有序介孔有机金属 Pd(II) 的制备及其催化水介质中的 Suzuki 反应

 以有机金属 Pd 硅烷和乙基桥联硅烷为混合硅源, 在表面活性剂作用下进行共缩聚反应, 制备了有序介孔有机金属 Pd(II) 催化剂 Pd(II)-PMO(Et). 采用傅里叶变换红外光谱、核磁共振谱、X 射线衍射、透射电子显微镜和 N2 吸附脱附等手段对催化剂进行了表征. 结果表明, 与后嫁接法相比, 共聚法制得的催化剂活性位分散均匀, 孔道不易堵塞, 同时乙基修饰的孔壁增强了催化剂表面疏水性, 有利于反应物在孔道内的扩散和吸附. 在水介质 Suzuki 反应中, Pd(II)-PMO(Et) 的催化活性与均相催化剂 Pd(PPh3)2Cl2 的相当, 且可重复使用.     

周期有序介孔Rh(Ⅰ)有机金属催化剂用于水介质Heck反应的研究

以1,4-双(三乙氧基硅基)苯和2-(二苯基膦)乙基三乙氧基硅烷为混合硅源, 在表面活性剂作用下共缩聚得到二苯基膦功能化的有序介孔有机硅材料[PPh₂-PMO(Ph)], 通过配位作用将Rh(Ⅰ)有机金属催化剂固载到PPh₂-PMO上得到Rh(Ⅰ)-PPh₂-PMO(Ph)非均相催化剂, 并采用FTIR, NMR, XRD, TEM和氮气吸附等手段对催化剂进行了表征. 考察了该催化剂在水介质Heck反应中的催化性能, 实验结果表明, 所制备的Rh(Ⅰ)-PPh₂-PMO(Ph)具有与均相催化剂Rh(PPh₃)₃Cl相当的催化活性, 这主要归因于催化剂的高比表面积、有序介孔结构有利于提高Rh(Ⅰ)活性位的分散度, 减少了传质阻力; 同时PMO构建形成的微环境增强了表面疏水性, 有利于反应底物的吸附和扩散. 此外, 催化剂重复使用多次后活性仍没有明显降低.     

Au(Ⅰ)配合物催化剂室温高效催化炔烃水合反应

合成了一系列(1,1'-联苯)-2-二(1-金刚烷基)磷配体, 并制备出8种相应的Au(Ⅰ)配合物. 以甲醇为溶剂, 在6-十二炔水合反应中考察了8种Au(Ⅰ)配合物的催化性能, 结果表明, 以含有3'-(吡咯-1-羰基)官能团的Au(Ⅰ)配合物为催化剂时, 其用量仅需炔烃用量的0.1%~0.3%(摩尔分数), 室温下即可高效地催化炔烃进行水合反应.     

乙基桥联有序介孔有机硅负载Pd(Ⅱ)有机金属催化剂用于水介质Barbier反应

以PPh2C2H4-Si(OEt)3和(EtO)3Si-C2H4-Si(OEt)3为混合硅源,在表面活性剂作用下共缩聚制备有序介孔有机硅杂化材料,再络合Pd(Ⅱ)离子得到固载化Pd(Ⅱ)非均相催化剂.在水介质Barbier反应中,所制备的Pd(Ⅱ)-PPh2-PMO(Et)具有与均相Pd(PPh3)2Cl2催化剂相当的催化活性,主要归因于高比表面积、有序介孔结构,有利于提高Pd(Ⅱ)活性位分散度,减少传质阻力,同时乙基修饰孔壁增强表面疏水性,有利于有机分子在孔道内的扩散和活性位上的吸附,导致高催化活性,而且可重复使用,显示了良好的工业应用前景.     

金属及其化合物催化水相有机合成反应

近年来,水作为绿色溶剂应用于有机合成反应的报道不断涌现。本文综述了近五年来金属及其化合物催化的水相有机合成反应的研究进展,金属主要包括:钠、钾、铯、镁、铟、铋、钪、锰、铁、镍、锌、铜、银、金、钌、铑、钯、铱等。     

介孔有机金属Ru(Ⅱ)非均相催化剂的制备及其催化性能的研究

采用正硅酸乙酯和有机金属Ru(II)硅烷在模板剂P123作用下共聚,合成出有序介孔Ru(II)有机金属催化剂,通过FTIR、NMR、XRD、TEM、N2吸附脱附等对催化剂进行了系统表征;将该催化剂应用于水介质中烯丙醇型异构化反应,结果表明,其具有高活性和高选择性,催化效率接近均相催化剂,且能够多次重复使用,有望在绿色化工中推广应用.     

水滑石类催化剂催化制氢及生物炼制(英文)

近年来,水滑石由于其独特的性质受到越来越多的关注.作为非均相固体催化剂,水滑石及其衍生物具有优良的催化性能,因此得到了广泛研究和应用.本文简述了水滑石的几种合成方法,重点介绍了水滑石类催化剂在催化制氢和生物炼制方面的应用,并预测了水滑石类材料在新材料合成及环境友好催化体系中的应用前景.     

Au/MOF催化剂的制备、表征及其催化三组分偶联反应

采用后合成共价修饰法和一锅法分别制备了催化剂IRMOF-3-SI-Au(PS)和IRMOF-3-SI-Au(OP),运用X射线衍射、红外光谱、热重-差热分析、透射电镜以及程序升温还原对催化剂进行了表征,探索了这两种催化剂在醛、炔和胺三组分偶联反应中的催化性能,并推测了可能的反应机理.结果表明,两种催化剂对醛、炔和胺三组分偶联反应均具有较高的催化活性,产物炔丙基胺类选择性为100%,且可循环使用;结晶度较低的IRMOF-3-SI-Au(PS)的活性高于结晶度较高的IRMOF-3-SI-Au(OP);催化剂对芳香醛和脂肪醛以及环状胺均具有较高的催化活性,且对带有吸电子基团的芳香醛的活性高于带有供电子基团的.     

金属有机骨架高温自还原制备高性能等级孔碳负载Co基催化剂

以钴基金属有机框架为前驱体,利用一步高温碳化自还原法,通过精确调控碳化过程,实现等级孔道结构及钴纳米颗粒分散性的可控调节,制备出高催化活性及产物选择性的等级孔碳负载Co基催化剂.研究发现,600℃碳化后的催化剂为具有高比表面积的等级孔道结构和高分散的钴纳米颗粒,在选择性催化1,3-丁二烯加氢反应中,丁二烯完全转化温度低至60℃,对应丁烯的选择性高达61%,实现了低温高选择性催化加氢.     

Ni-Al复合氧化物/介孔杭锦2#土负载Au催化剂制备及其CO氧化催化性能

采用导向剂共沉淀-水热法合成不同复合量3Ni-Al类水滑石（LDH）/酸化杭锦2^#土载体前驱物.以液相还原-焙烧法制备不同Au负载量的Ni-Al复合氧化物/介孔杭锦2^#土负载Au催化剂.采用电感耦合等离子体发射光谱（ICP-AES）、原子吸收光谱（AAS）、N₂物理吸附-脱附、X射线衍射（XRD）、扫描电镜（SEM）、透射电镜（TEM）、紫外-可见漫反射光谱（UV-Vis DRS）、X射线光电子能谱（XPS）等手段对催化剂进行表征;并考察其催化CO氧化活性及稳定性.结果表明,3Ni-Al LDH在酸化杭锦2^#土上复合均匀;其负载Au后经500℃空气气氛焙烧,催化剂具有介孔结构,Au颗粒分散均匀、平均粒径小于10 nm;Ni-Al LDH复合量增加有利于纳米Au分散并抑制其粒径增大,且纳米Au与载体间存在较强相互作用;随Ni-Al LDH复合量和Au负载量增加,负载Au催化剂催化活性提高,当Ni-Al LDH复合量15%（Ni 3.47%）,Au负载量3%时,所得负载Au催化剂性能最佳：T₅₀为48℃,80℃时CO转化率大于90%,180℃连续反应10 h,CO转化率保持100%,空气放置110 d后,虽然其低温活性有所下降,但120℃时,仍可实现CO转化率大于90%.     

An active and recyclable bicontinuous cubic Ia3d mesostructural Rh(I) organometal catalyst for 1,4-conjugate addition reaction in aqueous medium

An active and reusable heterogeneous Rh(I) organometal catalyst (Rh(I)-PMO-3D) was synthesized by template-directed co-condensation of Rh[PPh₂(CH₂)₂Si(OCH₂CH₃)₃]₃Cl and (CH₃CH₂O)₃SiPhSi(OCH₂CH₃)₃. This catalyst displayed bicontinuous cubic Ia3d mesostructure channel, which ensured the high dispersion of Rh(I) active sites and the convenient diffusion of reactant molecules into the pore channels. Meanwhile, the Ph-functionalization could enhance the surface hydrophobicity, which promoted the adsorption of organic reactant molecules on the catalyst, especially in aqueous medium. During water-medium 1,4-conjugate addition reactions, Rh(I)-PMO-3D catalyst exhibits higher catalytic activity than the corresponding homogeneous Rh(I) catalyst and could be used repetitively for more than five times, showing a good potential in industrial applications.     

Monitoring of the Pre-Equilibrium Step in the Alkyne Hydration Reaction Catalyzed by Au(III) Complexes: A Computational Study Based on Experimental Evidences

The coordination ability of the [(ppy)Au(IPr)]²⁺ fragment [ppy = 2-phenylpyridine, IPr = 1,3-bis(2,6-di-isopropylphenyl)-imidazol-2-ylidene] towards different anionic and neutral X ligands (X = Cl⁻, BF₄⁻, OTf⁻, H₂O, 2-butyne, 3-hexyne) commonly involved in the crucial pre-equilibrium step of the alkyne hydration reaction is computationally investigated to shed light on unexpected experimental observations on its catalytic activity. Experiment reveals that BF₄⁻ and OTf⁻ have very similar coordination ability towards [(ppy)Au(IPr)]²⁺ and slightly less than water, whereas the alkyne complex could not be observed in solution at least at the NMR sensitivity. Due to the steric hindrance/dispersion interaction balance between X and IPr, the [(ppy)Au(IPr)]²⁺ fragment is computationally found to be much less selective than a model [(ppy)Au(NHC)]²⁺ (NHC = 1,3-dimethylimidazol-2-ylidene) fragment towards the different ligands, in particular OTf⁻ and BF₄⁻, in agreement with experiment. Effect of the ancillary ligand substitution demonstrates that the coordination ability of Au(III) is quantitatively strongly affected by the nature of the ligands (even more than the net charge of the complex) and that all the investigated gold fragments coordinate to alkynes more strongly than H₂O. Remarkably, a stabilization of the water-coordinating species with respect to the alkyne-coordinating one can only be achieved within a microsolvation model, which reconciles theory with experiment. All the results reported here suggest that both the Au(III) fragment coordination ability and its proper computational modelling in the experimental conditions are fundamental issues for the design of efficient catalysts.     

硫酸高铈催化炔烃的水合反应研究

炔烃经水合反应生成酮是有机合成中最重要和最基本的进行官能团转换的方法之一. 我们提供了一种价廉且具有高选择性的硫酸高铈催化炔烃水合方法. 实验结果表明: 在硫酸高铈(0.1 mmol)、浓硫酸(0.06 mL)、水(0.02 mL)和苯(5 mL)且反应温度为70 ℃的反应条件下, 炔烃(1 mmol)可以顺利发生水合反应生成酮.     

Reactions of Cationic Gold(I) with Allenoates: Synthesis of Stable Organogold(I) Complexes and Mechanistic Investigations on Gold‐Catalyzed Cyclizations

The reaction of allenoates with cationic gold(I)—generated in situ from a phosphine gold chloride and a silver salt—formed unusual, room temperature stable vinyl gold(I) lactones under very mild conditions. The scope and limitations for the synthesis of this novel organogold complex was investigated. DFT calculations on the highest occupied molecular orbitals (HOMOs) of allenoates and the natural bond orbital (NBO) charge densities provided an explanation for the limitations. A plausible mechanism for its formation was proposed based on in situ ¹H and ³¹P NMR spectroscopic analyses. Controlled experiments for the cleavage of the gold–carbon bond by electrophiles indicated that this vinyl gold(I) complex is the likely intermediate in the gold‐catalyzed reaction of carbon–carbon multiple bonds.     

Periodic mesoporous silica‐supported Ni(II) organometallic complex as an active and reusable nanocatalyst for water‐medium Sonogashira coupling reaction

Phenyl‐bridged periodic mesoporous organosilicas (PMOs) functionalized with diphenylphosphino (PPh₂‐) ligands were synthesized via a surfactant‐directed self‐assembly approach, and were used as a support to immobilize Ni(II) organometallic complex by coordination interaction. In comparison with Ni‐PPh₂‐SBA‐15 and Ni‐PPh₂‐PMOs(Et) catalysts, the as‐prepared Ni‐PPh₂‐PMOs(Ph) exhibited superior catalytic reactivity and selectivity in water‐medium Sonogashira reaction. A control experiment demonstrated that its high activity could be attributed to the high dispersion of Ni(II) active sites and ordered mesopore channels, which effectively diminished diffusion limitation. Meanwhile, the phenyl organic groups in the support wall enhanced surface hydrophobicity, which promoted the adsorption for organic reactant molecules. Moreover, it displayed almost the same catalytic efficiency with the corresponding homogeneous Ni(PPh₃)₂Cl₂ catalyst and could be used repetitively, which was considered as a more environmentally friendly catalytic process since it simultaneously avoided the use of noble metal active species and toxic organic solvents. Copyright © 2013 John Wiley & Sons, Ltd.     

Hypercoordinated compounds of gold(I)

Mono- and binuclear gold(I) derivatives ofortho-substituted diphenyl ether, C₆H₅OC₆H₄AuPPh₃ and O(C₆H₄)₂(AuPPh₃)₂, were prepared by the reaction of the 2,2'-dilithium derivative of diphenyl ether with ClAuPPh₃. X-Ray structural study has shown that these compounds contain secondary intramolecular bonds between the gold and oxygen atoms. The interaction of C₆H₅OC₆H₄AuPPh₃ with (AuPPh₃)BF₄ affords the [C₆H₅OC₆H₄(AuPPh₃)₂]BF₄ cationic complex. The latter reacts with PPh₃ to give the starting C₆H₅OC₆H₄AuPPh₃ complex.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 729–736, April, 1994.The authors wish to thank A. L. Blyumenfel'd for recording³¹P NMR spectra, D. V. Zagorevskii and K. V. Kazakov who obtained mass spectra, and Yu.L. Slovokhotov who carried out the EXSAFS study.The study described in the present paper was partly supported by the International Scientific Fund, grant N Ch. 002479.     

Mechanism of Gold(I)‐Catalyzed Conia‐ene Reaction of β‐Ketoesters with Alkynes: A DFT Study

Density functional calculations have been performed to comparatively investigate two possible pathways of Au(I)‐catalyzed Conia‐ene reaction of β‐ketoesters with alkynes. Our studies find that, under the assistance of trifluoromethanesulfonate (TfO), the β‐ketoester is the most likely to undergo Model II to isomerize into its enol form, in which TfO plays a proton transfer role through a 6‐membered ring transition state. The coordination of the Au(I) catalyst to the alkynes triple bond can enhance the eletrophilic capability and reaction activity of the alkynes moiety, which triggers the nucleophilic addition of the enol moiety on the alkynes moiety to give a vinyl‐Au intermediate. This cycloisomerizaion step is exothermal by 21.3 kJ/mol with an energy barrier of 56.0 kJ/mol. In the whole catalytic process, the protonation of vinyl‐Au is almost spontaneous, and the formation of enol is a rate‐limiting step. The generation of enol and the activation of Au(I) catalyst on the alkynes are the key reasons why the Conia‐ene reaction can occur in mild condition. These calculations support that Au(I)‐catalyzed Conia‐ene reactions of β‐ketoesters with alkynes go through the pathway 2 proposed by Toste.     

金催化的吲哚与末端炔烃的分子间烷基化反应

尝试了用金(Au)催化吲哚和炔烃的Friedel-Crafts烷基化反应, 具体探讨了金(I)配合物催化吲哚与末端炔烃的烷基化反应的条件, 并制备了一系列尚未见文献报道的双取代β-吲哚烷基化衍生物. 产物的结构经1H NMR, 13C NMR, MS和元素分析确证. 并对其反应机理可能性进行了推测.     

(Phosphine)gold(I) Complexes of Benzenedithioles. Crystal structures of 1,2-benzenedithiolato-bis[triphenyl-phosphinegold(I)] and bis(triethylphosphine)gold(I) bis(1,2-benzenedithiolato)gold(III)

The reaction of 1,2- and 1,3-benzenedithiol C₆H₄(SH)₂ with chloro(phosphine)gold(I) complexes R₃PAuCl (R = Et, Ph) in the presence of triethylamine in tetrahydrofuran gives stable gold(I) complexes 1,2-C₆H₄(SAuPR₃)₂ [R = Et ( 1 ) and Ph ( 2 )] or 1,3-C₆H₄(SAuPPh₃)₂ ( 3 ), respectively, in high yield. The compounds have been characterized by analytical and NMR spectroscopic data. From the reaction of 1,2-C₆H(SH)₂ with Et₃P? AuCl a by-product [(Et₃P)₂Au]⁺ [Au(1,2? C₆H₄S₂)₂]^? ( 4 ) has also been isolated in low yield. The crystal structures of compounds 2 and 4 have been determined by single crystal X-ray diffraction. The gold(I) atoms in complex 2 are two-coordinate with bond angles S? Au? P of 175.2(1) and 159.5(1)°, Au? S bond distances of 2.304(1) and 2.321(1) å, and a short Au…?Au contact of 3.145(1) Å. The gold(I) atom in the cation of complex 4 is also linearly two-coordinate with a P? Au? P angle of 170.1(1) Å and Au? P distances of 2.296(3) and 2.298(3) Å. The geometry of the anion in 4 shows a square-planar coordination of gold(III) by two chelating 1,2-benzenedithiolate ligands with Au? S distances between 2.299(3) and 2.312(3) Å (for two crystallographically independent, centrosymmetrical anions in the unit cell).     

Tetranuclear Dicationic Aurophilic Gold(I) Catalysts in Enyne Cycloisomerization: Cooperativity for a Dramatic Shift in Selectivity

In comparison to mononuclear gold Lewis acid catalysts, digold complexes and dual-gold catalysis have illustrated a distinct and powerful potential for the activation of carbon-carbon multiple bonds. Herein, this concept is pushed further by designing novel tetranuclear gold(I) dicationic complexes structurally supported by strongly stabilizing constraint diphosphinoferrocenyl ligands and attractive closed-shell Au⋅⋅⋅Au aurophilic interactions. The use of a molecularly-defined tetranuclear dicationic aurophilic gold(I) precatalyst for the selectivity-challenging cycloisomerization of low-substituted 1,6-enynes favors the formation with high selectivity of strained azabicyclo[4.1.0]hept-4-enes – even in the complete absence of activating/orienting substituents on alkyne and olefin reactive functions. This selectivity is not achieved by the reported phosphine- and carbene-stabilized mono- and dinuclear cationic gold(I) complexes, including the ones formed from the same ligands. More importantly this selectivity differs also from nanoparticles and heterogeneous gold catalysts reported to date. DFT studies correlated to experimental mechanistic investigations support an unprecedented “cluster-like” reactivity from polynuclear cooperation at the origin of this peculiar selectivity where the aurophilic interactions preexist, and pre-organize, gold cluster reactive intermediates.