Publications by authors named "Charman R"

Copper is ubiquitous as a structural material, and as a reagent in (bio)chemical transformations. A vast number of chemical reactions rely on the near-inevitable preference of copper for positive oxidation states to make useful compounds. Here we show this electronic paradigm can be subverted in a stable compound with a copper-magnesium bond, which conforms to the formal oxidation state of Cu(-I).

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The intricate σ and π-bonding of N-heterocyclic carbenes (NHCs) to metals and the need to quantify their electronic properties to rationalize reactivity of complexes have resulted in the creation of numerous methodologies to understand the NHC-metal interaction which are, as we now show, flawed. Our search for a unified, easily accessible system to gauge these fundamental properties has resulted in the discovery of two systems that highlight the flaws present in existing systems and provide a more accurate measure of the NHC ligand electronic properties.

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Article Synopsis
  • Organogermane and organostannane compounds play a crucial role in cross coupling reactions, and copper(I) complexes help in accessing these valuable reagents.
  • This review explores the chemistry of copper(I) germanide and stannanide complexes, noting their structural characteristics and how they compare to silanide compounds.
  • Key differences include the way germanides and stannanides can produce organotetranes from their tetranes, with catalytic reactions being more successful for germanium, while triphenylstannanides uniquely yield phenyl anions, a process not found in silicon or germanium.
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A process for the catalytic reduction of nitrous oxide using NHC-ligated copper(I) tert-butoxide precatalysts and Bpin as the reductant is reported. These reactions proceed under mild conditions via copper(I)-boryl intermediates which react with NO by facile O-atom insertion into the Cu-B bond and liberate N. Turnover numbers >800 can be achieved at 80 °C under 1 bar NO.

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Article Synopsis
  • * Researchers developed a strategy targeting bacterial nucleotide excision repair (NER) and screened ~120,000 compounds to identify potential antimicrobial sensitizers, leading to the discovery of Bemcentinib (R428) as a promising candidate.
  • * Bemcentinib inhibits the NER protein UvrA's ATPase activity and DNA binding, effectively reducing its DNA repair capabilities, and shows significant growth inhibition of E. coli when combined with DNA-damaging agents like cisplatin, suggesting its potential as an adjuvant in cancer therapy.
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Liquid assisted ball milling of [NHC]HBr (NHC = N-heterocyclic carbene) salts with copper(I) chloride, and a range of alkali metal complexes was shown to efficiently produce (NHC)CuX (NHC = normal or RE-NHC, X = halide, alkoxide, amide, alkyl, aryl; RE-NHC = ring-expanded NHC).

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Deprotonation of triphenyl germane with NHC-supported copper alkoxides afforded four novel (NHC)CuGePh complexes. Of these, (IPr)CuGePh (IPr = :C{N(2,6-iPrCH)CH}) was selected for further investigation. Analysis by EDA-NOCV indicates it to be a germyl nucleophile and its σ-bond metathesis reaction with a range of p-block halides confirmed it to be a convenient source of [PhGe].

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Reaction of (6-Dipp)CuOtBu (6-Dipp=C{NDippCH } CH , Dipp=2,6-iPr C H ) with B (OMe) provided access to (6-Dipp)CuB(OMe) via σ-bond metathesis. (6-Dipp)CuB(OMe) was characterised by NMR spectroscopy and X-ray crystallography and shown to be a monomeric acyclic boryl of copper. (6-Dipp)CuB(OMe) reacted with ethylene and diphenylacetylene to provide insertion compounds into the Cu-B bond which were characterised by NMR spectroscopy in both cases and X-ray crystallography in the latter.

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Many protein interactions with DNA are reliant on the presence of specific DNA sequences, adducts, or structures. In bulk-phase experiments such DNA features are facile to include in a study. For single-molecule imaging this can be more difficult, because the constraints of the assay limit the variety of adducts that can be used.

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Exposure to UV radiation results in numerous DNA lesions, which threaten genome integrity. The nucleotide excision DNA repair pathway detects and repairs a range of such UV-induced DNA lesions. In bacteria, initial damage detection and verification is carried out by two proteins: UvrA and UvrB.

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Three ring-expanded N-heterocyclic carbene-supported copper(I) triphenylstannyls have been synthesised by the reaction of (RE-NHC)CuOBu with triphenylstannane (RE-NHC = 6-Mes, 6-Dipp, 7-Dipp). The compounds were characterised by NMR spectroscopy and X-ray crystallography. Reaction of (6-Mes)CuSnPh with di--tolyl carbodiimide, phenyl isocyanate and phenylisothiocyanate gives access to a copper(I) benzamidinate, benzamide and benzothiamide respectively phenyl transfer from the triphenylstannyl anion with concomitant formation of (PhSn).

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Reaction of bis(pinacolato)diboron with (6-Dipp)CuOBu generates a ring-expanded N-heterocyclic carbene supported copper(I) boryl, (6-Dipp)CuBpin. This compound showed remarkable stability and was characterised by NMR spectroscopy and X-ray crystallography. (6-Dipp)CuBpin readily dechalcogenated a range of heterocumulenes such as CO, isocyanates and isothiocyanates to yield (6-Dipp)CuXBpin (X = O, S).

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Article Synopsis
  • A Dalitz plot analysis was conducted on decay data from collisions at specific energies, yielding meaningful results.
  • An exotic resonant state was identified, showing significant presence with a significance level exceeding three standard deviations.
  • The study also provided the first measurement of the branching fraction, detailing uncertainties from statistical, systematic, and external factors.
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Three foals aged between 21 and 44 days were presented for evaluation of pyrexia and lameness. Each had subcutaneous abscessation associated with osteomyelitis of a rib at the costochondral junction and pathological fracture of the affected rib; one foal had more than one rib affected. Other localised sites of infection included other sites of osteomyelitis, omphalophlebitis, uveitis, enterocolitis, and calcaneal bursitis.

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Unlabelled: Carpal flexural deformities (CFD) are frequently encountered in the horse, with both congenital and acquired forms described. The success of surgical correction of CFD, both in terms of the ability to achieve a straight palmar carpal angle and the impact on future athletic performance, requires further investigation.

Objective: To report the surgical management and outcome of treatment of flexural deformity of the carpus in 72 horses up to 12 months of age.

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Chronic facial defects extending into the sinuses of two mares were repaired using periosteal flaps. Partial osseous bridging was established over the defects following repair. Previous attempts to close the defects with skin alone had failed.

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Healers claim that they can relieve, and often heal, injury and illness against the odds of medical prognosis. Skeptics say that such claims can be accounted for by possible misdiagnosis, uncritical reportage, placebo response, and coincident natural improvement. Their a priori objection is that subjective intention in one person cannot, of itself, affect the physiology and/or mental processes of another person.

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Five years ago, a task force on reducing risk for heart disease and stroke was established by the six New England States. The task force included representatives from State public health departments, academia, the corporate sector, and voluntary organizations. This article is the final report of the task force.

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A program was designed to evaluate the efficacy and cost of detecting and treating hypertension in an industrial population of a rural state. Original screening and evaluation was initiated by a trained blood-pressure technician team, but initiation of therapy was the responsibility of the private physician. Follow-up data were obtained at one year by rescreening in 83% and by telephone contact in 91% of the original hypertensive patients.

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Many problems remain in attempting to improve the detection and management of hypertension in the United States. This study applied a previously established model community hypertension program to a wide geographic area in a rural state. In 47 industries in 18 communities, 15,689 subjects were screened for the presence of hypertension.

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