO H C ) ]⋅6 C H NO, was found to exhibit enhanced redox behaviour and photochemistry compared to its purely inorganic counterparts.
View Article and Find Full Text PDFA cyanide-bridged [CoFe] cluster with trigonal bipyramidal geometry shows solvent-driven reversible on/off switching of its thermally induced electron-transfer-coupled spin transition (ETCST) behaviour.
View Article and Find Full Text PDFThe reactions of [γ-SiW10O36](8-) represent one of the most important synthetic gateways into a vast array of polyoxotungstate chemistry. Herein, we set about exploring the transformation of the lacunary polyoxoanion [β2-SiW11O39](8-) into [γ-SiW10O36](8-) using high-resolution electrospray mass spectrometry, density functional theory, and molecular dynamics. We show that the reaction proceeds through an unexpected {SiW9} precursor capable of undertaking a direct β → γ isomerization via a rotational transformation.
View Article and Find Full Text PDFWe report the formation of two polyoxotungstates of the general formula [M6(PW6O26)(α-P2W15O56)2(H2O)2](23-) (M = Co(II) or Mn(II)), which contain {PW6} fragments generated from the [P2W15O56](12-) precursor, which demonstrates for the first time the transformation of a Dawson lacunae into a Keggin lacunary building block. Solution analysis of the clusters has been conducted via electrospray ionisation mass spectrometry.
View Article and Find Full Text PDFWe report an approach to synthesize molecular tungsten-oxide-based pentagonal building blocks, in a new {W21 O72} unit, and show how this leads to a family of gigantic molecular architectures including [H12W48O164](28-) {W48}, [H20W56O190](24-) {W56}, and [H12W92O311](58-) {W92}. The {W48} and {W56} clusters are both dimeric species incorporating two {W21} units and the {W56} species is the first example of a molecular metal oxide cluster containing a chiral "double-stranded" motif which is stable in solution as confirmed by mass spectrometry. The {W92} anion having four {W21} units is one of the largest transition metal substituted isopolyoxotungstates known.
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