二维钴配位聚合物的构筑及对水中抗生素的吸附研究

利用水热法合成了[Co(ppda)(tib)]·4H2O配位聚合物。X单晶衍射分析表明，三链接体均苯三咪唑(tib)与钴离子配位构成二维网格面；顺式对苯二乙酸(ppda)与钴离子配位构成一维波浪线，并穿插于二维网格面，加强其稳固性；二维面之间通过π-π作用力形成复杂三维超分子网络结构。进一步研究了该配位聚合物作为吸附剂去除水中四环素(TEC)的行为与机理。结果表明，配位聚合物对四环素(TEC)的吸附量为51.394mg·g^-1；吸附数据与Langmuir模型和拟二级动力学方程具有更高的拟合程度，以此可判断吸附过程为单层化学吸附；主要的吸附作用力为配位聚合物与四环素的苯环之间的π-π相互作用；热力学研究说明该吸附是自发的吸热熵增过程。     

一维单链4-吡啶甲醛缩氨基硫脲合锌(ⅱ) 配位聚合物的合成、晶体结构及配体的新颖配位模式

4-吡啶甲醛缩氨基硫脲(HL)与醋酸锌反应得到了标题配位聚合物[Zn(HL)(CH3 COO)2 ·H2 O]n (1). 采用元素分析、红外光谱、紫外光谱和单晶X射线衍射测试技术对其结构进行了表征. 单晶X射线衍射分析表明,在标题配位聚合物1中,Zn 2 离子与1个配体HL中的吡啶环上的氮原子,另外1个配体HL中的硫原子以及2个醋酸根上的氧原子配位,构成了锌离子的畸变四面体构型;每个HL分别以吡啶环上的氮原子和硫原子以头对尾的方式与2个锌离子配位,从而将锌离子依次桥联,形成了类螺旋形链结构,链间通过氢键和π-π相互作用形成三维网络结构. HL潜在的NNS三齿配位点中亚胺N没有配位,吡啶N和S采取头对尾的NS配位模式是比较新颖的.     

含2-苯氧基丙酸根的镍、锌配位聚合物的合成与晶体结构

用溶液法和水热法分别合成了2个含2-苯氧基丙酸配体(HL)的聚合物{[NiL2(H2O)2(bipy)].2H2O}n(1)、{[ZnL2(bipy)].2H2O}n(2)(bipy=4,4′-联吡啶),用元素分析、红外光谱、热重和单晶X-射线衍射对产物进行了表征。在化合物1中,镍原子与2个羧基氧原子、2个配位水氧原子及2个4,4′-联吡啶的2个氮原子配位,配位数为6,镍原子的配位构型为畸变的八面体;而在化合物2中,锌原子与2个羧基氧原子及2个4,4′-联吡啶中的2个氮原子配位,锌原子的配位构型为畸变的四面体。在这2个化合物里,4,4′-联吡啶通过氮原子连接金属原子形成一维链状。链间氢键与π-π堆积作用又将一维链链接成二维层状结构。     

高氯酸镧与18—冠—6在乙腈溶液中配位反应的量热滴定研究

用量热滴定法于298.15K测定了高氯酸镧与18—冠—6在无水乙腈溶液中的配位作用.(?)助计算机求得了配合物的稳定常数和配位焓,进而算出了配位自由能和配位熵.配位反应为放热反应.     

β-羰基酰胺类化合物的配位及晶体结构

为确认β-羰基酰胺类化合物与铜离子的配位位点,合成了6种β-羰基酰胺类配体L1～L6,分别与Cu(Ⅱ)进行配位反应.对生成的配合物进行单晶培养,并采用X射线衍射仪测定了单晶结构.结果表明,只有配体L6(2-苯甲酰乙酰苯胺)的铜配合物能够得到单晶.在其单晶中,Cu(Ⅱ)离子与来自2个配体的4个氧原子配位形成长方形的构型;配合物中存在分子内氢键、分子间氢键和π-π相互作用.     

基于ZnTMPP一维线性配位聚合物的合成及其光、电性能

以四(对甲基苯基)卟啉锌(ZnTMPP)配合物为核心配体,选择联吡啶、联苯胺和新合成的Schiff碱-双(4-吡啶甲醛)缩联苯胺为桥联配体合成了3种新型π-π共轭的一维线性配位聚合物。通过FT-IR、1 H-NMR、UV-Vis-NIR和XRD衍射谱图等对配体及配位聚合物结构进行了表征。考察了桥联配体的长度及结构对配位聚合物光学性能、电性能和结晶态的影响。结果表明,以Schiff碱-双(4-吡啶甲醛)缩联苯胺为桥联配体合成的配位聚合物在300~1 100nm有宽吸收带,并且可在低电位发生氧化还原反应,其满带和空带之间的能隙为0.19eV;以联吡啶和联苯胺为桥联配体的配位聚合物结晶度较好。     

新型钠配位聚合物的合成、表征及其晶体结构

用溶液法合成了未见报道的2-氨基-5-硝基苯甲酸钠配位聚合物,并得到晶体.通过红外光谱、元素分析、X-射线单晶衍射偷和循环伏安法对钠配位聚合物的结构和电化学性质进行表征和研究.测试结果表明,标题钠配位聚合物属单斜晶系,空间群P21/n,晶胞参数为a=0.681 30(7)nm,b=0.692 22(8)nm,c=2.068 83(18)nm,α=90.00°,β=94.877 0(10)°,γ=90.00°,V=0.972 15(17)nm3,Z=4,Dc=1.641g·cm-3,F(000)=496,钠配位聚合物是通过弱π-π堆积作用自组装成二维层状超分子结构,在循环伏安图上出现一对氧化还原峰.     

基于2-氨基对苯二甲酸的镉配位聚合物的合成、晶体结构和性质研究

以2-氨基对苯二甲酸根离子(AT)为配体,合成了3个结构新颖的镉配位聚合物:[Cd(AT)(H2O)]n(1)、[Cd(AT)(Py)]n(2)和[Cd(AT)(BPP)]n(3)(AT=2-氨基对苯二甲酸根离子,Py=吡啶,BPP=1,3-二(4-吡啶基)丙烷)。晶体结构表明,随着辅助配体的改变,AT表现出3种不同的配位模式,分别形成rtl(1)、ths(2)和sql(3)3种不同的拓扑结构。由于分子内/分子间氢键、芳香环之间的π…π堆积与C-H…π相互作用,使得3个化合物展现出较好的热稳定性。     

基于阴离子调控策略的Co(Ⅱ)配位聚合物的合成、晶体结构及荧光性质

以三键桥联吡啶类配体2,6-二(3′-吡啶乙炔基)-4-甲基苯胺(L)为配体,在常温混合溶剂(二氯甲烷-甲醇)中分别与CoCl_2、Co(SCN)2通过自组装反应,获得了一维及二维配位聚合物[Co(L)Cl_2]_n(1)及[Co(L)_2(SCN)_2]_n(2),通过红外、元素分析、X射线单晶衍射等检测手段对所合成的配合物进行了结构表征。对比1和2的单晶结构可以发现,配体L在配位聚合物1和2中的配位取向及结构相似,不同的是Co(Ⅱ)离子的配位数受配位阴离子的影响而不同:配位聚合物1中四配位的Co(Ⅱ)通过2个配体的相互连接呈现一维的弯曲链状结构,而配位聚合物2中六配位的Co(Ⅱ)则通过4个配体的相互连接得到二维的平面结构。2个配合物中均存在氢键及π-π相互作用。通过粉末衍射证明了配位聚合物1和2为单一晶相,其固态下的荧光测试显示,二者的荧光均减弱,并相对于配体L有红移(1)及蓝移(2)。     

配位聚合物[Cd2(BDC)2(obix)2]·H2O的合成、晶体结构和荧光性质

用水热合成方法得到1个新的配位聚合物[Cd2(BDC)2(obix)2]·H2O(H2BDC=对苯二甲酸,obix=1,2-(二亚甲基)二咪唑).配合物晶体属三斜晶系,P1空间群.晶体结构表明:镉原子与3个对苯二甲酸上的5个氧原子,2个1,2-(二亚甲基)二咪唑中的2个氮原子配位形成扭曲的五角双锥配位构型.2个Cd(Ⅱ)原子通过两个羧基桥联形成一个双核Cd2单元,再通过配体连接成二维层状结构,层与层之间通过C-H…O氢键和弱的π-π相互作用形成三维超分子结构.室温下配合物具有较强的荧光发射光谱.     

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.