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Multiply Charged Anions,Maximum Charge Acceptance,and Higher Electron Affinities of Molecules,Superatoms,and Clusters

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物理化学学报 2018年第6期34卷 675-682页

作者： VON SZENTPáLY László Institut fur Theoretische chemie Universitat Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany.

The addition of electrons to form gas-phase multiply charged anions(MCAs)normally requires sophisticated experiments or *** this work,the factors stabilizing the MCAs,the maximum electron uptake of gas-phase molecules,X,and the electronic stability of MCAs X^(Q-),are *** drawbacks encountered when applying computational and/or conceptual density functional theory(DFT)to MCAs are *** develop and test a different model based on the valence-state *** in DFT,the electronic energy,E(N,v_(ex)),is a continuous function of the average electron number,N,and the external potential,v_(ex),of the *** valence-state-parabola is a second-order polynomial that allows extending E(N,v_(ex))to dianions and higher *** model expresses the maximum electron acceptance,Q_(max),and the higher electron affinities,A_Q,as simple functions of the firstelectron affinity,A_1,and the ionization energy,I,of the"ancestor"***,the maximum electron acceptance is Q_(max,calc)=1+12A_1/7(I-A_1).The ground-state parabola model of the conceptual DFT yields approximately half of this value,and it is termed Q_(max,GS)=?+A_1/(I-A_1).A large variety of molecules are evaluated including fullerenes,metal clusters,super-pnictogens,super-halogens(OF_3),super-alkali species(OLi_3),and neutral or charged transition-metal complexes,AB_(m )L_n^(0/+/-).The calculated second electron affinity A_(2,calc)=A_1-(7/12)(I-A_1)is linearly correlated to the literature references A_(2,lit) with a correlation coefficient R=0.998.A_2 or A_3 values are predicted for further 24 *** appearance sizes,n_(ap)^(3-),of triply charged anionic clusters and fullerenes are calculated in agreement with the literature.

关键词： Multiply charged negative ions Their appearance sizes Second electron affinity Third electronaffinity Conceptual density-functional theory Valence-state parabola model of electronegativity

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Porous silicon/carbon composites as anodes for high-performance lithium-ion batteries

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新型炭材料（中英文） 2024年第5期39卷 992-1002页

作者： TIAN Zhen-yu WANG Ya-fei QIN Xin Shaislamov Ulugbek Hojamberdiev Mirabbos ZHENG Tong-hui DONG Shuo ZHANG Xing-hao KONG De-bin ZHI Lin-jie School of Materials Science and Engineering China University of Petroleum(East China)Qingdao 266580China College of New Energy China University of Petroleum(East China)Qingdao 266580China Center for Development of Nanotechnology at the National University of Uzbekistan Tashkent 100174Uzbekistan Department of Physics National University of UzbekistanTashkent 100174Uzbekistan Institut für chemie Technische Universität BerlinBerlin 10623Germany Advanced Chemical Engineering and Energy Materials Research Center China University of Petroleum(East China)Qingdao 266580China

Silicon anodes are promising for use in lithium-ion ***,their practical application is severely limited by their large volume expansion leading to irreversible material fracture and electrical *** study proposes a new top-down strategy for preparing microsize porous silicon and introduces polyacrylonitrile(PAN)for a nitrogen-doped carbon coating,which is designed to maintain the internal pore volume and lower the expansion of the anode during lithiation and *** then explore the effect of temperature on the evolution of the structure of PAN and the electrochemical behavior of the composite *** treatment at 400℃,the PAN coating retains a high nitrogen content of 11.35 at%,confirming the presence of C—N and C—O bonds that improve the ionic-electronic transport *** treatment not only results in a more intact carbon layer structure,but also introduces carbon defects,and produces a material that has remarkable stable cycling even at high *** cycled at 4 A g^(-1),the anode had a specific capacity of 857.6 mAh g^(-1) even after 200 cycles,demonstrating great potential for high-capacity energy storage applications.

关键词： Porous silicon Lithium-ion batteries Polyacrylonitrile Electrochemical behavior

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Gαq,Gγ1 and Plc21C Control Drosophila Body Fat Storage

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Journal of Genetics and Genomics 2014年第5期41卷 283-292页

作者： Jens Baumbach Yanjun Xu Philip Hehlert Ronald P.Khnlein Abteilung Molekulare Entwicklungsbiologie Forschungsgruppe Molekulare Physiologie Max-Planck-Institut fr biophysikalische Chemie Abteilung Molekulare Entwicklungsbiologie Forschungsgruppe Molekulare PhysiologieMax-Planck-Institut fr biophysikalische Chemie

mobilization of body fat is essential for energy homeostasis in animals. In insects, the adipokinetic hormone （Akh） systemically controls body fat mobilization. Biochemical evidence supports that Akh signals via a G protein-coupled receptor （GPCR） called Akh receptor （AkhR） using cyclic-AMP （cAMP） and Ca2＋ second messengers to induce storage lipid release from fat body cells. Recently, we provided genetic evidence that the intracellular calcium （iCa2＋） level in fat storage cells controls adiposity in the fruit fly Drosophila melanogaster. However, little is known about the genes, which mediate Akh signalling downstream of the AkhR to regulate changes in iCa2＋. Here, we used thermogenetics to provide in vivo evidence that the GPCR signal transducers G protein α q subunit （Gαq）, G protein γ1 （Gγ1） and Phospholipase C at 21C （Plc21C） control cellular and organismal fat storage in Drosophila. Transgenic modulation of Gαq, Gγ1 and Plc21C affected the iCa2＋ of fat body cells and the expression profile of the lipid metabolism effector genes midway and brummer, which results in severely obese or lean flies. Moreover, functional impairment of Gαq, Gγ1 and Plc21C antagonised Akh-induced fat depletion. This study characterizes Gαq, Gγ1 and Plc21C as anti-obesity genes and supports the model that Akh employs the Gαq/Gγ1/Plc21C module of iCa2＋ control to regulate lipid mobilization in adult Drosophila.

关键词： Plc21C Gαq Gγ1 Calcium Fat storage Adipokinetic hormone

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Catalytic enantioselective synthesis of β-amino alcohols by nitrene insertion

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Science China Chemistry 2021年第3期64卷 452-458页

作者： Zijun Zhou Yuqi Tan Xiang Shen Sergei Ivlev Eric Meggers Fachbereich chemie Philipps-Universitat MarburgHans-Meerwein-Strasse 435043 MarburgGermany

Chiral β-amino alcohols are important building blocks for the synthesis of drugs, natural products, chiral auxiliaries, chiral ligands and chiral organocatalysts. The catalytic asymmetric β-amination of alcohols offers a direct strategy to access this class of molecules. Herein, we report a general intramolecular C(sp^(3))–H nitrene insertion method for the synthesis of chiral oxazolidin-2-ones as precursors of chiral β-amino alcohols. Specifically, the ring-closing C(sp^(3))–H amination of N-benzoyloxycarbamates with 2 mol% of a chiral ruthenium catalyst provides cyclic carbamates in up to 99% yield and with up to 99% *** method is applicable to benzylic, allylic, and propargylic C–H bonds and can even be applied to completely non-activated C(sp^(3))–H bonds, although with somewhat reduced yields and stereoselectivities. The obtained cyclic carbamates can subsequently be hydrolyzed to obtain chiral β-amino alcohols. The method is very practical as the catalyst can be easily synthesized on a gram scale and can be recycled after the reaction for further use. The synthetic value of the new method is demonstrated with the asymmetric synthesis of a chiral oxazolidin-2-one as intermediate for the synthesis of the natural product aurantioclavine and chiral β-amino alcohols that are intermediates for the synthesis of chiral amino acids, indane-derived chiral Box-ligands, and the natural products dihydrohamacanthin A and dragmacidin A.

关键词： asymmetric catalysis nitrene amination chiral-at-metal ruthenium

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CONTACT MATERIALS FOR GaSb AND InSb: A PHASE DIAGRAM APPROACH

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Acta Metallurgica Sinica(English Letters) 2002年第2期15卷 143-148页

作者： K. W. Richter and H. Ipser Institut für anorganische chemie, Universit?t Wien W?hringerstrasse 42, A-1090 Vienna, Austria Inst. fur Anorganische chemie Univ. Wien Wahringerstrasse 42 A-1090 Vienna Austria

The development of well defined and thermally stable ohmic contacts for Ⅲ- Ⅴ semi-conductors like InSb and GaSb is still a challenging problem in semiconductor devicetechnology. As device processing usually includes the exposure to elevated tempera-tures, interface reactions often occur during metallization and further heat *** is thus important to understand the respective phase equilibria of the involved el-ements. From the thermodynamic point of view, binary and ternary compounds inequilibrium with the respective compound semiconductor would be the best choice forcontact materials as these contacts will be stable even after long exposure to elevatedtemperatures. These possible candidates for contact materials may be directly obtainedfrom the phase *** the last years we investigated several phase diagrams of transition metals withGaSb and InSb. Experimental results in the systems Ga-Ni-Sb, Ga-Pd-Sb, Ga-Pt-Sb,In-Ni-Sb and In-Pd-Sb are summarized and are discussed in the context of contactchemistry.

关键词： contact material phase diagram GaSb InSb

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Enantioselective and Enantioconvergent Iron-Catalyzed C(sp^(3))-H Aminations to Chiral 2-Imidazolidinones

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Chinese Journal of Chemistry 2023年第17期41卷 2065-2070页

作者： Tianjiao Cui Chen-Xi Ye Jordan Thelemann Daniel Jenisch Eric Meggers Fachbereich chemie Philipps-Universitat MarburgHans-Meerwein-Strasse 435043MarburgGermany

Comprehensive Summary Enantioselective or enantioconvergent iron-catalyzed ring-closing C(sp^(3))-H aminations of N-aroyloxyurea through intermediate iron nitrene species provide chiral 2-imidazolidinones in up to 99%yield and with up to 95%ee(40 examples).This is a rare example in which sustainable iron catalysis is combined with C(sp^(3))-H amination and asymmetric catalysis.

关键词： Iron Asymmetric catalysis C-H activation Amination Nitrenes Heterocycles

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An inverted triplesalen ligand by a convergent synthesis and its influence on trinuclear Fe_3~Ⅲ complexes

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Science China Chemistry 2012年第6期55卷 951-966页

作者： FELDSCHER Bastian KRICKEMEYER Erich MOSELAGE Marc THEIL Hubert HOEKE Veronika KAISER Yvonne STAMMLER Anja BGGE Hartmut GLASER Thorsten Lehrstuhl für Anorganische chemie I Fakultt für Chemie Universitt Bielefeld Universittsstr. 25 D-33615 Bielefeld Germany

The inverted triplesalen ligand H6feldMe has been synthesized from 2,4,6-triformyl-phloroglucinol and a ketimine salen half-unit in a convergent synthesis. NMR, IR, and UV-vis spectroscopy reveal that this ligand is not in the O-protonated tau- tomer but in the N-protonated tautomer with substantial heteroradialene contribution. This ligand and the conventional triple- salen ligand H6talent-au2 have been used to synthesize the trinuclear Fem complexes [（feldMe）（FeCl）3] and [（talent-Bu2）（FeC1）3], respectively. The molecular structures of these complexes were obtained by single-crystal X-ray diffraction. Two trinuclear Fem complexes of [（feldMe）（FeCl）3] dimerize via two Fe-phenolate bonds, whereas due to steric hindrance no dimerization is observed for [（talent-Bu2）（FeC1）3]. The structural data also reveal some heteroradialene contribution in the trinuclear complexes. Whereas UV-vis and MOlSbauer spectroscopy are not suitable to distinguish between the two complexes, FT-IR spectra show characteristic features due to the different substitution patterns of the conventional and the inverted triplesalen ligands. Another handle is provided by electrochemistry. Whereas both complexes exhibit an irreversible oxidation wave （0.94 V vs. Fc＋/Fc for [（feldMe）（FeC1）3] and 0.84 V vs. Fc~/Fc for [（talent-Bu2）（FeC1）3]）, which is assigned to the oxidation of the central backbone, higher potential oxidations are reversible for [（talent-Bu2）（FeC1）3]） but irreversible for [（feldMe）（FeC1）3]. This is attributed to the reversible oxidation of the terminal phenolates in the di-tert-butyl substituted [（talentBu2）（FeCl）3] in contrast to the mono-methyl-substituted phenolates in [（feld^ae）（FeC1）3]. The magnetic properties of [（talen^-Bu2）（FeC1）3] reveal a very small ferromagnetic coupling with significant zero-field splitting of the Feul S = 5/2 ions. In contrast, the dimerization of two trinu- clear complexes in [（feldMe）（FeCl）3] results in antiferromagnetic interactions between the two pheno

关键词： magnetic properties iron complexes spin-polarization triplesalen

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Orbital deletion procedure and its applications

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Science China Chemistry 1999年第3期42卷 253-260页

作者：莫亦荣林梦海吴玮张乾二 Department of Chemistry Institute of Physical Chemistry and State Key Laboratory for Physical Chemistry on Solid Surface Xiaman University Xiamen China Computer chemie Centrum Institut für Organische Chemie Universität Erlangen-Nürnberg Erlangen Germany

The orbital deletion procedure is introduced, which is suited to quantitatively investigating the electronic delocalization effect in carbocations and boranes. While the routineab initio molecular orbital methods can generate wavefunctions for real systems where all electrons are delocalized, the present orbital deletion procedure can generate wavefunctions for hypothetical reference molecules where electronic delocalization effect is deactivated. The latter wave-function normally corresponds to the most stable resonance structure in terms of the resonance theory. By comparing and analyzing the delocalized and the localized wavefunctions, one can obtain a quantitative and instinct picture to show how electronic delocalization inside a molecule affects the molecular structure, energy as well as other physical properties. Two examples are detailedly discussed. The first is related to the hyperconjugation of alkyl groups in carbocations and a comparison of the order of stability of carbocations is made. The second concerns the Lewis acidity of boron trihalides where the conjugation effect among the doubly-occupied π atomic orbitals on the halide atoms and the vacant π atomic rbital on the boron atom plays a dominant role in determining the relative acceptor properties. The results demonstrate that the orbital deletion procedure can be used to very successfully interpret some traditional chemical intuitions and concepts in a quantitative way.

关键词： electronic delocalization orbital deletion procedure carbocation boron trihalide.

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Cathodic activated stainless steel mesh as a highly active electrocatalyst for the oxygen evolution reaction with self-healing possibility

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Journal of Energy Chemistry 2020年第10期29卷 153-160页

作者： Gui-Rong Zhang Liu-Liu Shen Patrick Schmatz Konrad Krois Bastian J.M.Etzold Ernst-Berl-Institut für Technische und Makromolekulare chemie Technische Universit鋞Darmstadt64287 DarmstadtGermany

The oxygen evolution reaction(OER)represents one of the major bottlenecks for broad-based applications of many clean energy storage/conversion *** key to solving this problem lies in developing high-performing,cost effective and stable catalysts for the ***,we demonstrate that ubiquitous stainless steel mesh(SSM)materials activated by a facile cathodization treatment can be employed as a high performing OER catalyst,as showcased by the impressively low overpotentials of 275 and 319 mV to reach the benchmark current densities of 10 and 100 mA cm^−2(1.0 M KOH),*** SSM also exhibits excellent performance in a two-electrode water electrolyzer,which requires a low cell voltage of 1.58 at 10 mA cm^−2 and outperforms many of water electrolyzers using earth-abundant OER ***,cathodized SSM with minor performance degradation after the stability test can also be readily healed by subjecting it to an additional cathodization *** is disclosed that the superior performance of cathodized SSMs stems from the surface enrichment of OER active Ni(oxy)hydroxide,facile gas-bubble removal and transportation over the unique mesh-structured surfaces,while the abundant reservoir of nickel in the bulk allows healing of the catalyst by a facile cathodization.

关键词： Oxygen evolution reaction Water splitting Stainless steel mesh Cathodization Mass transfer limitation Self-healing

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High-dimensional neural network potentials for magnetic systems using spin-dependent atom-centered symmetry functions

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npj Computational Materials 2021年第1期7卷 1541-1551页

作者： Marco Eckhoff Jörg Behler Universität Göttingen Institut für Physikalische ChemieTheoretische ChemieTammannstrasse 637077 GöttingenGermany Universität Göttingen International Center for Advanced Studies of Energy Conversion(ICASEC)Tammannstrasse 637077 GöttingenGermany

Machine learning potentials have emerged as a powerful tool to extend the time and length scales of first-principles quality ***,most machine learning potentials cannot distinguish different electronic spin arrangements and thus are not applicable to materials in different magnetic *** we propose spin-dependent atom-centered symmetry functions as a type of descriptor taking the atomic spin degrees of freedom into *** used as an input for a high-dimensional neural network potential(HDNNP),accurate potential energy surfaces of multicomponent systems can be constructed,describing multiple collinear magnetic *** demonstrate the performance of these magnetic HDNNPs for the case of manganese oxide,*** method predicts the magnetically distorted rhombohedral structure in excellent agreement with density functional theory and *** efficiency allows to determine the Néel temperature considering structural fluctuations,entropic effects,and *** method is general and is expected to be useful also for other types of systems such as oligonuclear transition metal complexes.

关键词： magnetic symmetry neural

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