双臂型方酰胺多齿配体的合成

自1959年发现方酸以来,已有许多文献报道其可以与多种金属离子,尤其是过渡金属离子形成配合物,但方酰胺多齿配体的研究却不多。在方酰胺内鎓盐中,二氧环丁烯具有电荷分离特性,其上的氧原子带部分负电荷,是理想的配体原子。如果以它为中心,对称地引入具有配位能力的分子片段,如甘醇     

8-羟基喹啉取代大环配合物的酸分解动力学研究

合成了新型双功能化的8-羟基喹啉取代二氧四胺大环。这类新配体含有两个配位活性中心,在适当条件下,能分别与金属离子配位。根据pH电位滴定和紫外光谱实验的结果,在L(配体):M(金属离子)=1:1的情况下,8-羟基喹啉完全配位而二氧四胺大环只有部分配位,研究了在不同温度和不同酸度下8-羟基喹啉取代二氧四胺大环铜(Ⅱ)配合物酸催化的分解动力学行为。根据实验数据,提出了合理的反应机理。实验发现此类酸分解反应与以往二氧四胺大环酸分解机理有显著的不同,但大环的配位仍对该配合物的酸分解行为有很大的影响。     

溶液中N—乙酸基取代氮氧杂大环的构象及其配合物的NMR研究

用~1HNMR方法研究了溶液中大环化合物1,12-二氮杂-3,4:9,10-二本并-5,8-二氧杂环十五烷-N,N’-二乙酸盐的构象.NMR变温实验表明,在溶液中大环与Zn(Ⅱ)、Ni(Ⅱ)、Co(Ⅱ)的配合物环上醚氧不参与配位,其中Ni(Ⅱ)配合物为低自旋反磁性的平面四方形配位.     

N,N''''-二乙酸取代含噻吩环氮杂冠醚配体及其稀土配合物的合成与表征

N－功能化大环不仅环的空腔大小及环上配位原子种类对不同离子具有配位选择性，其功能化的官能团也会对大环配体的性质和选择性有很大影响，这类大环及其金属配合物，在药物试剂犤１犦，金属离子的分离与回收犤２犦，环境保护和新材料犤３犦等方面都有着广泛的应用前景。人们对N－功能化氮氧杂大环及其配合物研究较多犤４～６犦，而对N－功能化的氮氧硫杂大环研究并不多。为了进一步研究和开发这类大环配体及其性质，我们合成了一个新的功能化的大环配体（４，５：１４，１５二苯并－３，１６－二氧－２１－硫－７，１２－二氮双环犤１６…     

π-烯丙基氯化铁三吡啶配合物与丁烯醛反应的研究

丁烯醛在π-烯丙基氯化铁三吡啶配合物作用下,会生成自缩合产物,经色谱-质谱、红外光谱、核磁等手段表征,确认产物为6-甲基-1,3环已二烯基甲醛。推测反应机理是丁烯醛与π-烯丙基氯化铁三吡啶配合物进行配位体交换,然后与另一丁烯醛分子加成环化而成。由于配合物中配位体的定位作用,大大提高了反应的选择性而未见其它副反应发生。     

铜(II)-α,α'-联吡啶-二氧四胺大环三元体系的热化学性质

大环多腔的空腔为过渡金属离子提供了良好的配位环境，很多大环配合物都具有特殊的结构及性质．二氧四肢大环具有大环和肽的双重性质，是某些具有3d电子的二价金属离子的极好的螫合剂问．其配合物显示了一些特殊的性质和重要的生物功能．如作酶的模型、氧的载体等K和铜（11）配     

基于外壁作用的瓜环基超分子配位聚合物

利用瓜环外壁的结构导向作用设计并构筑瓜环-金属离子超分子配位聚合物可能成为瓜环配位化学研究的一个新方向。根据瓜环外壁作用类型,研究内容包括:1) 瓜环外壁取代烷基推电子效应对瓜环基超分子配位聚合物形成的促进作用;2) 瓜环外壁与化合物芳环的相互作用对瓜环基超分子配位聚合物形成的促进作用;3) 瓜环外壁与无机阴离子的相互作用对瓜环基超分子配位聚合物形成的促进作用;4) 瓜环外壁取代羟基的配位作用对瓜环基超分子配位聚合物形成的促进作用。这些瓜环基超分子配位聚合物可能具有吸附捕集、分离提纯和分析等功能性质。     

铁铬酸锌尖晶石催化剂的表面氧种

用TPR,TPO,TPD和脉冲反应等技术以及XRD,EPR和XPS等物理方法对铁铬酸锌尖晶石的表面氧种及其与丁烯-2的反应和吸附性能进行了考察,结果表明该尖晶石表面存在α-,β-和γ-三种氧种。α-氧为表面弱结合氧,主要参与丁烯的深度氧化和使丁烯形成表面滞留物。β-氧为尖晶石结构中与Fe~(3+)配位的表面晶格氧,它参与选择氧化生成丁二烯。γ-氧为α-Fe_2O_3中的晶格氧,在所考察的条件下(270℃)基本上不参与反应。认为在铁铬酸锌的尖晶石相中的铁离子和与它配位的表面晶格氧(即β-氧)构成选择氧化的活性位。在丁烯氧化脱氢反应中通过反应条件的选择来控制表面氧种的类型和它们之间的相对密度,有可能提高活性和选择性     

有机镧系金属络合物的研究(L)——Cp_2′SmI和Cp′SmI_2·2THF的合成和晶体结构测定

本文首次合成了含分子内氧杂原子配位的双-(2-甲氧乙基环戊二烯基)碘化钐CP_2′SmI(Ⅰ)(Cp′=CH_3OCH_2CH_2C_5H_4)及四氢呋喃溶剂化的2-甲氧乙基环戊二烯基二碘化钐Cp′SmI_2·2THF(Ⅱ)。络合物(Ⅰ)和(Ⅱ)经元素分析及质谱等鉴定。并得到了它们的单晶。结构研究表明,晶体(Ⅰ)属于P2_12_12_1空间群,晶胞参数:a=11.074(4)(?),b=12.929(9)(?),c=12.269(4)(?),(Ⅰ)中每个钐原子和两个环戊二烯基,二个醚基取代基上的氧原子和一个碘原子配位,形成单体结构,Sm(Ⅲ)的配位数为9。晶胞中含有4个单体分子,晶体(Ⅱ)属于P2_1/c空间群,晶胞参数:a=16.304(6)(?),b=8.335(2)(?),c=16.527(5)(?),β=111.8(1)°。晶体(Ⅱ)中每个钐通过一个环戊二烯基,一个醚基取代基上的氧原子,二个四氢呋喃的氧原子和二个碘原子配位形成单体结构,Sm(Ⅲ)的配位数为8。晶胞含4个单体分子。     

HZSM-5 分子筛上乙烯芳构化过程中 C4 至 C6 中间体的反应机理

 应用量子力学和分子力学联合的 ONIOM2 (B3LYP/6-31G(d,p):UFF) 方法, 采用包含分子筛孔道结构的 78T 簇模型, 对 HZSM-5 分子筛上乙烯芳构化过程中 C4 至 C6 中间体的反应历程进行了研究, 探讨了分子筛的酸催化机理和择形催化作用. 结果表明, 作为乙烯二聚产物的表面正丁基烷氧络合物 (C4) 直接与乙烯作用得到正己基烷氧络合物 (C6), 在分子筛孔穴尺寸的限制下, 很难实现碳链的折叠环化. 按照间歇反应历程, 丁基烷氧络合物先发生 C–O 键断裂, 脱质子生成 1-丁烯, 然后在酸性位上再与乙烯加成, 在分子筛表面生成 3-甲基戊基烷氧络合物. 该烷氧络合物脱除质子给分子筛, 同时环化生成甲基环戊烷, 后者再与分子筛酸性质子共同脱除氢分子, 生成不稳定的碳正离子中间体, 然后重构成环己烷正离子. 丁基烷氧络合物脱质子的活化能为 158.42 kJ/mol; 1-丁烯与乙烯加成反应的活化能为 130.71 kJ/mol; 3-甲基戊基烷氧络合物脱氢环化生成甲基环戊烷的活化能为 122.06 kJ/mol. 由于孔穴的限域作用, 五员环的甲基环戊烷是重要的中间体.     

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.     

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.     

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.     

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.     

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.     

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.