一种镉基金属有机骨架材料对丙酮和Fe3+的荧光检测

以 1，3，5-三(4-羧基苯基)苯(H₃BTB)为配体，通过溶剂热法得到一种三维四重穿插结构的镉基金属有机骨架材料：(Me₂NH₂)[Cd(BTB)(DMF)]·DMF·H₂O(Cd-MOF)。通过单晶X射线衍射、粉末X射线衍射、红外分析、元素分析和热重分析表征了其组成和结构。荧光研究结果表明：Cd-MOF在含有丙酮或 Fe³⁺离子的溶液中均表现出荧光猝灭现象，其检测限(体积分数和浓度)分别为0.6%和0.89 μmol·L^-1，线性检测范围分别为2.0%~2.8%和0~0.05 mmol·L^-1。时间响应实验和可循环利用实验显示Cd-MOF可长时间、稳定且高效地检测丙酮和Fe³⁺离子。     

一例互穿的阴离子型In（Ⅲ）金属有机骨架用于选择性检测水中Fe3+离子

作为一类新型多孔材料,金属有机骨架（MOFs）常被开发作为荧光传感器用来监测水中的污染物,开发稳定且易制备的MOFs材料实现选择性检测有毒的Fe³⁺仍具有较高挑战。本工作中,我们报道一例水稳定的二重穿插In（Ⅲ）基MOF：（NH₂Me₂）[In （fdc）₂]·2H₂O （BUT-205,BUT代表北京工业大学,H₂fdc=呋喃-2,5-二羧酸）。BUT-205的构筑采用生物质衍生配体,其结构通过单晶X射线衍射确立。这个材料可作为高效的水相Fe³⁺离子传感器,具有高的灵敏度和选择性。检测限达到1.3 μmol·L^-1,低于美国环保局规定的饮用水中安全标准（15.7 μmol·L^-1）,并且该传感材料可以回收利用至少4次。     

含共轭三烯吡啶配体的配位聚合物的合成、结构及荧光性质

将1,6-双（4-吡啶基）-1,3,5-己三烯（bphte）和镉盐分别与2种羧酸配体（2,5-二呋喃二甲酸（2,5-H₂FDC）及1,3,5-均苯三甲酸（1,3,5-H₃BTC））进行溶剂热反应,得到2个配位聚合物：[Cd （2,5-FDC）（bphte）（H₂O）]_n （1）和[Cd （1,3,5-HBTC）（bphte）]_n （2）。对配合物1和2分别进行了元素分析、红外光谱、单晶X射线衍射、粉末X射线衍射和热重分析表征。配位聚合物1具有spl拓扑结构的三维互穿超分子框架,而配合物2是由bphte配体交叉连接一维链[Cd₂（1,3,5-HBTC）₂]_n形成的三维结构。配合物1和2在固态时表现出不同的荧光性质。配合物2遇到水溶液中Fe³⁺会发生荧光猝灭,因此以其作为荧光探针对水溶液中Fe³⁺进行了选择性荧光检测,它对Fe³⁺的检测限可达到0.013 μmol·L^-1。这种荧光猝灭过程可归因于Fe³⁺离子的吸收带与配合物2的激发带之间存在部分重叠。     

异核Ln(Na)-MOFs(Ln=Tb、Dy、Ho)的晶体结构及对乙醛、Fe3+、Cr2O72-的荧光传感和邻苯二酚的电化学传感

在溶剂热条件下合成了3个新型三维微孔同构异核金属有机骨架Ln （Na）-MOFs：{[LnNa （BDT）（H₂O）₃]·2H₂O}_n（Ln=Tb （1）、Dy （2）、Ho （3）,H₄BDT=3,5-二（3'',5''-二羧基苯基）-1H-1,2,4-三唑）,并通过单晶X射线衍射、元素分析、热重分析和粉末X射线衍射技术对其进行表征。结构分析表明,Ln （Na）-MOFs是具有相同的异核双金属单元的三维骨架结构。荧光研究表明,Tb （Na）-MOF （1）可以荧光传感检测水中Fe³⁺、Cr₂O₇^2-以及乙醛分子,具有较高的灵敏度和选择性,也可用于水中邻苯二酚的电化学检测。     

一个富路易斯碱位配合物的合成、结构及对痕量Ag+的荧光检测

通过溶剂热方法合成了一个由氢键拓展的携带路易斯碱位的三维超分子配位聚合物：{[Cd（HTZ-IP）（HPYTZ）（H₂O）₂]·5H₂O}_n（HTZ-H₂IP=5-（5-四氮唑基）间苯二甲酸;HPYTZ=3,5-（4-吡啶基）-1,2,4-三唑]。X射线单晶衍射结果表明,中心镉离子由含氮杂环羧酸配体和富氮辅助配体连接成"有悬挂手臂"的一维链,而链间则凭借配位水和2个配体的氢键作用拓展成三维超分子化合物。有趣的是配合物存在大量裸露的未配位的N原子,此N原子具有路易斯碱性质,能与路易斯酸性质的Ag⁺有效结合,从而引起配合物的荧光猝灭。该性质能在无色溶液中有效检测10^-4~10^-6 mol·L^-1范围内的痕量Ag⁺离子。     

一个对2,4,6-三硝基苯酚和Fe3+离子具有双重荧光传感行为的层状镉(Ⅱ)-有机配位聚合物

通过水热法合成了一个由三连接的2,3-喹啉二甲酸桥联扭曲的Cd²⁺八面体形成的二维层状配位聚合物[Cd（QDA）]_n（1）。该配合物发射出较强的蓝色荧光并具有很高的热稳定性和化学稳定性。更为重要的是,该配合物在乙醇分散体系中可快速识别痕量的2,4,6-三硝基苯酚和Fe³⁺离子,其对2,4,6-三硝基苯酚的淬灭常数（K_sv）和检测限（LOD）分别为6.61×10⁴ L·mol^-1和0.83 μmol·L^-1,对Fe³⁺离子的淬灭常数和检测限分别为1.74×10⁴ L·mol^-1和2.70 μmol·L^-1。     

基于多金属氧酸盐和多壁碳纳米管的双酚A电化学传感器的构建与性质

选择含N配体（L=1,3-双（1-咪唑）丙烷）与磷钼酸（H₃PMo₁₂O₄₀）水热合成了一个新的无机-有机杂化化合物（H₂L）₂（HL）₂L （PMo₁₂O₄₀）₂·2H₂O （PMo₁₂）。通过红外、热重、X射线光电子能谱、X射线粉末衍射和单晶衍射等对该化合物进行了表征。X射线单晶衍射表明该化合物为3D结构。将该化合物和多壁碳纳米管修饰在玻碳电极上构造了一种双酚A电化学传感器并对其传感性能进行研究。研究表明,在1~20 μmol·L^-1范围内,检出限为0.5 μmol·L^-1（S/N=3）,并且该传感器具有良好的抗干扰和稳定性。     

一种用于选择性检测苯乙烯的Zn-MOFs发光传感器

在溶剂热条件下合成了一种新型金属有机框架（MOF）{[Zn₂（tyia）₂（H₂O）₂]·H₂O}_n（1）,其中H₂tyia为5-（1H-1,2,4-三唑-1-基）间苯二甲酸。运用X射线单晶衍射分析其结构,通过元素分析、粉末X射线衍射、热重分析、固体荧光分析等手段对配合物1进行表征,研究了其与有机小分子相互作用的荧光特性。结果表明其能够对低浓度苯乙烯迅速做出反应,最低识别浓度为1.06 mmol·L^-1。此外,还对其传感机制进行了研究。     

基于香豆素Schiff碱的Zn2+、Co2+和Ni2+配合物的合成、晶体结构及光谱性质

合成了3个香豆素Schiff碱单核Zn²⁺、Co²⁺和双核Ni²⁺的配合物，[Zn（L¹）₂]（1）（HL¹=6-（（4-二乙胺基-2-羟基-亚苄基）-氨基）-苯并吡喃-2-酮），[Co（L²）₂]（2）（HL²=6-（（4-甲氧基-2-羟基-亚苄基）-氨基）-苯并吡喃-2-酮），[Ni₂（L³）₂（CH₃OH）₄）]（3）（H₂L³=4-羟基-3-（（4-甲氧基-2-羟基-亚苄基）-氨基）-苯并吡喃-2-酮）。利用元素分析、红外光谱、紫外可见光谱、荧光光谱及X射线单晶衍射分析等手段对其进行了表征。X射线单晶衍射分析结果表明：配合物1和配合物2均为单核结构，由1个金属离子和2个配体单元组成；配合物3具有双核结构，由2个金属离子、2个配体单元及4个配位的甲醇分子组成。配合物1、2和3分别是单斜晶系、三斜晶系和三斜晶系，所属的空间群分别为C2/c、P1和P2₁/n；中心金属Zn²⁺和Co²⁺离子的空间构型为四配位的四面体，Ni²⁺离子的空间构型为六配位的扭曲的八面体。此外，通过对配体HL¹和HL²的紫外可见光谱性质研究发现，在DMF/H₂O（4：1，V/V）溶液中，自由配体HL¹和HL²分别可以选择性识别Hg²⁺和Zn²⁺，通过计算得到其检测限分别为7.45和6.10 μmol·L^-1。荧光性质研究发现在DMF/H₂O（4：1，V/V）溶液中自由配体HL²可以检测Zn²⁺，检测限为2.91 μmol·L^-1。     

多功能Zn（Ⅱ）金属有机骨架荧光传感器检测苯甲醛、四环素、2，4，6-三硝基苯甲酸、氟啶胺、Cr2O72-和Fe3+

成功制备了新型Zn（Ⅱ）金属有机骨架(MOF)[Zn₂(Hdepa)(dya)₂]_n (1)(H₅depa=2,2'',3,4'',5-二苯醚五羧酸,dya=2,2''-二吡啶胺)。单晶X射线衍射分析表明MOF 1由2个Zn²⁺离子与1个Hdepa^4-离子和2个dya分子连接组成,通过氢键形成三维骨架。用粉末X射线衍射和IR表征了配合物1的相纯度。值得注意的是,配合物1具有优异的荧光特性和热稳定性,1的高灵敏度和选择性使其能够作为荧光传感器检测苯甲醛(BZH)、四环素(TC)、2,4,6-三硝基苯酚(TNP)、氟啶胺(Flu)、Cr₂O₇^2-和Fe³⁺。此外,通过荧光寿命分析了Fe³⁺、TC、BZH对MOF 1的荧光的猝灭过程,通过能量转移研究了Fe³⁺、Cr₂O₇^2-、TNP、TC、BZH和Flu的荧光猝灭机理。     

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.     

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.     

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.     

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.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

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.     

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.