酸性离子液调控下咪唑硫酸四铁簇合物和铁-DMSO配合物的合成

FeCl₂与酸性离子液在乙醇中反应制备得到咪唑硫酸铁簇合物[HMIM]₂[Fe₂O（SO₄）₃（DMSO）₂]·0.5DMSO（1）和[HPIM]₄[Fe₄O₂（SO₄）₆（DMSO）₄]·2MeCN（2）,该类簇合物为四核铁簇Fe₄（O）₂（SO₄）₆（DMSO）₄结构,4个Fe原子通过中心μ₃-O桥、硫酸根上的μ₂-O和μ₃-O桥连接,形成共平面结构,中间的四核铁簇为-4价,4个质子化的咪唑正离子起电荷平衡作用。该簇合物的晶体结构属于三斜晶系中的P1空间群。变温磁化率测试表明该簇合物具有强的反铁磁性。但在类似的反应条件下,FeCl₃在酸性离子液反应没有得到类似的簇合物,而是得到DMSO配合物[FeCl₂（DMSO）₄][EtSO₄]·DMSO（3）。     

一类六核三价铁簇化合物的合成及结构表征

选择3种不同尺寸含氮配体（哌嗪、咪唑和三氮唑）与三羟甲基丙烷（H₃tmp）和FeCl₃采用溶剂热反应合成3例六核Fe（Ⅲ）合物：（C₅H₁₄N₂）[Fe₆（μ₆-O） Cl₆（tmp）₄]·2H₂O·CH₃OH（1）、（C₃H₅N₂）₂[Fe₆（μ₆-O） Cl₆（tmp）₄]（2）和（C₄H₈N₃）₃（C₂H₄N₃）[Fe₁₂（μ₆-O）₂Cl₁₂（tmp）₈]·3CH₃OH（3）,并对它们的结构进行表征。发现三元醇配体有利于合成高核金属簇。3个化合物具有相同的阴离子簇[Fe₆（μ₆-O） Cl₆（tmp）₄]^2-。通过晶体学参数,元素分析,红外等手段证实,在化合物1和3的体系中,氮杂环配体经历了N-和C-烷基化反应。     

一类六核三价铁簇化合物的合成及结构表征

选择3种不同尺寸含氮配体（哌嗪、咪唑和三氮唑）与三羟甲基丙烷（H₃tmp）和FeCl₃采用溶剂热反应合成3例六核Fe（Ⅲ）合物：（C₅H₁₄N₂）[Fe₆（μ₆-O）Cl₆（tmp）₄]·2H₂O·CH₃OH （1）、（C₃H₅N₂）₂[Fe₆（μ₆-O）Cl₆（tmp）₄] （2）和（C₄H₈N₃）₃（C₂H₄N₃）[Fe12（μ₆-O）₂Cl₁₂（tmp）₈]·3CH₃OH （3）,并对它们的结构进行表征。发现三元醇配体有利于合成高核金属簇。3个化合物具有相同的阴离子簇[Fe₆（μ₆-O）Cl₆（tmp）₄]^2-。通过晶体学参数,元素分析,红外等手段证实,在化合物1和3的体系中,氮杂环配体经历了N-和C-烷基化反应。     

一例可分离的双核铁氢自由基阳离子

成功分离得到了一例双核铁氢自由基阳离子盐cis-[Fe₂Cp₂（μ-H）（μ-PPh₂）（CO）₂]^·+[Al（OC（CF₃）₃）₄]^-（cis-1^·+[Al（OC（CF₃）₃）₄]^-）晶体，并使用单晶X射线衍射、电子顺磁共振、红外光谱、紫外-可见光谱以及密度泛函理论对它进行了表征和理论计算。电子顺磁共振和密度泛函理论计算分析表明，自由基的自旋密度主要均等分布于2个铁原子上。     

基于四甲基取代六元瓜环的四核稀土镝簇合物的慢磁弛豫

报道了2个基于四甲基取代六元瓜环的三明治型四核稀土簇合物,[Ln₄(μ₃-OH)₄(μ₂-OH)₂(H₂O)₄(NO₃)₂(TMeQ[6])₂]·(NO₃)₄·26H₂O(Ln=Dy,1;Ln=Tb, 2)。晶体结构分析显示2个簇合物包含2个四甲基取代瓜环夹心的四核稀土立方烷结构,[Ln₄(μ₃-OH)₄]⁸⁺。磁性研究显示化合物1显示了慢磁弛豫行为。由于六元瓜环配体可以有效的传递能量给稀土铽离子,化合物2具有较好的发光性能。     

基于双吡啶脲类Cd(Ⅱ)、Zn(Ⅱ)、Hg(Ⅱ)配合物的合成及晶体结构

间苯二胺和3-吡啶异氰酸酯在甲苯中加热回流得到双吡啶脲类配体L,然后将配体分别与CdSO₄·8H₂O,ZnI₂,HgI₂,HgCl₂进行配位反应,得到4个配合物{[Cd（L）（SO₄）（H₂O）₃]·H₂O}_n（1）,{[Zn（L）I₂]·2C₂H₅OH}_n（2）,{[Hg（L）I₂]·C₂H₅OH}_n（3）,[Hg（L）Cl₂]·H₂O（4）,并用元素分析、FT-IR、X射线单晶衍射、粉末衍射对其进行了表征。配合物1形成一维螺旋链结构,配合物2和3形成一维“之”字链结构,配合物4形成32元环状结构。     

基于四甲基取代胍环的四核稀土镝簇合物的慢磁弛豫

报道了2个基于四甲基取代胍环的三明治型四核稀土簇合物, [Ln₄(μ₃-OH)₄(μ₂-OH)₂(H₂O)₄(NO₃)₂(TMeQ[6])₂]·(NO₃)₄·26H₂O(Ln=Dy, 1; Ln=Tb, 2)。晶体结构分析显示2个簇合物包含2个四甲基取代胍环夹心的四核稀土立方烷结构, [Ln₄(μ₃-OH)₄]⁸⁺。磁性研究显示化合物1显示了慢磁弛豫行为。由于胍环配体可以有效的传递能量给稀土铽离子, 化合物2具有较好的发光性能。     

基于二吡唑配体的镉配合物:温度诱导自组装、荧光和光催化应用

通过改变溶剂热反应温度,合成了2个结构不同的镉配合物[Cd₂（H₂ppty）₂（SO₄）₂（H₂O）₂]·3H₂O（1）和[Cd₂（ppty）（SO₄）（H₂O）₂]_n（2）（H₂ppty=3,5-bis-（1H-pyrazol-3-yl）-[1,2,4]triazol-4-ylamine）。进一步的研究表明,1和2的结构分别包含有双核和四核镉簇单元,呈现出零维和二维的结构。并且在室温下对2个配合物的荧光性质也进行了测试。固体紫外漫反射表明1和2的光学带隙分别为1.87和2.32 eV,因此它们对亚甲基蓝的光降解反应表现出了良好的催化活性。     

基于二吡唑配体的镉配合物:温度诱导自组装、荧光和光催化应用

通过改变溶剂热反应温度,合成了2个结构不同的镉配合物[Cd₂（H₂ppty）₂（SO₄）₂（H₂O）₂]·3H₂O（1）和[Cd₂（ppty）（SO₄）（H₂O）₂]_n（2）（H₂ppty=3,5-bis-（1H-pyrazol-3-yl）-[1,2,4]triazol-4-ylamine）。进一步的研究表明,1和2的结构分别包含有双核和四核镉簇单元,呈现出零维和二维的结构。并且在室温下对2个配合物的荧光性质也进行了测试。固体紫外漫反射表明1和2的光学带隙分别为1.87和2.32 eV,因此它们对亚甲基蓝的光降解反应表现出了良好的催化活性。     

氰基桥联的Fe2Ni双之字链的合成与磁性

利用四氰基构筑单元和不同位阻的吡啶类配体,合成了3例氰基桥联的Fe₂^ⅢNi^Ⅱ链状化合物。化合物{[Fe（bpy）（CN）₄]₂[Ni（bp）₂]·2H₂O}_n（1）（bpy=2,2''-联吡啶;bp=4-苯基吡啶）,{[Fe（bpy）（CN）₄]₂[Ni（papy）₂]·H₂O}_n（2）（papy=4-（苯基氮烯）吡啶）和{[Fe（bpy）（CN）₄]₂[Ni（azp）]·4H₂O}_n（3）（azp=1,2-二（吡啶-4-基）二氮烯）均为双之字型的链状结构。磁性测试表明化合物1~3均表现为链内的铁磁相互作用。化合物1表现出单链磁体行为,有效能垒为10.9 K。     

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%.     

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.     

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.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

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.