三钌乙烯酮原子簇化合物[PPN]_2[Ru_3(CO)_9(CCO)]在SiO_2上的负载及其催化性能的研究

[PPN]_2[Ru_3(CO)_9(CCO)]负载于SiO_2表面后,其红外谱图显示2068,2036,2000,1974和1925cm~(-1)谱带,表明[Ru_3(CO)_9(CCO)]~(2-)同Si—OH基因反应,形成了[HRu_3(CO)_9-(CCO)]~-/SiO~2。在600～720cm~(-1)区间,出现694cm~(-1)谱带,归属于[HRu_3(CO)_9(CCO)~-/SiO_2的VRu_H_Ru(out-of-plane)。通过(13)~CO和CO同位素交换反应,提出1974和1940cm~(-1)谱带分别归属于CCO和C~(13)CO基团的VCO和V13CO。在乙烯甲酰化和CO加氢反应中,由[PPN]_2-[Ru_3(CO)_9(CCO)]制备的催化剂对形成烃和含氧化合物的反应活性远远大于由[PPN]-[HRu_3(CO)_(11)]制备的催化剂,表明CCO是形成产物的活性中间体。     

SiO_2担载的三钌乙烯酮原子簇化合物[PPN]_2[Ru_3(CO)_9(CCO)]的原位FTIR-TPD-MASS研究

用原位FTIR-TPD-MASS法研究了SiO_2担载的[PPN]_2[Ru_3(CO)_9(CCO)]。结果表明,随温度的升高,[HRu_3(CO)_9(CCO)]~-/SiO_2的CO不断脱附,在433K时,形成Ru_3CCO。升温到573K时,Ru_3CCO继续脱CO而成三钌碳化物Ru_3C:,后者可以和CO反应重新形成Ru_3CCO。在H_2条件下,Ru_3C:可加氢生成CH_x(X=1～3),甚至CH_4。Ru_3C:在473K下氢还原1小时,并在室温下引入CO后,除～1974cm~(-1)峰之外,还出现了一个1708cm(-1)新谱带,它归属于在Ru_3原子簇上的面式吸附。     

氧化镁担载的[PPN]_2[Ru_3(CO)_9CCO]作为C_2含氧化合物模型的表面金属有机化学的研究

用原位红外光谱法研究了负载于MgO表面上的〔PPN〕_2〔Ru_3(CO)_9CCO〕簇合物。发现表面物类同MgO的抽空脱水温度有很大关系。在573K以下脱水的氧化镁上〔PPN〕_2〔Ru_3-(CO)_9CCO〕吸附后,其v_(?)=o的红外谱基本保持乙烯酮钌簇合物的原来特征,〔Ru_3(CO)_9-CCO〕~(2-)离子和表面的电荷相互作用只引起线式和桥式CO谱带的轻微位移。抽空脱水温度超过613K时,除了〔Ru_3(CO)_9CCO〕~(2-)的特征光谱外,还出现2068,2030和1999cm~(-1)新谱带,归因于Mg-OH同〔Ru_3(CO)_9CCO〕~(2-)反应部分地形成〔HRu_3(CO)_9CCO〕~-.TPD-IR研究揭示了〔Ru_3(CO)_9CCO〕~(2-)/MgO的热稳定性远大于〔PPN〕_2〔Ru_3(CO)_9CCO〕固体。在CO气氛下,〔Ru_3(CO)_9CCO〕~(2-)同CH_3I很易反应,v_(?)=o谱带的变化说明反应后有乙酰基生成,v_(?)=o谱带出现在1635cm~(-1)。这种含乙酰基的三钌化合物〔Ru_3(CO)_9CC(O)CH_3〕~-对CO+H_2合成C_2含氧物的机理研究,可能有模型化合物的意义。     

表面金属有机化学—表面担载的三钌乙烯酮化合物及其催化性能

本文利用原位红外光谱方法研究了三钌乙烯酮化合物在无机载体SiO_2、SiO_2-Al_2O_3和MgO表面上的负载,发现[Ru_3(CO)_9(CCO)]~(2-)分别同SiO_2和SiO_2-Al_2O_3表面上的羟基反应,选择性地定量形成[HRu_3(CO)_9(CCO)]~-/SiO_2和H_2Ru_3(CO)_9(CCO)/SiO_2-Ai_2O_3,而在MgO表面上,[Ru_3(CO)_9(CCO)]~(2-)保持其结构。对~(13)CO同位素交换,H_2Ru_3(CO)_9(CCO)/SiO_2-Al_2O_3显示了很高活性,而[Ru_3(CO)_9(CCO)]~(2-)/MgO则完全不反应。在甲基化反应中,[Ru_3(CO)_9(CCO)]~(2-)/MgO对CH_3I显示了很高活性,但对CH_3Li却不反应,对H_2Ru_3(CO)_9(CCO)/SiO_2-Al_2O_3,它与CH_3I不显示活性,但却和CH_3Li较易反应;[HRu_3(CO)_9(CCO)]~-/SiO_2的甲基化的活性顺序处于上述MgO和SiO_2-Al_2O_3担体上的簇合物之间。通过乙烯甲酰化反应可以看到,在(Ru_3(CO)_9(CCO)]~(2-)/MgO上,对于含氧化合物的形成显示了高活性,而对于H_2Ru_3(CO)_9(CCO)/SiO_2-Al_2O_3则有利于形成烃类化合物。     

SiO_2-Al_2O_3担载的三钌乙烯酮原子簇化合物[PPN]_2[Ru_3(CO)_9(CCO)]的红外研究

[PPN]_2[Ru_3(CO)_9(CCO)]负载于SiO_2-Al_2O_3表面后其红外光谱显示了2124,2088,2060,2040和2010cm(-1)几个谱带,认为这是由于[Ru_3(CO)_9(CCO)]~(2-)同SiO_2-Al_2O_3的Si(OH)Al基团(3620 cm~(-1))反应生成了H_2Ru_3(CO)_9(CCO)/SiO_2-Al_2O_3     

CATALYTIC PERFORMANCE OF ETHYLENE HYDROFORMYLATION OVER[H_XRu_3(CO)_9(CCO)]~(2-X)/SiO_2-Al_2O_3,SiO_2 AND MgO(X=0-2)CATALYSTS

The various surface species[H_XRu_3(CO)_9(CCO)]~(2-X)(X=0-2)prepared fromimpregnation of[PPN]_2[Ru_3(CO)_9(CCO)]on SiO_2-Al_2O_3,SiO_2 and MgO show quite differentactivities and selectivities for oxygenates and ethane in ethylene hydroformylation.     

三核钌簇合物[PyCH=C(Ph)O]_2Ru_3(CO)_8的合成、结构及反应性（英文）

配体PyCH_2COPh与Ru_3(CO)_(12)在甲苯中加热回流,得到了标题簇合物[PyCH=C(Ph)O]2Ru3(CO)8(1)。通过红外光谱、核磁共振氢谱和碳谱对1的结构进行了表征,用X射线单晶衍射法测定了1的结构。结果表明:3个钌原子呈等腰三角形分布,其中Ru(2)-Ru(1)和Ru(2)-Ru(1)i的键长均为0.280 nm,Ru(1)-Ru(1)i的键长为0.307 nm。同时研究了簇合物1与环戊二烯及茚的反应,分别得到双核钌羰基配合物[(η~5-C_5H_5)Ru(CO)]_2(μ-CO)_2(2)和[(η~5-C_9H_7)Ru(CO)]2(μ-CO)_2(3)。     

In situ infrared investigation of alkylation reaction of dianionic triruthenium ketenylidene cluster on magnesium oxide with methyl iodide

The reaction between [Ru_3(CO)_9(CCO)]~(2-) supported on magnesium oxide and alky-lating agent CH_3I was investigated in an attempt to understand its reactivity and mechanism byusing FT-IR technique. The IR spectra show that [Ru_3(CO)_9(CCO)]~(2-)/MgO reacts with CH_3Ito produce [Ru_3(CO)_9CC(O)CH_3]-/MgO, which exhibits bands at 2960, 2022, 1988, 1638, 1460and 1350 cm~(-1). The absorption at 2960, 1460 and 1350 cm~(-1) are attributed to -CH_3 group, whilebands at 2022, 1988 and 1952 cm~(-1) are assigned to the terminal CO groups attached to ruthenium.The band at 1638 cm~(-1) was assigned to acyl carbonyl. Isotopes labeled compounds CD3I, ~(13)COand [Ru_3(CO)_9(*C*CO)]~(2-) were used in investigation. The results demonstrate that β-carbon ofCCO ligand is attacked by CH_3~+ species and produces [Ru_3(CO)_9CC(O)CH_3]-/MgO.     

催化乙烯醛化的钌羰基原子簇新体系

发现了乙烯醛化的一个有效的新催化体系,它由钌原子簇H_4Ru_4(CO)_(12)或Ru_3(CO)_(12),卤化物和碱金属阳离子促进剂组成。在碱性的四氢呋喃-水溶液中,C_2H_4,H_2和CO的分压为1:2:2(总压小于75kg/cm~2)及125～175℃的条件下,其催化活性正比于反应温度、C_2H_4、H_2和CO的分压。添加卤化物和碱金属阳离子极大地提高了催化活性并得到如下顺序:NaI/NaOH 相似文献   

ACTIVITY AND SELECTIVITY OF RUTHENIUM CARBONYL,KETENYLIDENE AND CARBIDE CLUSTER-DERIVED CATALYSTS FOR ETHYLENE HYDROFORMYLATION AND CO HYDROGENATION

The ruthenium catalyst prepared from triruthenium ketenylidenecluster exhibited high catalytic activity in hydroformylation of ethylene and COhydrogenation,compared with the catalyst from[HRu_3(CO)_(11)]~-.The highactivity possibly resulted from the ketenyl group(CCO)that could be partlyconverted to carbide species.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.