Syntheses,Structures,Fluorescence and Heterogeneous Catalysis of Coordination Polymers with 4-Benzoimidazol-1-yl-methyl Benzoic Acid and 2,2′-Dipyridine

Two coordination polymers called [Ni（L）2]n（1） and [Ni（2,2？-bpy）22（H2O）]n （2）（HL = 4-benzoimidazol-1-yl-methyl benzoic acid, 2,2？-bpy = 2,2＇-dipyridine） were synthesized by solvothermal reaction simultaneously and characterized by elemental analyses, thermogravimetric analysis, X-ray powder diffraction, IR spectroscopy and single-crystal X-ray diffraction analysis. Complex 1 crystallizes in monoclinic system, space group P21/c with a = 14.673（3）, b = 10.773（2）, c = 16.566（3） ？, V = 2559.2（8） A^3, Z = 4 and F（000） = 1160. 2 also crystallizes in monoclinic system, space group C2/c with a = 15.404（3）, b = 12.652（3）, c = 6.5362（13） ？, V = 1246.2（5） A^3, Z = 4 and F（000） = 712. The bridging L ligand connects the Ni^Ⅱ cations into a 2D network in complex 1, while 2 shows a 1D structure formed through the two O atoms of SO4^（2-） ions connecting the molecule. The catalytic properties indicate that complex 1 shows good catalytic activities for the cyanosilylation of 4-chlorobenzaldehyde. In addition, fluorescence property of complex 1 which quenches the excitation intensity in solid state was investigated at room temperature.

SIMULTANEOUS POLYMERIZATION AND FORMATION OF POLYPHENYLACETYLENE FILMS BY RARE-EARTH COORDINATION CATALYSIS Ⅳ.KINETICS AND MECHANISM OF POLYMERIZATION

The CO_2 quenching method has been used for the first time to determine the active complex concen- tration in Nd(naph)_3-Al(i-Bu)_3 catalyst system for polymerization of phenylacetylene into polyphenylacetylene(PPA)films.The kinetics and mechanism of this polymerization have been investigated by CO_2 quenching and IR,UV analytical methods.The kinetic equation can be expressed as Rp=k[M][Cp],and the apparent activation energy is about 13.6 kJ/mol.There is self-termination of chain propagating.Models for formation of the active complex and polymerization mechanism are proposed.

Coordinatively unsaturated sites in zeolite matrix: Construction and catalysis

Zeolites with ordered porous structure of molecular size are widely employed as commercial adsorbents and catalysts.On the other hand,the zeolite matrix is regarded as an ideal scaffold for hosting coordinatively unsaturated sites.Remarkable achievements have been made dealing with the construction,characterization and catalytic applications of coordinatively unsaturated sites in zeolite matrix.Herein,a literature overview of recent progresses on this important topic is presented from the specific view of coordination chemistry.Different strategies to construction coordinatively unsaturated sites in zeolite matrix,in zeolite framework or extraframework positions,are first introduced and their characteristics are compared.Then,spectroscopic techniques to determine the existing states of cation sites and their transformations in zeolite matrix are discussed.In the last section,the catalytic applications of coordinatively unsaturated sites in zeolite matrix for various important chemical transformations are summarized.

Importance, features and uses of metal oxide catalysts in heterogeneous catalysis

This short review paper aims at assembling the present state of the art of the multiuses of metal oxides in heterogeneous catalysis, concerning liquid and gaseous phases of the reactant mixtures on solid catalysts. It includes the description of the main types of metal oxide catalysts, of their various preparation procedures and of the main reactions catalysed by them (acid-base type, selective and total oxidations, bi-functional catalysis, photocatalysis, biomass treatments, environmental catalysis and some of the numerous industrial applications). Challenges and prospectives are also discussed.

Coordination environment of active sites and their effect on catalytic performance of heterogeneous catalysts

The structural complexity of supported metal catalysts,playing significant role in a wide range of chemical technologies,have prevented us from deeply understanding their catalytic mechanisms at atomic level.A fundamental understanding of the nature of active sites and structure–performance relationship of supported metal catalysts from a comprehensive view will open up numerous new opportunities for the development of advanced catalysts to address the global challenges in energy conversion and environmental protection.This review surveys the effects of multiple factors,including the metal size,shape,support,alloy and ligand modifier,on the coordinated environment of active center and further their influence on the catalytic reactions,aiming to provide guidance for the design of industrialized heterogeneous catalysts with extraordinary performance.Subsequently,the key structure characterization techniques in determining the coordination structure of active metal sites,especially the dynamic coordination structure change under the reaction condition,are well summarized.A brief summary is finally provided together with personal perspectives on the further development in the field of heterogeneous metal catalysts.

In situ spectroscopic insights into the redox and acid-base properties of ceria catalysts

Cerium oxide(ceria)plays an important and fascinating role in heterogeneous catalysis as illustrated by its versatile use as a catalyst,a catalyst support,or a promotor in various oxidation and reduction reactions.Central to these reactions is the rich defect chemistry,facile redox capability,and unusual acid-base properties of ceria.Understanding the unique redox and acid-base properties of ceria is essential to build the structure-catalysis relationship so that improved catalytic functions can be achieved for ceria-based materials.Among the characterization toolbox,spectroscopic approach indisputably stands out for its unparalleled power in offering chemical insights into the surface properties of ceria at atomic and molecular level.In this review,we summarize advances in revealing the redox and acid-base properties of ceria via a variety of spectroscopic methods including optical,X-ray,neutron,electronic and nuclear spectroscopy.Both direct spectroscopy characterization and its coupling with probe molecules are analyzed to illustrate how the nature,strength and density of different surface sites are influenced by the pretreatment,the morphology and size of ceria nanoparticles.Further directions in taking advantage of in situ/operando spectroscopy for better understanding the catalysis of ceria-based materials are proposed in the summary and outlook section.

A N-tripodal Ligand Cu-Based Coordination Polymer with Good Catalytic Activity for the Reduction of 4-Nitrophenol

A complex {[Cu（tib）2（H2O）2]·（NO3）2}n（1） has been synthesized under N,N-dimethylacetamide（DMA） and water conditions. The structure of complex 1 was characterized by single-crystal X-ray crystallography. It crystallizes in monoclinic, space group P21/n with a = 10.6273（7）, b = 11.4184（7）, c = 13.4215（8） A, β = 108.290（2）°, V = 1546.38（17）A3, Z = 2, F（000） = 798, Dc = 1.667 g/cm3 and m = 0.786 mm-1） Complex 1 exhibits a 3D network due to the existence of O–H…O interaction between coordinated water and nitrate anions. Furthermore, complex 1 has a good catalytic activity for the reduction of 4-nitrophenol in Na BH4 solution.

Acid-base cooperativity of heterogeneous catalyst containing acidic framework and sterically hindered base for aldol condensation

A bifunctional heterogeneous catalyst containing two mutually incompatible acidic and basic sites, which exhibits cooperative catalytic behavior in the aldol condensation of acetone and various aldehydes, was synthesized by postgrafting of 1,5,7- triazabicyclo[4.4.0] dec-5-ene （TBD, a sterically hindered organic base） onto AI-MCM-41 molecular sieve. 2009 Xiao Bing Lu. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

Surface Coordination Decouples Hydrogenation Catalysis on Supported Metal Catalysts

Supported metal catalysts integrating advantages of catalytic hydrogenation and stoichiometric reduction are highly desirable for the green production of fine chemicals.Decoupling catalytic hydrogenation into H_(2)activation and selective reduction taking place at different locations is expected to provide an effective strategy to fabricate such catalyst systems.Herein,we report a decoupled hydrogenation system by modifying Pt catalysts supported on reducible In2O3 with ethylenediamine(EDA).The system exhibits good catalytic performance in oximes production from nitroalkanes,an industrially important reaction,by employing H_(2).Systematic studies demonstrate that the surface coordination of EDA on Pt is crucial to passivate the Pt surface from nitro hydrogenation without inhibiting H_(2)activation.The activated H_(2)species can then transfer and reduce the In_(2)O_(3)support in situ to generate sustainable stoichiometric reducing agents for the chemoselective reduction of nitroalkanes.Based upon the mechanistic understanding,a sustainable strategy for the production of oximes has been successfully fabricated.

A critical assessment of the roles of water molecules and solvated ions in acid-base-catalyzed reactions at solid-water interfaces

Solid-aqueous interfaces and phenomena occurring at those interfaces are ubiquitously found in a plethora of chemical systems.When it comes to heterogeneous catalysis,however,our understanding of chemical transformations at solid-aqueous interfaces is relatively limited and primitive.This review phenomenologically describes a selection of water-engendered effects on the catalytic behavior for several prototypical acid-base-catalyzed reactions over solid catalysts,and critically assesses the general and special roles of water molecules,structural moieties derived from water,and ionic species that are dissolved in it,with an aim to extract novel concepts and principles that underpin heterogeneous acid-base catalysis in the aqueous phase.For alcohol dehydration catalyzed by solid Bronsted acids,rate inhibition by water is most typically related to the decrease in the acid strength and/or the preferential solvation of adsorbed species over the transition state as water molecules progressively solvate the acid site and form extended networks wherein protons are mobilized.Water also inhibits dehydration kinetics over most Lewis acid-base catalysts by competitive adsorption,but a few scattered reports reveal substantial rate enhancements due to the conversion of Lewis acid sites to Brønsted acid sites with higher catalytic activities upon the introduction of water.For aldol condensation on catalysts exposing Lewis acid-base pairs,the addition of water is generally observed to enhance the rate when C–C coupling is rate-limiting,but may result in rate inhibition by site-blocking when the initial unimolecular deprotonation is rate-limiting.Water can also promote aldol condensation on Brønsted acidic catalysts by facilitating inter-site communication between acid sites through hydrogen-bonding interactions.For metallozeolite-catalyzed sugar isomerization in aqueous media,the nucleation and networking of intrapore waters regulated by hydrophilic entities causes characteristic enthalpy-entropy tradeoffs as these water moieties interact with kinetically relevant hydride transfer transition states.The discussed examples collectively highlight the utmost importance of hydrogen-bonding interactions and ionization of covalently bonded surface moieties as the main factors underlying the uniqueness of water-mediated interfacial acid-base chemistries and the associated solvation effects in the aqueous phase or in the presence of water.A perspective is also provided for future research in this vibrant field.

Design and synthesis of chiral Ti-1,1′-bi-2-naphthol coordination polymers for heterogeneous catalytic asymmetric oxidation of sulfides

Polymer-immobilized catalysis has many advantages such as easy recovery and reuse of catalyst. We prepared three novel chiral 1,1＇-bi-2-naphthol-Ti coordination polymers with properly designed ligands and Ti（O^ipr）4 under mild conditions. The prepared polymers exhibited good activity and excellent enantioselectivity （over 99%ee） in catalyzing the asymmetric oxidation of sulfides. The bridge linker in the polymer and the reaction solvent noticeably affected the enantioseleetivity. The chiral coordination polymer was very stable and easy to separate from catalyzed reaction systems, with no significant loss of activity or enantioselectivity after reuse for at least ten times. These findings suggest a promising type of catalysts for synthesizing the widely used sulfoxides by asymmetrically oxidizing sulfides.

D-band center coordination modulated enzyme-like activity in Fe-Cu dual-metal single-atom nanozymes

After explorations in a diversity of single-atom nanozymes(SAzymes),developing dual-centered SAzymes becomes a promising approach for superior catalytic performance.But confusing mechanisms including atomic coordination,spatial configuration,and metal–metal atom interaction hinder the development and design of SAzymes.Herein,a dual-centered Fe-Cu-N_(x)SAzyme exhibits excellent peroxidase(POD)-and catalase(CAT)-like activities with d-band center(ε_(d))coordination of Fe and Cu in multiple reaction stages,which plays a critical role in the adsorption of H_(2)O_(2)molecule and H_(2)O and O_(2)release.Therefore,the dband center coordination,which can be represented byε_(d)(Fe)–ε_(d)(Cu)shifts,leads to the competition between one-side and bilateral adsorption,which determines the favorable reaction path with lower energy barriers.Based on experimental statistics,simulated formation energies,and reaction barriers,3 configurations,Fe-Cu-N6-I,Fe-Cu-N_(8)-II,and Fe-Cu-N_(8)-III,are modeled and validated.Impressively,configuration-dependent catalytic selectivity and the competition between one-side and bilateral adsorption can be unveiled by d-band center coordination paradigm analysis.Theoretical simulations suggest that the unsymmetrical charge distribution over the three Fe-Cu configurations could tune the adsorption strength compared with the counterparts FeN_(4)and CuN_(4).The present work provides a potential route for optimizing enzyme-like catalysis by designing the dual-or even triple-metal SAzymes,which demonstrates the large space to modulate the metal atomic configuration and interaction.

双金属氰化物催化剂的制备、表征及其催化性能

以丙烯酸-异戊烯醇聚氧乙烯醚梳型共聚物为分散剂,通过分散聚合制备了高活性的双金属氰化物催化剂。元素分析和红外光谱证实了分散剂不仅起分散稳定作用,也参与了催化剂化学结构的形成。X射线衍射谱图和热失重分析说明分散剂与中心金属离子发生了直接络合作用,晶型发生畸变,趋向于无定形态。扫描电镜进一步表明分散法制备的催化剂整体尺寸明显小于直接沉淀法,形貌由紧密的片层状结构转变成更松散的无序堆积。得益于催化剂比表面积增加和单位面积上活性位点的增多,分散法制备的双金属氰化物的催化活性高达66585 g/g催化剂,远高于直接沉淀法(8245 g/g催化剂)。循环实验显示分散法制备的催化剂具有较好的循环能力,在第五次循环时催化活性仍能达56997 g/g催化剂(85.6%),远高于直接沉淀法的1501 g/g催化剂(18.2%)。

Acid-base Vapor Sensing Enabled by ESIPT-attributed Cd(II) Coordination Polymer with Switchable Luminescence

Fluorescence materials based on excited state intramolecular proton transfer(ESIPT)have attracted great attentiori due to the unique four-level energy states.Herein,we report the assembly of a Cd-LF coordination polymer from purposely designed LF(H2hpi2cf)ligand,which can present switchable luminescence behavior by gain or loss protons originated in uncoordinated ESIPT sites and serve as acid-base vapor sensors.Fabricated into in-situ grown film or transparent ink by simple methods,Cd-LF presents facile and portable amine sensor for food spoilage detection and fluorescent anti-counterfeiting ink applications.

Precise Assembly and Supramolecular Catalysis of Tetragonal-and Trigonal-Elongated Octahedral Coordination Containers

The construction of distorted or irregular coordination polyhedrons with specific shapes and functionalities is highly challenging.Here,we demonstrate a viable strategy for attaining a severely distorted octahedral coordination container through precise geometrical manipulation of its nanocavity along the C_(3) or C4 axis to turn on its supramolecular catalysis.We constructed a tetragonal-elongated octahedral coordination container utilizing sulfonylcalix[4]arene-capped Co4 units as six vertexes and tetragonalelongated from single-arm lengthened 5-[(4-carboxybenzyl)amino]isophthalate(L)as eight triangular faces.Through the concomitant introduction of C_(3)-symmetry cyclohexane-1,3,5-tricarboxylate as a secondary linker to construct two equilateral triangular base surfaces and L to build six isosceles triangular side planes,trigonal antiprismatic architecture(trigonal-elongated octahedron)was attained.The elongated octahedral containers exhibited distinctly higher binding capacity and stronger binding affinity toward reaction substrates than that of regular octahedral containers;thus,promoting geometry-dependent catalytic reactivity.Our geometrical manipulation strategy provides a viable approach for the convenient design of metal–organic materials with specific functionalities.

含能配位聚合物[Co_(4)(HBTI)_(4)(H_(2)O)_(8)]的合成、结构、爆轰性能及催化性质

我们以4,5‐双四唑咪唑(H3BTI)为能量配体,利用水热法构筑了一例新型含能配合物[Co_(4)(HBTI)_(4)(H_(2)O)_(8)](1)。晶体结构测定表明配合物1呈中心对称的四核结构,中心离子Co(Ⅱ)呈六配位的八面体几何构型。此外,结合Kissinger和Ozawa‐Doyle两种方法对1进行非等温热动力学分析,并基于密度泛函理论计算出1的爆轰性能相关参数。配合物1的摩擦感度高于360 N,且撞击感度高于40 J。配合物1可同时催化高氯酸铵(AP)和1,3,5‐三硝基‐1,3,5‐三嗪烷(RDX)的燃烧分解反应,其分解温度分别提前了25和11℃。

Asymmetric Synthesis of Anti-tuberculosis-specific Drug TBAJ-876 through Synergistic Li/Li Catalysis

TBAJ-876, developed by TB Alliance, a novel anti-tuberculosis-specific drug, has entered Phase II clinical trials. Herein, the first asymmetric synthesis of TBAJ-876 has been realized using synergistic Li/Li catalysis with excellent yield of 95% and 88 : 12 er (99.6 : 0.4 er, 10 : 1 dr after simple recrystallization). Furthermore, DFT calculations and 7Li-NMR analysis illustrated the mechanism of the synergistic reaction: a chiral Li-complex activates the nucleophile to control the stereoselectivity, while the other achiral Li-complex activates the electrophile to catalyze the carbonyl addition reaction. Additionally, this protocol has been successfully carried out at 5 gram-scale, showing its industrial potential.

配位环境对有机钛化合物催化聚酯缩聚反应的影响

为探究不同配位环境下有机钛化合物在聚酯缩聚反应过程中的催化性能,采用密度泛函理论(DFT)并结合对苯二甲酸双羟乙酯(BHET)合成聚酯的反应动力学实验,对四甲基酚合钛(Ti·[C_(7)H_(7)O]_(4),Cat1)、乙酰丙酮氧化钛(TiO·[C_(5)H_(7)O_(2)]_(2),Cat2)、异丙基三(二辛基焦磷酸酰氧基)钛酸酯(C_(51)H_(112)O_(22)P_(6)Ti,Cat3)3种有机钛化合物进行研究,分析配位基团的电子效应和空间位阻对有机钛催化活性的耦合影响。DFT计算结果表明,3种活性种的中心钛原子的Hirshfeld电荷数值分别为0.661、0.524、0.600,其亲电能力从大到小的顺序为Cat1、Cat3、Cat2。结构分析结果表明,中心钛原子的配位空间从大到小的顺序为Cat2、Cat1、Cat3。催化反应动力学实验表明,Cat1、Cat2、Cat3催化BHET合成聚酯的反应活化能分别为72.41、80.16、102.47 kJ mol,Cat1的催化活性最高,说明配位基团的电子效应和空间位阻共同影响钛催化剂的催化活性。研究结果可为钛系催化剂的设计及调控提供一定的理论基础和参考依据。

单原子催化剂中金属-载体强相互作用综述

单原子催化由于其独特的特性近年来在多相催化领域引发很大的关注。均匀分散的单原子可以作为催化活性中心,为实现催化反应的高选择性、高活性和研究其催化反应机理提供很大的可能。随着催化剂尺寸的逐步减小,催化剂的表面原子结构、电子结构和缺陷将发生明显变化,常常会产生金属-载体强相互作用。结合近年来单原子催化领域的研究工作,综述了单原子催化剂中金属-载体强相互作用的研究进展。介绍了单原子催化剂中金属-载体强相互作用的具体类型和表现形式,包括金属-金属相互作用、空隙或缺陷锚定、金属阳离子配位和有机配体络合。最后,基于对单原子催化剂中金属-载体强相互作用的理解和认识,对该研究领域的发展趋势和关键问题进行了展望。

H_(2)[SnCl_(6)]配位催化Beckmann重排反应研究

在反应条件相对温和且绿色环保高效的条件下,用成本低廉、方便易得的六氯合锡(IV)酸H_(2)[SnCl_(6)]作催化剂,实现了由二甲苯酮肟转变为N-苯甲酰替苯胺的Beckmann重排反应。在制备中间体酮肟的过程中,采用了流变相法,该法操作简便、反应时间短、且产率高,避免了强酸的使用;将酮肟转化为酰胺的Beckmann重排反应的过程中,选用了六氯合锡(IV)酸(H_(2)[SnCl_(6)])作为催化剂;同时,进一步探究催化剂使用的工艺条件,结果表明,当以乙腈为溶剂,反应温度78℃,催化剂用量为反应物物质的量的15%时,达到96.5%转化率和97.6%的选择性。在此条件下对另外所选的6种扩展底物进行了实验,结果显示当反应物的苯环上有推电子基团时转化率会提高,反之当有吸电子基团时则转化率则会降低;推测了可能的催化机理。