排序方式: 共有34条查询结果,搜索用时 468 毫秒
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Georgiy Akopov Nethmi W. Hewage Philip Yox Gayatri Viswanathan Shannon J. Lee Liam P. Hulsebosch Sarah D. Cady Alexander L. Paterson Frdric A. Perras Wenqian Xu Kui Wu Yaroslav Mudryk Kirill Kovnir 《Chemical science》2021,12(44):14718
An innovative method of synthesis is reported for the large and diverse (RE)6(TM)x(Tt)2S14 (RE = rare-earth, TM = transition metals, Tt = Si, Ge, and Sn) family of compounds (∼1000 members, ∼325 contain Si), crystallizing in the noncentrosymmetric, chiral, and polar P63 space group. Traditional synthesis of such phases involves the annealing of elements or binary sulfides at elevated temperatures. The atomic mixing of refractory components technique, presented here, allows the synthesis of known members and vastly expands the family to nearly the entire transition metal block, including 3d, 4d, and 5d TMs with oxidation states ranging from 1+ to 4+. Arc-melting of the RE, TM, and tetrel elements of choice forms an atomically-mixed precursor, which readily reacts with sulfur providing bulk powders and large single crystals of the target quaternary sulfides. Detailed in situ and ex situ experiments show the mechanism of formation, which involves multiphase binary sulfide intermediates. Crystal structures and metal oxidation states were corroborated by a combination of single crystal X-ray diffraction, elemental analysis, EPR, NMR, and SQUID magnetometry. The potential of La6(TM)x(Tt)2S14 compounds for non-linear optical applications was also demonstrated.Synthesis from atomically-mixed precursors opens up a phase space to hundreds of chiral and polar sulfide semiconductors with almost any transition metal in variable oxidation states. 相似文献
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Alexander AM Bria M Brunklaus G Caldwell S Cooke G Garety JF Hewage SG Hocquel Y McDonald N Rabani G Rosair G Smith BO Spiess HW Rotello VM Woisel P 《Chemical communications (Cambridge, England)》2007,(22):2246-2248
A ferrocene-functionalised ureidopyrimidinone has been synthesised that can signal the solvent-induced tautomerism of the dimeric 4[1H]-pyrimidinone form to the monomeric 6[1H]-pyrimidinone form. 相似文献
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Cooke G Garety JF Hewage SG Jordan BJ Rabani G Rotello VM Woisel P 《Organic letters》2007,9(3):481-484
[reaction: see text] A random copolymer containing 1,5-dialkyloxynaphthalene moieties has been synthesized using atom-transfer radical polymerization. We have shown that this polymer has the ability to form complexes with the tetracationic cyclophane cyclobis(paraquat-p-phenylene) (CBPQT(4+)) and that electrochemical reduction of the cyclophane or the addition of a competing guest for the cavity of the cyclophane results in disassembly of the supramolecular polymer. 相似文献
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J. W. Hewage W. L. Rupika F. G. Amar 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2012,66(11):1-7
Classical molecular dynamics simulation (MD) with Sutton-Chen potential has been used to generate the minimum energy and to study the thermodynamic and dynamic properties of mixed transition metal cluster motifs of Ag n Ni(13?n) for n ?? 13. Literature results of thirteen particle clusters of neat silver and nickel atoms were first reproduced before the successive replacement of the silver atom by nickel. Calculation was repeated for both silver-centred and nickel-centred clusters. It was found that the nickel-centred clusters were more stable than the silver-centred clusters. Heat capacities and hence the melting points of silver and nickel-centred clusters were determined by using the Histogram method. Species-centric order parameters developed by Hewage and Amar were used to understand the dynamic behaviour in the transition of silver-centred clusters to more stable nickel-centred clusters. This species-centric order parameter calculation further confirmed the stability of nickel-centred clusters over those of silver-centred species. 相似文献
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Graeme Cooke Patrice Woisel Marc Bria Shanika Gunatiliaka Hewage 《Tetrahedron letters》2006,47(36):6449-6452
We report the synthesis of a cyclodextrin-based molecular adapter which has the propensity to form an electrochemically tuneable ternary complex with cyclophanes 2 or 3 and ferrocene 4 in non-aqueous and aqueous environments, respectively. 相似文献
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Three sharp absorption features in the energy range 2.36–2.55 eV have been detected in the transmission spectrum of Co-diffused ZnSe, and a number of luminescence transitions originating from the lowest of these states at 2.361 eV have been observed. Photoluminescence excitation spectra prove that these are high energy excited states of the Co2+Zn impurity, a conclusion confirmed by comparison of measured and predicted luminescence energies. This represents the first identification of luminescence branching from a higher excited state of a transition metal ion in any semiconductor. The sharp, weakly phonon-coupled transitions involve either intra-impurity excitation or transitions from the impurity to localised states split off from a minimum in the conduction band. The implications of these observations for the mechanism of host-impurity energy transfer and for the nature of the excited state wavefunctions are discussed. 相似文献