两个四唑配合物的原位合成、多样化配位模式和强荧光性质

在路易斯酸ZnCl₂或MnSO₄·7H₂O作用下,通过1-甲基-1-氢-咪唑-4,5-二甲腈与NaN3水热原位合成了2个四唑配合物:{[Zn₂(midt)(Hmidt)](N₃)·H₂,O}_n(1)和[Mn(midt)₂·(H₂O)₂]·H₂O(2)(midt=1-甲基-1-氢-咪唑-4,5-二四唑)。X射线单晶衍射表明尽管配合物1和2均结晶于同样的P1空间群,但他们有完全不同的结构。配合物1为一个有趣的二维聚合物结构,含有两个不同配位环境的锌原子和多种配位模式的midt配体,而配合物2为一个三维超分子结构,包含一个有趣的水分子链结构。固态下1和2分别在353和382 nm处显示出较强的蓝色荧光。     

喹啉和吡啶取代三芳基三唑的两个铜配合物的合成与晶体结构

分别以3-（2-吡啶基）-4-（4-甲基苯基）-5-（2-喹啉基）-1，2，4-三氮唑（L¹）和3-（2-吡啶基）-4-（4-氟苯基）-5-（2-喹啉基）-1，2，4-三氮唑（L²）作为配体，合成了2个新的单核铜配合物：trans-[Cu（L¹）₂（NO₃）（H₂O）]NO₃·H₂O（1）和trans-[Cu（L²）₂（NO₃）（H₂O）]NO₃·H₂O（2），对其进行了红外、元素分析和单晶结构表征。2个配合物都属于三斜晶系，P1空间群。单晶结构表明，配合物1和2中的铜离子均处于一个扭曲的八面体配位环境[CuN₄O₂]，轴向上各有一个水分子和一个硝酸根配位。配体的吡啶氮原子和三氮唑的一个氮原子参与配位，而喹啉的氮原子不配位。配合物晶体中存在O-H…O、C-H…O、C-H…N氢键和C-H…π相互作用，从而连接单核配合物形成三维网络。     

基于2-(4'-羧基苯基)咪唑-4,5-二羧酸构筑的三个镉/锌配位聚合物的合成、拓扑结构、荧光光谱及DNA作用

以2-（4''-羧基苯基）咪唑-4,5-二羧酸（H₄CPhIDC,C₁₂H₈N₂O₆）为配体,用溶剂热合成了3种配位聚合物{[Cd₂（CPhIDC）（bimb）]·H₂O}_n（1）、{[Cd₂（CPhIDC）（phen）₂]·3H₂O}_n（2）、{[Zn₂（CPhIDC）（bpp）]·1.5H₂O}_n（3）（bimp=1,4-双咪唑基-丁烷,phen=1,10-菲咯啉,bpp=1,3-双（4-吡啶基）-丙烷）。用元素分析、红外光谱、粉末X射线衍射和单晶X射线衍射对配合物进行了表征和结构分析。结构分析表明,主配体以完全去质子化CPhIDC^4-的形式与中心金属离子形成以μ₄和μ₅为配位模式的二维及三维聚合物。配合物1和3是三维网络结构,同时呈现（3,4,5）-连接的（5·6·7）（4·5²·6·7²）（4·5²·6·7⁴·8²）拓扑结构,两者的不同之处是中心离子和辅助配体。配合物2是二维波纹状渔网结构,呈现4⁴·6²拓扑结构,在其空间填充上又类似于DNA双螺旋链的单螺旋结构。测定了产物的固体荧光光谱;用EtBr荧光探针法研究了配体及配合物与ct-DNA的相互作用。     

两个由双咪唑基配体构筑的锰、镉配合物的合成及晶体结构

通过水热法合成了2个金属-有机配位聚合物[Mn（dipha）（1,3-bix）]_n·nH₂O（1）和[Cd₂（NIPH）₂（bimb）_2.5（H₂O）]_n·3nH₂O（2）（H₂dipha=2,2’-联苯二甲酸,1,3-bix=1,3-双（咪唑基-1-甲基）-苯,H₂NIPH=5-硝基间苯二甲酸,bimb=1,4-双（咪唑基-1-甲基）-丁烷）。并对其进行了元素分析、红外光谱、热重和X-射线单晶衍射测定。这2个配合物通过氢键和π-π相互作用形成了超分子网状结构。此外还研究了配合物2的荧光性质。     

由4-甲基-1，2，3-噻二唑-5-甲酸构筑的过渡金属配合物的合成、晶体结构及与DNA作用

以4-甲基-1,2,3-噻二唑-5-甲酸（C₄H₄N₂O₂S, HL）分别与硫酸钴（CoSO₄·7H₂O）、氯化铜（CuCl₂·2H₂O）、硝酸银（AgNO₃）反应合成了3个配合物[Co（L）₂（H₂O）₄] ·2H₂O （1）、[CuNa（L）₃] _n （2）和[AgL] _n （3）,用元素分析、红外光谱、热重分析进行表征,用单晶X射线衍射测定了产物的结构。配合物1属于三斜晶系,空间群P1,Co²⁺的配位数为6,形成一个略为拉长的CoN₂O₄八面体,与理想的正八面体非常接近。配合物2属于三斜晶系,空间群P1。Cu²⁺离子的配位数为4,构成变形的平面四边形结构,Na⁺离子的配位数为6,构成一个略微变形的八面体结构,最终形成三维网状结构。配合物3属于单斜晶系,空间群P2₁/c,银离子为三配位,构成变形的平面三角形构型,具有二维网状结构。用溴化乙锭荧光探针法测定了配体和配合物与DNA作用的荧光光谱。     

以四氟对苯二甲酸为配体构建的两个铅的配位聚合物：合成、晶体结构和荧光性质

在4-甲基咪唑/三氮唑存在下,利用四氟对苯二甲酸为配体、与Pb（NO₃）₂作用,得到了2种配位聚合物{[Pb（tfbdc）（H₂tfbdc）_0.5]·（4-MI）·（H₂O）}_n（1）和{[Pb（tfbdc）（H₂O）₂]}_n（2）（H₂tfbdc=四氟对苯二甲酸,4-MI=4-甲基咪唑）,并用红外光谱、元素分析和X-单晶衍射对其进行了表征。化合物1属于单斜晶系,空间群为P2₁/n,化合物2属于三斜晶系,空间群为P1。配合物1中,铅离子依靠正常的Pb-O键和次级键Pb…O,与7个氧原子配位;tfbdc^2-阴离子和H₂tfbdc分别采用不同的配位方式桥联铅离子,导致1个具有孔道的三维结构的形成。而4-甲基咪唑和游离水分子通过氢键作用嵌在这三维结构的孔道中。π-π堆积作用的存在增强了1的稳定性。配合物2中,铅离子是位于8个氧原子的配位环境中,tfbdc^2-阴离子以螯合和桥联的方式与铅离子作用,导致1个二维层状结构的形成。此外还考察了1和2的热稳定性和固体荧光性质。     

5-4-(1H-四唑基)苯氧基-间苯二甲酸构筑的镉配位聚合物的合成、晶体结构及荧光性质

以柔性配体为原料,在水热条件下合成了1个新的三维镉配位聚合物{[Cd₂L（OH）（H₂O）]·2H₂O}_n（1）（H₃L=5-4-（1H-四唑基）苯氧基-间苯二甲酸）,并对其进行了元素分析、红外、紫外、热重、荧光以及单晶X-衍射表征及研究。单晶衍射结果表明,配合物结晶于三斜晶系P1空间群。配合物中,相邻的Cd（1）和Cd（2）原子通过μ₃-桥联的羟基形成1个四核镉簇单元。相邻的四核簇二级构筑单元通过5-4-（1H-四唑基）苯氧基-间苯二甲酸连接形成三维结构。配合物1的荧光测试表明该化合物是1个潜在的蓝色发光材料。     

2-丙基-1H-4, 5-咪唑二酸构筑的混核锌-钕配位聚合物的合成、晶体结构及磁性质

通过水热方法,合成了一个杂金属的配位聚合物{[NdZn(H₂pimda)₃(Hpimda)(H₂O)₂]·H₂O}_n(1),(H₃pimda=2-丙基-1H-4,5-咪唑二酸),并对其结构和磁性质进行了研究。结构分析结果表明配合物1的晶体属于单斜晶系,P2₁/c空间群。配合物1是由配体2-丙基-1H-4,5-咪唑二酸连接而成的二维层状结构,该二维层通过氢键延伸为三维超分子结构。磁性研究表明,配合物1中相邻钕离子间存在着反铁磁相互作用。     

由2-甲基-4-噻唑甲酸构筑的过渡金属配合物的合成、晶体结构及与DNA作用

以2-甲基-4-噻唑甲酸（HMTZA,C₅H₅NO₂S）为配体合成了3种新型过渡金属配合物[Co（MTZA）₂（H₂O）₂]·3H₂O（1）,[Cu（MTZA）₂（H₂O）]·2H₂O（2）和[Zn（MTZA）₂（H₂O）₂]·3H₂O（3）。对配合物进行了元素分析、红外光谱和热重分析表征,用单晶X射线衍射方法测定了配合物的晶体结构。结果表明,配合物1属于单斜晶系,空间群为P2₁/n,中心金属Co（Ⅱ）离子的配位数为6,配位构型为略为变形的八面体;配合物2属于三斜晶系,空间群为P1,Cu（Ⅱ）离子的配位构型是一个畸变的四方锥;配合物3属单斜晶系,空间群为P2₁/n,中心金属Zn（Ⅱ）离子的配位构型为畸变的八面体。用溴化乙锭荧光探针法测定了配体和配合物与DNA作用的荧光光谱,结果显示无论配体还是配合物均能使EB-DNA复合体系发生不同程度的荧光猝灭,且配合物的作用强度远大于配体。     

锌、镉配位聚合物的合成、晶体结构及荧光性质

通过水热法合成了2个金属-有机配位聚合物[Zn（boba）（bix）]_n=（1）和[Cd（L1）（L2）]_2n=·nH₂O（2）（H₂boba=4,4’-（丁烷-1,2-二氧基）-二苯甲酸,bix=1,4-双（咪唑基-1-基）苯,H₂L1=4-（羧基甲氧基）苯甲酸,L2=2-（4-羟基）-1H-咪唑并[4,5-f][1,10]菲咯啉）。并对其进行了元素分析、红外光谱、热重和X-射线单晶衍射测定。配合物1为二维网状结构,配合物2为一维双链结构。此外,还研究了它们的荧光性质。     

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.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.