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61.
The imidoiron(iv) species are relatively less explored compared to the oxoiron(iv) intermediates. Recently, generation and characterization of a novel imido/oxoiron(iv) species ([(N(4)Py)Fe(IV)[double bond, length as m-dash]X](2+) X = NTs; 1, O; 2) has been reported with an S = 1 ground state. Although the ground state for 1 and 2 are the same, they are reported to be distinctly different in other aspects. Unlike the oxoiron(iv) species, the Fe(iv) and nitrene combination in 1 lead to eight different spin states. Bearing in mind the complexity arising here, we have undertaken a detailed DFT study on this transient intermediate and probed its electronic structure and bonding in comparison to the oxoiron(iv) unit. Our Molecular Orbital, Energy Decomposition Analysis, and Natural Bond Orbital analysis indicates a weaker σ and non-degenerate π* orbitals for 1 in comparison to a stronger σ and degenerate π* orbitals for 2. The implication of these intricate bonding differences in reactivity is discussed along with the computation of absorption and other spectral parameters. Our results broadly support the proposed S = 1 ground state for 1 and provides some useful insight into its electronic structure. 相似文献
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G. Radha Krishna H. R. Ravindra B. Gopalan S. Syamsundar 《Journal of Radioanalytical and Nuclear Chemistry》1996,204(2):295-302
Tri-n-butyl phosphate (TBP) continues to be the most widely used solvent in nuclear fuel extraction, refining and reprocessing units for the extraction of actinides and their separation from fission products. An X-ray fluorescence spectrometric method (XRFS) for the determination of TBP content with an X-ray detectable element is presented. The method involves formation of an ion association complex of uranium with TBP-kerosene mixture in 3M nitric acid. The analytes uranium and bromine used as internal ratio elements in organic extract are excited by a primary X-ray beam from a rhodium tube. The solvent concentration is determined from the ratioed characteristic intensities of uranium and bromine. The procedure permits the determination of organic solvent in the range 0.5 to 5.0% with a relative standard deviation of 0.1%. 相似文献
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Jason F. Khoury Jiangang He Jonathan E. Pfluger Ido Hadar Mahalingam Balasubramanian Constantinos C. Stoumpos Rui Zu Venkatraman Gopalan Chris Wolverton Mercouri G. Kanatzidis 《Chemical science》2020,11(3):870
Subchalcogenides are uncommon, and their chemical bonding results from an interplay between metal–metal and metal–chalcogenide interactions. Herein, we present Ir6In32S21, a novel semiconducting subchalcogenide compound that crystallizes in a new structure type in the polar P31m space group, with unit cell parameters a = 13.9378(12) Å, c = 8.2316(8) Å, α = β = 90°, γ = 120°. The compound has a large band gap of 1.48(2) eV, and photoemission and Kelvin probe measurements corroborate this semiconducting behavior with a valence band maximum (VBM) of −4.95(5) eV, conduction band minimum of −3.47(5) eV, and a photoresponse shift of the Fermi level by ∼0.2 eV in the presence of white light. X-ray absorption spectroscopy shows absorption edges for In and Ir do not indicate clear oxidation states, suggesting that the numerous coordination environments of Ir6In32S21 make such assignments ambiguous. Electronic structure calculations confirm the semiconducting character with a nearly direct band gap, and electron localization function (ELF) analysis suggests that the origin of the gap is the result of electron transfer from the In atoms to the S 3p and Ir 5d orbitals. DFT calculations indicate that the average hole effective masses near the VBM (1.19me) are substantially smaller than the average electron masses near the CBM (2.51me), an unusual feature for most semiconductors. The crystal and electronic structure of Ir6In32S21, along with spectroscopic data, suggest that it is neither a true intermetallic nor a classical semiconductor, but somewhere in between those two extremes.Subchalcogenides are uncommon, and their chemical bonding results from an interplay between metal–metal and metal–chalcogenide interactions. 相似文献
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A. Gopalan S. Paulrajan N. R. Subbaratnam K. Venkata Rao 《Journal of polymer science. Part A, Polymer chemistry》1985,23(7):1861-1868
Polymerization of the symmetrical nonconjugated diolefin, N,N′-methylene bisacrylamide, was carried out using peroxodisulphate ion -Fe2+ as redox initiator. The rate of polymerization is found to depend on [M]3/2 and [S2O82?]1/2 and independent of [Fe2+] over a range. A polymerization mechanism involving cyclopolymerization in the propagation step is suggested. Evidence in favor of the cyclopolymerization mechanism is discussed. Evaluation of the rate parameters indicates that the deactivation of the primary radical SO4? by Fe2+ ion is a factor to be reckoned with. 相似文献
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This paper deals with the analysis of 1-server n-unit system. At t = 0, all the units are switched on. The repair times of the units are arbitrarily distributed, while the failure rates of the units are constants. The system is analysed by writing integral equations for the probabilities of the system being found in various states by identifying it at suitable regeneration epochs. These equations are solved using integral transforms. The following system characteristics, namely, 1) Expected duration in [0, t] k units are operating; 0 ≤ k ≤ n 2) Expected duration in [0, t] the server is busy with the repair of the units 3) Expected number of repairs in the interval [0, t] 4) Expected number of times the system enters down-state 5) Expected duration in [0, t] the system is in down-state are evaluated to carry out the analysis of the system 相似文献
70.
Dr. Stuart K. Langley Dr. Kuduva R. Vignesh Dr. Boujemaa Moubaraki Prof. Gopalan Rajaraman Prof. Keith S. Murray 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(16):4156-4165
We report four new complexes based on a {LnIII6} wheel structure, three of which possess a net toroidal magnetic moment. The four examples consist of {TbIII6} and {HoIII6} wheels, which are rare examples of non DyIII based complexes possessing a toroidal magnetic ground state, and a {DyIII6} complex which improves its toroidal structure upon lowering the crystallographic symmetry from trigonal (R ) to triclinic (P ). Notably the toroidal moment is lost for the trigonal {ErIII6} analogue. This suggests the possibility of utilizing the popular concept of oblate and prolate electron density of the ground state MJ levels of lanthanide ions to engineer toroidal moments. 相似文献