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Dinitrogen cleavage and hydrogenation to ammonia with a uranium complex

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National Science Review 2023年第2期10卷 165-173页

作者： Xiaoqing Xin Iskander Douair Yue Zhao Shuao Wang Laurent Maron Congqing Zhu State Key Laboratory of Coordination Chemistry Jiangsu Key Laboratory of Advanced Organic Materials School of Chemistry and Chemical EngineeringNanjing University School of Medicine and Holistic Integrative Medicine Nanjing University of Chinese Medicine lpcno CNRS and INSA Université Paul Sabatier State Key Laboratory of Radiation Medicine and Protection School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education InstitutionsSoochow University

The Haber-Bosch process produces ammonia(NH3) from dinitrogen(N2) and dihydrogen(H2),but re quires high temperature and pressure.Before iron-based catalysts were exploited in the current industrial Haber-Bosch process,uranium-based materials served as effective catalysts for production of NH3from N2.Although some molecular uranium complexes are known to be capable of combining with N2,further hydrogenation with H2forming NH3has not been reported to date.Here,we describe the first example of N2cleavage and hydrogenation with H2to NH3with a molecular uranium complex.The N2cleavage product contains three uranium centers that are bridged by three imido μ2-NH ligands and one nitridoμ3-N ligand.Labeling experiments with15N demonstrate that the nitrido ligand in the product originates from N2.Reaction of the N2-cleaved complex with H2or H+forms NH3under mild conditions.A synthetic cycle has been established by the reaction of the N2-cleaved complex with trimethylsilyl chloride.The isolation of this trinuclear imido-nitrido product implies that a multi-metallic uranium assembly plays an important role in the activation of N2.

关键词： N

Unusual selective reactivity of the rare-earth metal complexes bearing a ligand with multiple functionalities

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Science China Chemistry 2023年第1期66卷 117-126页

作者： Dongjing Hong Thayalan Rajeshkumar Shan Zhu Zeming Huang Shuangliu Zhou Xiancui Zhu Laurent Maron Shaowu Wang Key Laboratory of Functional Molecular Solids Ministry of EducationAnhui Laboratory of Molecule-Based MaterialsCollege of Chemistry and Materials ScienceAnhui Normal UniversityWuhu 241000China Anhui Laboratory of Clean Catalytic Engineering Anhui Laboratory of Functional Coordinated Complexes for Materials Chemistiry and ApplicationCollege of Chemical and Environmental EngineeringAnhui Polytechnic UniversityWuhu 241000China lpcno CNRS&INSAUniversite Paul Sabatier 135 Avenue de Rangueil31077 ToulouseFrance

Ligands play a key role in controlling activity of organometallic complexes so that development of new ligands to overcome the challenge is the main topic of modern chemistry.The first example of 1,1-hydride migratory insertion and intramolecular redox reaction has been realized in this work by applying a new ligand in rare-earth metal chemistry.The novel rare-earth metal complexes L^(Mes)RECH2TMS(THF)(RE=Y(1a),Dy(1b),Er(1c),Yb(1d),L^(Mes)=1-(3-(2,6-iPr_(2)C_(6)H_(3)N=CH)C8H4N)-CH_(2)CH_(2)-3-(2-CH2–4,6-Me_(2)C_(6)H_(2))-(N(CH)_(2)NC),THF=tetrahydrofuran)bearing a ligand with imino,indolyl,NHC(N-heterocyclic carbene)multiple functionalities were synthesized and characterized.Treatment of complexes 1 with silanes(PhSiH3or PhSiH2Me or PhSiD3)selectively produced the unprecedented 1,1-hydride(or deuterated H)migratory insertion of the indolyl moiety of the novel unsymmetrical dinuclear rare-earth metal complexes 2.The complex 2a reacts with Ph_(2)C=O to give the selective C=O double bond insertion to the RE–Co-methylene-Mesbond product 3a which further reacts with another Ph_(2)C=O(or DMAP,4-N,N-dimethylaminopyridine)affording the novelμ-η^(2):η^(3)-dianionic 3-iminoindolyl dinuclear rare-earth metal complex 4a.The latter is formed through an unusual intramolecular redox reaction(through electron migration from the 2-carbanion of the indolyl ring to the imino motif)resulting in the re-aromatization of the indolyl ring.

关键词： rare-earth metal complexes indole N-heterocyclic carbene Fischer-type carbene 1 1-migratory insertion dianionic 3-iminoindolyl

Insight of surface treatments for CMOS compatibility of InAs nanowi

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Nano Research 2019年第3期12卷 581-586页

作者： Daya S. Dhungana Anne Hemeryck Nicolo Sartori Pier-Francesco Fazzini Filadelfo Cristiano Sebastien R. Plissard CNRS LAAS-CNRS Universite de Toulouse F-31400 Toulouse France lpcno INSA Universite de Toulouse Toulouse France

A CMOS compatible process is prese nted in order to grow self-catalyzed InAs nano wires on silic on by molecular beam epitaxy. The crucial step of this process is a new in-situ surface preparation under hydrogen (gas or plasma) during the substrate degassing combined with an in-situ arsenic ann eali ng prior to growth. Morphological and structural characterizati ons of the InAs nano wires are prese nted and growth mecha nisms are discussed in detail. The major in flue nee of surface termi nation is exposed both experime ntally and theoretically using statistics on ensemble of nanowires and density functional theory (DFT) calculations. The differences observed between Molecular Beam Epitaxy (MBE) and Metal Organic Vapor Phase Epitaxy (MOVPE) growth of I nAs nano wires can be explai ned by these differe nt surfaces termi nations. The transition between a vapor solid (VS) and a vapor liquid solid (VLS) growth mechanism is presented. Optimized growth conditions lead to very high aspect ratio nano wires (up to 50 nm in diameter and 3 micron in len gth) without passi ng the 410℃ thermal limit, which makes the whole process CMOS compatible. Overall, our results suggest a new method for surface preparation and a possible tuning of the growth mechanism using different surface termi nations.

关键词： Ⅲ-Ⅴ semiconductors on silicon InAs nanowires self-catalyzed growth hydrogen preparation growth modeling density functional theory (DFT) modeling

Cotunneling transport in ultra-narrow gold nanowire bundles

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Nano Research 2013年第9期6卷 644-651页

作者： Anais Loubat Walter Escoffier Lise-Marie Lacroix Guillaume Viau Reasmey Tan Julian Carrey Benedicte Warot-Fonrose Bertrand Raquet Laboratoire National des Champs Magnetiques Intenses CNRS-INSA-UJF-UPS UPR3228 143 avenue de Rangueil F-31400 ToulouseFrance Universite de Toulouse INSA UPS LPCNO (Laboratoire de Physique et Chimie des Nano-Objets) F-31077 Toulouse France CNRS UMR5215 lpcno F-31077 Toulouse France Centre d'Elaboration de Materiaux et d'Etudes Structurales CNRS 29 rue Jeanne Marvig F-31077 Toulouse France

我们调查费用运输在拥挤不堪极端狭窄(1.5 nm 直径) 金 nanowires 由 oleylamine ligands 稳定了。我们给控告效果在的证据微弱地联合了一个维(1D ) nanowires，由温度和偏爱电压监视了。在低温度，在库仑封锁政体，当前的流动揭示在 Au... 详细信息

我们调查费用运输在拥挤不堪极端狭窄(1.5 nm 直径) 金 nanowires 由 oleylamine ligands 稳定了。我们给控告效果在的证据微弱地联合了一个维(1D ) nanowires，由温度和偏爱电压监视了。在低温度，在库仑封锁政体，当前的流动揭示在 Au-NWs 的 1D 片断之间的一个原来的合作多跳跃的过程，最小化收费精力费用。在库仑封锁阀值电压上面并且在高温度，费用运输演变为在 nearestnanowires 之间的顺序的通道政体。我们在捆内的 Au-NWs 的有效长度类似于电子波浪的 1D 本地化长度的分析表演工作(120 nm 的顺序吗？？

关键词：金纳米线黄金运输线束电荷传输库仑阻塞电子波函数电压监测

Are Sc-C and Sc-P Bonds Reactive in Scandium Phosphinoalkylidene Complex？ Insights on a Versatile Reactivity

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Chinese Journal of Chemistry 2018年第10期36卷 904-908页

作者： Weiqing Mao Li Xiang Carlos Alvarez Lamsfus Laurent Maron Xuebing Leng Yaofeng Chen State Key Laboratory of Organometallic Chemistry Center for Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry Univer- sity of Chinese Academy of Sciences Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 China lpcno CNRS & INSA Universite Paul Sabatier 135 Avenue de Rangueil 31077 Toulouse France

The peculiar electronic structure of scandium phosphinoalkylidene complex [LSc{C（SiMe3）PPh2}THF] （L=[MeC（NDIPP）CHC（NDIPP）Me]-）, DIPP= 2,6-（Pr）2C6H3） leads to an interesting versatile reactivity, which is demonstrated both experimentally and computationally. The complex undergoes [2＋2] cycloaddition reactions with alkynes, and easily activates various X-O bonds such as C-O of propylene oxide, N-O of 3,5-dimethylisoxazole, B-O of pinacolborane and Si-O of triethoxysilane. These reactions occur on the Sc-C bond of the phosphinoalkylidene complex. Interestingly, the Sc-P bond can also be activated as the presence of a Sc-C-P three center π interaction in the complex allows performing C-F activation of 2,6-difluoro- pyridine and 1,2 addition with imine or ketone. The complex also reacts with metal complexes, [（COD）RhCl]2 and （Ph3P）AuCl, to form structural intriguing heterobimetallic complexes.

关键词： alkylidene density functional calculations multiple bonds phosphorus scandium

Uranium(Ⅲ)–Phosphorus(Ⅲ) Synergistic Activation of White Phosphorus and Arsenic

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CCS Chemistry 2022年第8期4卷 2630-2638页

作者： Wei Fang Iskander Douair Adrian Hauser Kai Li Yue Zhao Peter WRoesky Shuao Wang Laurent Maron Congqing Zhu State Key Laboratory of Coordination Chemistry Jiangsu Key Laboratory of Advanced Organic MaterialsSchool of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023 lpcno CNRS&INSAUniversitéPaul SabatierToulouse 31077 Institute of Inorganic Chemistry Karlsruhe Institute of Technology(KIT)Karlsruhe 76131 State Key Laboratory of Radiation Medicine and Protection School for Radiological and Interdisciplinary Sciences(RAD-X)Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education InstitutionsSoochow UniversitySuzhou 215123

The study of small-molecule activation by f-block elements still lags far behind that of transition metals.Although a few uranium complexes have been reported to activate dinitrogen,reports on the activation of heavier congeners,such as white phosphorus(P_(4)),by uranium species are extremely rare,and no example of uranium-mediated activation of elemental arsenic has appeared.

关键词： uranium As0 nanoparticle white phosphorus small molecule activation U(Ⅲ)–P(Ⅲ)synergy density functional theory calculations

Spin Dynamics in (111) GaAs/AlGaAs Undoped Asymmetric Quantum Wells

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Chinese Physics Letters 2012年第9期29卷 159-161页

作者：王刚叶慧琪石震武王文新 MARIE Xavier BALOCCHI Andrea AMAND Thierry 刘宝利 Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190 Universitéde Toulouse INSA-CNRS-UPSLPCNO135 avenue de Rangueil31077 ToulouseFrance

The electron spin dynamics is investigated by the time-resolved Kerr rotation technique in a pair of special GaAs/AlGaAs asymmetric quantum well samples grown on(111)-oriented substrates,whose structures are the same except for their opposite directions of potential asymmetry.A large difference of spin lifetimes between the two samples is observed at low temperature.This difference is interpreted in terms of a cancellation effect between the Dresselhaus spin-splitting term in the conduction band and another term induced by interface inversion asymmetry.The deviation decreases with the increasing temperature,and almost disappears when T>100 K because the cubic Dresselhaus term becomes more important.

关键词： Quantum conduction directions

Localized magnetization reversal processes in cobalt nanorods with different aspect ratios

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Nano Research 2015年第7期8卷 2231-2241页

作者： Marc Pousthomis Evangelia Anagnostopoulou Ioannis Panagiotopoulos Rym Boubekri Weiqing Fang Frederic Ott Kahina Ait Atmane Jean-Yves Piquemal Lise-Marie Lacroix Guillaume Viau Universite de Toulouse LPCNO UMR 5215 INSA CNRS UPS 135 av de Rangueil 31077 Toulouse Cedex 4 France Laboratoire Leon Brillouin CEA/CNRS UMR 12 IRAMIS CEA-Saclay 91191 Gifsur Yvette France Department of Materials Science and Engineering University ofloannina Ioannina 45110 Greece Universite Paris Diderot Sorbonne Paris Cite ITODYS CNRS UMR 7086 15 rueJ.-A de Baif 75205 Paris Cedex 13 France

We present results of the synthesis of cobalt nanorods using the polyol process and the mechanism of magnetization reversal. We show that the nucleation step is significantly dependent on the nature of the ruthenium chloride used as the nucleating agent. This allows varying the diameter and aspect ratio of the cobalt nanorods independently. Co nanorods with aspect ratio, mean diameter, and mean length in the ranges ARm =3-16, Din= 7-25 nm, and Lm=30-300 nm, respectively, were produced using this method. X-ray diffraction and electron microscopy showed that a strong discrepancy between the structural coherence and morphological aspect ratio can exist because of stacking faults. The coercivity of assemblies of different nanorods was systematically measured, and the highest values were obtained for the smallest diameter and the largest structural coherence length. Micromagnetic simulations were performed to account for the dependence of the coercive field on the diameter. An important observation is that simple coherent magnetization rotation models do not apply to these magnetic nano-objects. Even for very small diameters （Dm = 5-10 nm） well below the theoretical coherent diameter Dcoh（CO）= 24 nm, we observed inhomogeneous reversal modes dominated by nucleation at the rod edges or at structural defects such as stacking faults. We conclude that, in order to produce high-coercivity materials based on nanowires, moderate aspect ratios of 5-10 are sufficient for providing a structural coherence similar to the morphological aspect ratio. Thus, the first priority should be to avoid the formation of stacking faults within the Co nanowires.

关键词： nanorod nanowire permanent magnets micromagnetic calculations shape anisoteopy