4-羟基吡啶-2, 6-二甲酸铽配位聚合物的合成与光谱性能研究

在水热条件下合成了一个二维稀土铽的配位聚合物[Tb(cam)(H₂O)₃]_n·nH₂O) (1)(H₃cam=4-羟基吡啶-2,6-二羧酸),通过元素分析、红外光谱、X-射线单晶衍射、荧光、紫外吸收、热重分析和X-射线粉末衍射对其进行表征。Tb(Ⅲ)离子八配位呈十二面体几何构型。每个Tb(Ⅲ)离子与3个(cam)^3-离子相连形成具有(4·8²)型拓扑的二维层状结构,层与层之间通过氢键的识别作用拓展为三维超分子结构。室温下配合物1呈现出稀土Tb³⁺的特征荧光发射峰,且发光强度较大,说明配体的能级与TbⅢ离子的发射能级比较匹配。     

基于苯并咪唑-5-羧酸和对苯二甲酸配体构筑的二维镉配位聚合物的合成、晶体结构及荧光性质(英文)

水热条件下利用苯并咪唑-5-羧酸,1,4-对苯二甲酸和Cd(NO3)2·4H2O为反应物合成出了一个配位聚合物{[Cd(Hbic)(bdc)1/2]·H2O}n(1),并分别用元素分析,红外谱图,热重分析,X-射线粉末衍射和X-射线单晶衍射对其结构进行表征。结构分析表明该化合物为二维层状结构,其中每个独立的层都是由两种芳环羧酸配体连接链状的[Cd(COO)]n次级构筑单元所构成,有趣的是在二维层中还存在着笼状的空腔结构。邻近的二维层之间通过分子间氢键和π-π堆积作用进一步扩展为三维超分子结构。荧光谱图表明常温固态下配合物1发射绿色荧光,最大发射峰位于506 nm。     

稀土配位聚合物{(H_2prz)[Ln_2(pzdc)_4(H_2O)_2]·5H_2O}_n(Ln=Eu,Tb)的合成、结构和性质

以Ln(NO3)3、H2pzdc(2,3-吡嗪-二羧酸)和prz(哌嗪)为原料,在水热条件下得到了2个结构新颖的稀土配位聚合物{(H2prz)[Ln2(pzdc)4(H2O)2]·5H2O}n(Ln=Eu(1),Tb(2))。对它们进行了元素分析、红外光谱、粉末X-射线衍射、热重等分析,并用X-射线衍射测定了它们的单晶结构。2个配合物的晶系都属于三斜晶系,P1空间群。研究了它们的荧光性质,固体荧光实验测试结果表明,2个配合物在室温下均表现出相应稀土离子的特征荧光发射。     

以2-氯苯甲酸、5,5′-二甲基-2,2′-联吡啶构筑的双核铽配合物的晶体结构和荧光性质

水热条件下采用Tb(NO3)3.6H2O,2-氯苯甲酸和5,5′-二甲基-2,2-联吡啶作为反应物合成出一个双核铽金属配合物Tb2(2-cb)4(dmpy)2(NO3)2(2-cb=2-氯苯甲酸,dmpy=5,5′-二甲基-2,2′-联吡啶)(1),并分别用元素分析,红外光谱图,差热分析和X-射线单晶衍射等表征了该结构。晶体结构分析结果表明:化合物1为双核铽髥配合物,通过分子间的C-H…O氢键作用,双核分子进一步被连接成二维平面结构。热稳定性表明化合物1能够稳定到280℃;荧光分析表明常温固态下配合物1发射绿色荧光,荧光寿命为431.8μs。     

以4’-羟基-联苯-4-羧酸和1,3-二(4-吡啶基)丙烷构筑的一维锌配位聚合物的晶体结构与荧光性质

水热条件下采用Zn(NO3)2.6H2O,4′-羟基-联苯-4-羧酸和1,3-二(4-吡啶基)丙烷作为反应物合成出一个新的一维锌金属配位聚合物{[Zn(Hhbc)2(bpp)].H2O}n(1)(Hhbc=4′-羟基-联苯-4-羧酸,bpp=1,3-二(4-吡啶基)丙烷),并分别用元素分析、红外光谱、差热分析、X-射线粉末衍射和X-射线单晶衍射等表征了该结构。晶体结构分析结果表明:化合物1为一维链状锌(Ⅱ)配位聚合物,通过分子间的O-H…O氢键作用,一维链进一步被连接成二维超分子结构。荧光分析表明常温固态下配合物1发射蓝色荧光,荧光寿命为3.08 ns(480 nm)。     

三个低维Zn~Ⅱ-二膦酸配位聚合物的合成、结构及荧光性能研究

通过引入第二配体2,2′-联吡啶(2,2′-bipyridine,bipy),在水热条件下得到3个低维ZnⅡ-二膦酸配位聚合物:[Zn1.5(H2L)(bipy)(H2O)]·3H2O(1),[Zn(H3L)(bipy)]2(2),[Zn(H3L)(bipy)(H2O)]·H2O(3)(H5L=1-羟亚乙基-1,1-二膦酸,CH3C(OH)(PO3H2)2)。采用单晶X-射线衍射、粉末X-射线衍射(PXRD)、红外光谱(IR)、元素分析、热重(TG-DSC)等测试手段对产物的结构进行了表征。单晶X-射线衍射数据分析表明化合物1为一维梯形双链结构,结构中含有2个晶体学独立的锌离子,分别以四配位和六配位模式与配体连接。化合物2为O-P-O双桥连接三角双锥[ZnO3N2]而成的双核零维结构。化合物3为八面体[ZnO4N2]通过O-P-O单桥连接而成的一维链状结构。氢键和π-π堆积作用进一步将3个低维ZnⅡ-二膦酸化合物扩展为三维超分子。对化合物1~3进行荧光性能的研究,测试结果表明,3个化合物均发射出强度远大于配体bipy的荧光发射峰(λem=374nm(1)、388nm(2)、387nm(3),λex=252nm),该峰来源于第二配体bipy(λem=391nm,λex=252nm)分子内部的π*-π电荷转移。电化学测试结果显示3个化合物均表现出一步单电子氧化还原过程,与自由配体相比给电子能力增强,未来可作为空穴传输材料在光电领域得到应用。     

4-氯苯氧乙酸和1,10-邻菲啰呤构筑的双核铽配合物的晶体结构,荧光和生物活性(英文)

水热条件下采用Tb(NO3)3·6(H2O),4-氯苯氧乙酸和1,10-邻菲啰呤作为反应物合成出1个双核铽配合物[Tb2(4-Hcpoa)5(phen)2(NO3)](1)(4-Hcpoa=4-氯苯氧乙酸,phen=1,10-邻菲啰呤),并分别用元素分析、红外光谱、差热分析、X-射线粉末衍射和X-射线单晶衍射等表征了该结构。晶体结构分析结果表明:2个双齿和2个三齿4-氯苯氧乙酸配体将2个铽金属离子连接成二聚体结构。荧光分析表明常温固态下配合物1发射绿色荧光,且在544 nm处的荧光寿命为0.920 ms。以除草剂精喹禾灵为对照品,研究了配体4-氯苯氧乙酸及其配合物1对甘蓝型油菜和钝芒稗的抑制作用。     

基于5-(3′,4′-二(四唑-5′-基)苯氧基)间苯二甲酸构筑的镧系金属配合物的合成、晶体结构及性质（英文）

在水热条件下利用H_2btpa配体合成了2个镧系金属配合物{[Ln(btpa)(H_2O)(OH)]·bpy}n(Ln=Tb(1),Pr(2),H2btpa=5-(3′,4′-二(四唑-5′-基)苯氧基)间苯二甲酸,bpy=4,4′-联吡啶),并用元素分析、红外光谱、X射线粉末衍射、X射线单晶衍射对其进行了表征。配合物1和2中,双核镧系金属单元通过btpa2-配体以μ4:η1,η2,η1,η2的配位模式连接,形成二维网状结构,客体分子4,4′-联吡啶通过分子间的氢键作用存在于结构中。相邻的二维网通过氢键的识别作用以锁链形式拓展为三维超分子结构。室温下配合物1呈现出TbⅢ的特征荧光发射峰。     

异烟酰胺基间苯二甲酸根构筑的混核镍-铽配合物的合成、晶体结构及荧光性质

水热合成了一个的杂金属配合物{[NiTb2(INAIP)4(H2O)6].8H2O}n(1)(INAIP2-=异烟酰胺吡啶基异酞酸根),并对其进行了元素分析、IR及X-射线衍射法表征。晶体结构研究表明:配合物1属于三斜晶系,P1空间群。配合物1是由配体异烟酰胺吡啶基异酞酸连接而成的二维双层状结构,该二维层通过氢键延伸为三维超分子结构。荧光测试研究表明配合物1具有典型的稀土铽离子绿色荧光。     

以草酸、碳酸根构筑的一个钕(Ⅲ)配位聚合物的晶体结构和荧光性质

水热条件下采用Nd2(CO3)3和草酸钠作为反应物合成出一个新的三维钕(Ⅲ)配位聚合物{[Nd2(ox)(cb)2(H2O)2]·3H2O}n(1)(ox=草酸,cb=碳酸),并分别用元素分析、红外光谱、差热分析、X-射线粉末衍射和X-射线单晶衍射等表征了该结构。晶体结构分析结果表明:μ2桥联的草酸根离子与μ4桥联的碳酸根离子将钕离子连接成三维微孔结构,沿b轴和c轴方向分别具有孔径大小为0.53 nm×0.41 nm和0.59 nm×0.84 nm的通道。拓扑分析结果表明化合物1为(4,5)连接类型。荧光分析表明常温固态下配合物1发射近红外荧光。     

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.     

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 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.     

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.     

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.     

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.     

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.