新型含N-杂环卡宾二硫化碳配体的锰铼金属双核化合物的合成、表征及电化学性质

合成了一系列含N-杂环卡宾二硫化碳加合物配体的锰铼金属有机化合物, 其中包括3种单核化合物和3种双核化合物, 对它们的结构进行了表征, 并研究其反应性和电化学性质. 与三烷基膦二硫化碳配体相比, 含N-杂环卡宾二硫化碳加合物配体的锰铼金属有机化合物展现出不同的反应特性. 研究结果表明, [MnRe(CO)₆(μ-H){μ-CH₃SC(S)IMes₂}]配合物具有催化质子还原成氢气的能力.     

金属苯炔的合成与化学性质

金属苯炔是一类新颖的杂环芳香化合物.它们可看成是苯炔分子中的一个碳原子被等瓣的过渡金属基团取代而衍生出来的六元杂环化合物.近年来,金属苯炔的化学引起了人们的兴趣和关注.一系列含锇和铼的金属苯炔已被成功地合成和鉴定.这些金属苯炔不仅具有有机化合物的芳香性,还具有金属有机化合物的属性.它们既可以发生芳香体系的经典反应(如亲电取代反应),也可以发生金属有机化合物的反应(如卡宾化合物的形成).     

异核多金属N-杂环卡宾化合物的合成及应用

以N-杂环卡宾为配体的异核多金属化合物的合成、物理化学性质以及应用取得了很大的发展,尤其在多步串联催化反应方面显示出了优越的催化活性。本文根据构建异核多金属的配体种类,对异核多金属N-杂环卡宾化合物的合成及其应用进行了分类总结,并对异核多金属N-杂环卡宾化合物未来的研究前景进行了展望。     

N-杂环卡宾及其金属络合物的合成*

由于其强给电子能力、结构易修饰性和拓扑学特性,N-杂环卡宾成为继有机膦配体之后又一类重要的配体。其金属络合物在均相及不对称催化领域的催化性能是近期研究的热点,已有许多成功的结果。本文综述了近年来N-杂环卡宾及其金属络合物以及N-杂环卡宾的重要前体咪唑盐的合成方法。金属-N-杂环卡宾络合物的合成方法包括：(a)游离卡宾与金属化合物直接络合;(b)咪唑盐与金属化合物在强碱作用下络合;(c)利用Ag-NHC通过卡宾配体转移方法制备新的金属络合物。关于N-杂环卡宾前体的合成途径主要有：(a)乙二醛、伯胺和多聚甲醛的缩合反应;(b)卤代烷与咪唑及其取代咪唑的烷基化反应;(c)原甲酸酯与1,2-二胺的成环反应;(d)肼或酰胺与酸酐的环化反应;(e)用Na/K对环硫脲化合物的还原反应。     

N-杂环卡宾金属配合物在酮硅氢加成反应中的新进展

N-杂环卡宾是一类新型催化剂和配体, 在有机化学中得到了极大的重视. N-杂环卡宾金属配合物的研究在近几年来得到迅速的发展,总结了酮硅氢加成反应中N-杂环卡宾金属配合物催化剂的应用新进展.     

过渡金属N-杂环卡宾配合物合成*

由于N-杂环卡宾配体（NHCs）的独特性能,N-杂环卡宾过渡金属配合物在均相催化等方面取得了重要应用,但是其合成方法却发展缓慢。本文综述了N-杂环卡宾过渡金属配合物合成方法的最新研究进展,介绍了富电子烯烃裂解反应、游离NHC直接配位反应、配体底物的脱质子原位反应、卡宾加合物热解反应、金属交换转移反应和C2-X（X为甲基、卤原子或氢原子）键氧化加成反应等合成N-杂环卡宾过渡金属配合物的主要方法,此外本课题组还首次发现了金属粉末法,该法可用于规模化合成铁、钴、镍、铜等第一过渡系金属NHC配合物。     

基于氮杂环卡宾的多齿C,N-配体过渡金属化合物的合成与应用

综述了基于氮杂环卡宾的多齿C,N-配体过渡金属化合物的合成与应用研究的最新进展,结合本课题组的工作介绍了含有吡啶、嘧啶、吡唑、萘啶、哒嗪、三唑和邻菲罗啉等氮杂环基团的氮杂环卡宾过渡金属化合物在有机合成中的应用.     

镍N-杂环卡宾配合物在均相催化偶联反应中的应用

 近十几年来, N-杂环卡宾的配位化学和金属有机化学发展迅速, 已成为均相催化反应中研究最为广泛的配体之一. 在许多过渡金属催化的有机合成反应中特别是偶联反应中, N-杂环卡宾与传统有机膦配体相比具有较高的反应性. 镍价格低廉, 在很多反应中有望替代贵金属钯催化剂. 本文总结了镍 N-杂环卡宾化合物在催化交叉偶联反应和还原偶联反应中的最新应用进展.     

多咪唑盐合成的N-杂环卡宾金属配合物研究进展

N-杂环卡宾金属配合物具有良好的化学稳定性和催化活性,一直是有机化学研究领域中的热点.咪唑盐作为N-杂环卡宾的前体,其制备容易,结构多样的特点为构建拓扑结构的N-杂环卡宾金属配合物提供了基础.主要针对近年来由环状多咪唑盐、非环状多咪唑盐为配体与金属进行组装,或以咪唑盐与P/N配体与金属共同组装,或经过异腈分布合成法形成的具有特殊柱状、笼状、环状、"分子方"和"分子矩形"等结构的多N-杂环卡宾金属配合物的合成,结构及物理化学性质进行归纳总结,并对其研究前景进行了展望.     

铜N-杂环卡宾化合物的合成及其在有机合成中的应用

N-杂环卡宾铜化合物具有简便易得,价廉低毒,性质稳定,结构类型多样并易于修饰等诸多优点,在很多领域具有重要的应用价值,因此铜的N-杂环卡宾化学在过去十几年中得到了快速发展。本文结合我们的工作,总结铜N-杂环卡宾化合物的合成方法、结构特点、转移卡宾配体用于合成其它金属卡宾化合物以及催化应用。     

Paramagnetic metal chelates of an o-quinone derivative of fullerene with Mn and Re carbonyls

Reactions of the ^·M(CO)₅ radicals (M = Mn and Re) with an o-quinone derivative of fullerene C₆₀ yield stable paramagnetic complexes (ESR data). Two carbonyl ligands in the resulting spin adducts were replaced by PPh₃.     

Infrared studies of surface carbonate binding to diimine-tricarbonyl Re(I) and Mn(I) complexes in mesoporous silica

Abstract

Diimine-tricarbonyl Re(I) and Mn(I) complexes have demonstrated interesting activity in photocatalytic and electrochemical CO₂ reduction. In this study, we take a surface chemistry approach to investigate interactions of CO₂ with Re(I) and Mn(I) complexes in the presence of triethylamine. The molecular complexes were adsorbed on the surface of a mesoporous silica. Under dark conditions, formation of metal-carbonate adducts was observed by infrared spectroscopy in the presence of CO₂, triethylamine, and surface silanol groups. The Langmuir adsorption model was utilized to extract quantitative information regarding surface carbonate binding to the two molecular complexes. The results indicate that binding of carbonate was much stronger on the Re(I) center than on Mn(I), consistent with prior observations regarding the relative activities of these complexes in CO₂-reduction catalysis.     

Replacement of Volatile Acetic Acid by Solid SiO2@COOH Silica (Nano)Beads for (Ep)Oxidation Using Mn and Fe Complexes Containing BPMEN Ligand

Mn and Fe BPMEN complexes showed excellent reactivity in catalytic oxidation with an excess of co-reagent (CH₃COOH). In the straight line of a cleaner catalytic system, volatile acetic acid was replaced by SiO₂ (nano)particles with two different sizes to which pending carboxylic functions were added (SiO₂@COOH). The SiO₂@COOH beads were obtained by the functionalization of SiO₂ with pending nitrile functions (SiO₂@CN) followed by CN hydrolysis. All complexes and silica beads were characterized by NMR, infrared, DLS, TEM, X-ray diffraction. The replacement of CH₃COOH by SiO₂@COOH (100 times less on molar ratio) has been evaluated for (ep)oxidation on several substrates (cyclooctene, cyclohexene, cyclohexanol) and discussed in terms of activity and green metrics.     

Synthesis and Characterization of a New (E,E)-Dioxime and its Homonuclear Complexes

N′-(4′-Benzo[15-crown-5]naphthylaminoglyoxime (H₂L) and its sodium chloride complex (H₂L·NaCl) have been prepared from 2-naphthylchloroglyoxime, 4′-aminobenzo[15-crown-5] and sodium bicarbonate or sodium bicarbonate and sodium chloride. Nickel(II), cobalt(II) and copper(II) complexes of H₂L and H₂L·NaCl have a metal–ligand ratio of 1:2 and the ligand coordinates through the two N atoms, as do most of the vic-dioximes. The BF₂⁺-capped Ni(II), Co(III) and mononuclear complexes of thevic-dioxime were prepared. The macrocyclic ligands and their transition metal complexes have been characterized on the basis of IR, ¹H NMR spectroscopy and elemental analyses data.     

Synthesis,structure and catalase activity of the [TPA2Mn2(μ-Cl)2] complex

The dinuclear Mn complex (Et₃NH)₂[TPA₂Mn₂(μ-Cl)₂](ClO₄)₄ (I) was synthesized and characterized. Complex I was obtained from the reaction between MnCl₂ and [H₃TPA](ClO₄)₃ in MeOH. Structural analysis of I showed the two Mn(II) atoms are bridged by two chloride ligands, forming a bis(μ-chloro)dimanganese core. The [Mn₂(μ-Cl)₂]²⁺ core, with a Mn–Mn distance of 3.521(2) Å, is similar to the active site found in chloride-inhibited Mn catalase. EPR and temperature-dependent magnetic susceptibility measurements of complex I showed an antiferromagnetic interaction between the two S = 5/2 Mn centers with an exchange parameter J = −8.8 cm⁻¹. Catalytic activity of H₂O₂ dismutation was measured for complex I and compared with other related complexes. Kinetic parameters of H₂O₂ dismutation were obtained and a possible catalytic mechanism of complex I, related to chloride-inhibited Mn catalase, was suggested.     

New direction in organopalladium chemistry: structure and reactivity of unsaturated hydrocarbon ligands bound to multipalladium units

Examination of the manner of interaction between Pd(0) and allylpalladium(II) complexes, both being involved as key intermediates in Pd-catalyzed allylic coupling, led us to discover a new role for such combinations in affecting the stereochemistry of the transformations. A similar investigation of the system involving Pd(0) and allenyl/propargyl complexes of Pd(II) led to the discovery of dinuclear Pd(I)bond;Pd(I) complexes containing bridging allenyl/propargyl ligands, which exhibited novel structural and reactivity aspects of great synthetic significance. A systematic comparison was made between the structure, stability, and reactivity of allyl and allenyl/propargyl ligands in dinuclear complexes and those in mononuclear counterparts. On the basis of MO calculations, coordination behavior specific to the ligands of the dinuclear complex is attributed to the occurrence of the back-donating interaction from filled Pdbond;Pd bonding orbitals to vacant ligand pi* orbitals. Similar bonding features are the origin of the ready synthesis of novel one-dimensional sandwich complexes composed of conjugated polyene ligands and linear polypalladium chains. A substitutionally labile dipalladium complex reacts with an equimolar amount of trienes or alkynes to give formal [4pi + 2sigma] or [2pi + 2sigma] adducts, respectively, which undergo further unique transformations with additional unsaturated substrates.     

Perfluormethyl‐Element‐Liganden. XLIII [1] Neue Synthesewege zu Zweikernkomplexen des Typs MM′(CO)8ER2X (M/M′ = Mn/Mn,Mn/Re,Re/Re; E = P,As; R = CF3, Me; X = Hal)

Perfluoromethyl Element Ligands. XLIII [1] Novel Synthetic Routes to Binuclear Complexes of the Type MM′(CO)₈ER₂X (M/M′ = Mn/Mn, Mn/Re, Re/Re; E = P, As; R = CF₃, Me; X = Hal, ) Mn(CO)₅I reacts with compounds of the type (CF₃)₂EAsMe₂ (E = P, As) as with the symmetric E₂(CF₃)₄ ligands in the first step with cleavage of the E‐As bond to yield the pro ducts (CO)₅MnE(CF₃)₂ and Me₂AsI. Reaction of the mononuclear complexes with excess of Mn(CO)₅I leads in good yields to the known dinuclear compounds (CO)₄Mn[E(CF₃)₂, I]Mn(CO)₄ and CO. Me₂AsI, the second product of the EAs cleavage, attacks the starting compound Mn(CO)₅I giving cis‐Mn(CO)₄I(AsMe₂I) and CO. This result encouraged us to thoroughly investigate the preparation of cis‐M(CO)₄X(EMe₂Y) complexes with most of the possible combinations of M = Mn, Re; E = P, As and X, Y = Cl, Br, I. An alternative route to these compounds was opened by the cleavage of the dinuclear manganese or rhenium halides M₂(CO)₈X₂ with the halophosphanes or ‐arsanes Me₂EY. This route was found to be especially advantageous for the preparation of the rheniumcarbonyl precursors, since milder conditions than for the CO‐substitution in Re(CO)₅X compounds are sufficient for the halogen‐bridged dinuclear complexes. Cis‐M(CO)₄X(EMe₂Y) complexes were used as precursors for the synthesis of novel homo‐ and heterodinuclear complexes of the type (CO)₄M(EMe₂, X)M′(CO)₄ by reacting the EY function with transition metal carbonylates Kat[M′(CO)₅] (Kat = Na, Bu₄N, Ph₄As). Thus the preparation of a wide range of complexes was possible, which before had been successfully prepared by the direct reaction of Mn₂(CO)₁₀ with Me₂EX only in few cases, e. g. with Me₂AsI. Spectroscopic investigations, using the CO valence frequencies and the ¹H‐NMR data of the ligands EMe₂Y or of the Me₂E bridges, were applied to study the influence of the variables M, M′, E, X, Y and Kat on the reactivity of the mononuclear complexes and the bonding situation in both the mono‐ and the dinuclear systems. The new compounds were characterized by spectroscopic (IR, NMR, MS) and analytic methods (C, H).     

Oxidation of Organometallic Compounds

Stable organometallic compounds, notably of the later transition metals (groups VI–VIII), usually are characterized by closed shell electron configurations (typically 18-electron valence shells) which are destabilized by electron addition or removal. One-electron oxidation of such compounds results in the formation of unstable radical ions, whose characteristic reactivity patterns include susceptibility to nucleophilic attack, disproportionation, and metal-carbon bond dissociation. Two-electron oxidation may result in dissociation or oxidation of the organic ligand. In this review studies on the chemical and electrochemical oxidations of metal carbonyls, metal-olefin complexes, and alkyl transition-metal compounds are described. The studies encompass the following themes: (1) The kinetics and thermodynamics of the initial redox steps; (2) The characterization and reactivity patterns of the resulting oxidation products; (3) The synthetic and catalytic applications of organometallic redox processes.     

Photochromic and redox properties of bisterpyridine ruthenium complexes based on dimethyldihydropyrene units as bridging ligands

We report herein the synthesis and characterization of four new bisterpyridine dinuclear ruthenium complexes containing the dimethyldihydropyrene (DHP) photochrome as bridging ligand. A synthetic strategy has been developed based on a Suzuki coupling reaction to synthesize these novel terpyridine-DHPs. The reactivity of these different ligands and dinuclear ruthenium complexes with light was examined by (1)H NMR and monitoring the changes in their absorption spectra upon irradiation at controlled wavelengths. The free ligands and their corresponding ruthenium complexes all displayed photochromic properties with highly efficient conversion between the closed stable isomers (DHP) and their open forms (CPD). The properties of the compounds in their closed and open forms were investigated by cyclic voltammetry, spectroscopy, and luminescence measurements.