由氢键构筑的两个超分子化合物的合成与结构

本文通过质子化内消旋大环配体[meso-H2L]^2＋及其外消旋镍配合物[Ni（rac-L）]^2＋与金属氧酸离子（[VO3]^-/[CrO4]^2）在水溶液中进行超分子组装得到两个氢键连接的超分子化合物[Ni（rac-L）]3[CrO4]2[ClO4]2·4H2O（1）和[meso-H2L][VO3]2·0.33H2O（2）.通过IR、元素分析、X-ray单晶衍射、热重等对其结构进行了表征.化合物1由[Ni（rac-L）]^2＋与CrO4^2-和水分子通过大环中的胺分子与CrO4^2-和水分子形成的氢键组成一维六方棱柱状结构.化合物2则由[VO3]n^n-阴离子螺旋链通过分子间氢键连接[meso-H2L]^2＋构成具有一维疏水通道的三维超分子化合物.研究结果表明氢键在超分子组装中起着重要的作用.     

两个基于多金属氧酸盐和水杨醛缩氨基硫脲的有机-无机杂化配合物的合成与晶体结构

采用自然蒸发法,合成了2个新颖的有机-无机杂化配合物[C_8H_6N_3S]_2[H_2Mo_2O_7](1)和[CoⅡ(C_8H_8N_3OS)_2]_2[H_3PW_(12)O_(40)]·4DMF(2),并对其进行了元素分析、IR、TG和单晶X-射线衍射表征.结果表明:化合物1是由1个双核多阴离子[H2Mo2O7]2-与2个有机组分[C_8H_6N_3S]+通过共价键形成的一维链状结构;化合物2是由水杨醛缩氨基合钴与DMF分子及多酸阴离子通过氢键作用形成的三维网状结构,其中水杨醛缩氨基硫脲合钴呈风车型.     

包含银的Keggin型锗钼酸盐[NH_4]_2[Ag(H_2O)(H_2PDCA)]_2[α-GeMo_(12)O_(40)]·12H_2O（英文）

利用常规水溶液方法合成了一种有机-无机杂化的包含银的Keggin型锗钼酸盐[NH_4]_2[Ag(H_2O)(H_2PDCA)]_2[α-GeMo_(12)O_(40)]·12H_2O(1),并通过元素分析、红外光谱和单晶X射线衍射等对其进行了表征.X射线晶体学研究表明化合物1的分子结构由1个典型的Keggin结构[α-GeMo12O40]~(4-)聚阴离子、2个[Ag(H_2O)(H_2PDCA)]~+配离子、2个NH+4离子和12个结晶水分子构成.值得注意的是在[α-GeMo_(12)O_(40)]~(4-)单元中,锗原子呈现出立方体几何配位构型,这归结于与锗原子相连的每个氧原子都无序地排列在两个位置.有趣的是,每个[α-GeMo_(12)O_(40)]~(4-)多阴离子通过4个[Ag(H_2O)(H_2PDCA)]~+桥配离子与4个[α-GeMo_(12)O_(40)]~(4-)多阴离子相连构筑了二维层状结构.此外,我们还在室温下研究了化合物1的电化学性质.     

含有5-甲基-3-吡唑甲酸的铅(Ⅱ)配合物:合成、结构和荧光性质

在不同含N辅助配体的存在下,将5-甲基-3-吡唑甲酸(H_2MPCA)与相应的铅(Ⅱ)盐反应制得了2个新的配合物:[Pb(HMPCA)_2(H_2O)_2]·H_2O (1)和[Pb(HMPCA)_2(phen)]·H_2O (2)(phen=菲咯啉)。双核配合物1中双核[Pb(μ_2-HMPCA)]_2单元在一对Pb…O次级键的作用下形成了一维链状结构,这些一维链在氢键的作用下进一步自组装成2D超分子结构。而单核化合物2在Pb…O次级键的作用下形成了Pb_2O_2平面,它们在π…π和氢键作用下堆积形成3D超分子结构。考察了配合物1和2的热稳定性、荧光性能。     

单一配体与混合配体协同构筑的一系列多酸基化合物:结构、电化学及选择性光催化性能研究

通过使用吡嗪(pz)及其衍生物2,3-萘吩基-苯并吡嗪(npz)和2,3-二苯基-苯并吡嗪(dpz),水热合成了1个基于Lindqvist型和6个Keggin型多酸的化合物,该系列化合物由单一配体或混合配体共同修饰多阴离子而构筑:[Ag~I_2(npz)_4(W_6O_(19))]·(npz)(1),[Ag~I_2(npz)_3(HPW_(12)O_(40))](2),[Ag~I_3(npz)_4(PMo_(12)O_(40))](3),[Ag~I_4(pz)_5(SiMo_(12)O_(40))](4),[Ag~I_4(npz)_2(pz)(PMo~VMo_(11)~(VI)O_(40))](5),[Ag~I_4(npz)_4(dpz)_2(SiW_(12)O_(40))(H_2O)_2](6),{Ag~I_5K~I_2(npz)_4(dpz)_2[H(PW~VW_(11)~(VI)O_(40))_2]}(7),并用X射线单晶衍射表征了它们的结构.化合物1中包含一个扭曲的"I"型的[Ag(npz)_2]~+亚单元,其中两个npz相互垂直.两个[Ag(npz)_2]~+亚单元对称的支撑在[W_6O_(19)]~(2-)阴离子上.在化合物2中,由一个二配位连接型和两个单配位终端npz配体构筑[Ag_2(npz)_3]~(2+)簇,该簇由[PW_(12)O_(40)]~(3-)进一步连接形成"日出"型链.化合物3中包含一个孤立的[Ag_2(npz)_3]~(2+)簇和一个单支撑的多阴离子[Ag~I(npz)(HPW_(12)O_(40))]~-.化合物4展示了一个蜂窝状的Ag-pz层,包含两种环路:六元环I和八元环II.多酸阴离子靠Ag连接形成的多酸二聚体,并倾斜嵌入较大的环路II中.在化合物5中,1个pz和2个npz被4个Ag~I连接形成一个直线型的[Ag_4(npz)_2(pz)]~(4+)亚单元.PMo_(12)多阴离子交替连接链状亚单元从而构筑一个一维链结构.化合物6中存在孤立的[Ag_2(npz)_2(dpz)(H_2O)]~(2+)亚单元和多阴离子.化合物7中,Keggin-K无机链被Ag~I-npz-dpz亚单元连接形成一个二维层.相邻层被多阴离子进一步连接构筑三维框架.此外,还研究了该系列多酸基化合物的电化学和光催化性质.     

基于2-(4-噻唑基)苯并咪唑配体和Cu~Ⅱ构筑的2个新的多酸基化合物

基于刚性配体2-(4-噻唑基)苯并咪唑和二价金属铜离子在水热条件下成功地合成了2个Keggin型多酸化合物[Cu~Ⅱ(L1)2(H_2O)]2[SiW_(12)O_(40)](1)和[(L_1)4(L_2)2(H_3PMo_(12)O_(40))_2]·5H_2O(2)(L1=2-(4-噻唑基)苯并咪唑,L_2=苯并咪唑).通过单晶X-射线、红外光谱和元素分析对化合物1和2进行了表征.在化合物1中,存在2个独立的结构单元:Keggin型多酸和蝴蝶状的络合物阳离子[Cu(L_1)_2(H_2O)]~(2+).化合物2为含有混合配体的超分子结构,由Keggin型多酸、4个游离的L_1和2个L_2配体组成.此外,研究了化合物1和2的电化学和光催化性能.     

一例基于Keggin型多酸阴离子的双加帽杂多铌酸盐的合成、结构及表征

在水热条件下,成功合成了一例基于Keggin型多酸阴离子的双加帽杂多铌酸盐[Ni(en)_3]_3[Ni(en)_2(H_2O)_2]_2H[VNb_(12)O_(40)(VO)_2]·10H_2O(1),并通过红外光谱、热重分析和X射线单晶衍射等方法对该化合物进行了表征.X射线单晶衍射分析表明,化合物1属于正交晶系,Pna2(1)空间群,晶胞参数a=3.051 7(3)nm,b=1.561 0(1)nm,c=2.271 9(3)nm,V=10.823(3)nm~3.化合物1包含1个Keggin型聚阴离子[VNb_(12)O_(40)(VO)_2]~(11-)和3个镍配离子.在阴离子结构中,中心钒原子被12个铌原子包围形成经典Keggin型结构的[VNb_(12)O_(40)]~(15-)阴离子,另外两个{VO}基团分别加帽于[VNb_(12)O_(40)]~(15-)阴离子的两端.     

两个含1-苄基咪唑的Zn(Ⅱ)和Cu(Ⅱ)新配合物:合成和结构研究(英文)

1-苄基咪唑(L)与对苯二甲酸和Zn(NO_3)_2·6H_2O反应生成一维聚合链[ZnL_2(TP)]_n(1),在这个配合物中通过链间的C-H…π相互作用形成了二维超分子层。1-苄基咪唑(L)和CuCl_2·2H_2O反应生成四核配合物[Cu_4(μ_4-O)Cl_6L_4](2),在这个配合物中通过C-H…Cl氢键形成了一维超分子链。测定了L,1和2的荧光发射光谱。     

调节悬臂式配体氮给体位置而诱导的单核及多核Keggin型化合物

通过调节苄基.1H-三氮唑配体中N给体位置,利用水热技术合成了5个新的Keggin型有机.无机杂化化合物:[Cu~Ⅱ(2-btz)_4(HPMo_(12)O_(40))]·(2-btz)·2H_2O(1)、[Cu~Ⅱ(2-btz)_4(HPW_(12)O_(40))]·(2-btz)·H_2O(2)、[Ag~Ⅰ_4(2-btz)_4(SiMo_(12)-O_(40))](3)、[Ag~Ⅰ_4(2-btz)_4(HPW~Ⅴ_2W~Ⅵ_(10)O_(40))](4)、[Cd~Ⅱ_3(3-btz)_8(H_2O)_4]·(HSiMo_(12)O_(40))_2·2H_2O(5)(2-btz=1-苄基-1H-(1,2,4)三氮,3-btz=1-苄基-1H-(1,3,4)三氮唑),并通过红外、元素分析和X-射线单晶衍射分析对5个化合物进行了表征.化合物1中多酸阴离子利用单核[Cu~Ⅱ(2-btz)_4]~(2+)亚单元共价交替连接形成一维直链结构;化合物2的多阴离子同样靠单核[Cu~Ⅱ(2-btz)_4]~(2+)亚单元交替连接,但形成的是"Z"字形链结构;化合物3与4同构,包含多阴离子作横栏的"梯子"型一维链结构,相邻一维链通过Ag-O键连接进一步形成三维框架结构.化合物1~4中的单核结构是由2-btz配体中分散的N给体诱导形成的.我们选用具有两个连续N给体的3-btz,获得了具有直线型三核镉簇的化合物5.通过调节同分异构配体中N给体位置,成功调控了多酸基单核及多核簇的形成.     

5-(3-吡啶基)-1H-四氮唑配体构筑的[Ni_2(ptzH)_3(H_2O)_6]~(4+)二聚体修饰的八钼酸盐化合物

在水热条件下采用5-(3-吡啶基)-1H-四氮唑配体合成了基于八钼酸盐的有机-无机杂化化合物[Ni_2(ptz H)_3(H_2O)_6](β-Mo_8O_(26))·2H_2O(ptz H=5-(3-吡啶基)-1H-四氮唑),并通过单晶X-射线、元素分析和红外光谱对其进行了表征.化合物中存在β型八钼酸盐[Mo_8O_(26)]~)4-_和阳离子二聚体[Ni_2(ptz H)_3(H_2O)_6]~(4+)2个孤立的亚单元.在这个二聚体中,2个Ni原子被3个ptz H分子固定.相邻的Ni二聚体之间存在丰富的π…π堆积作用,形成1个带有菱形格子的二维超分子金属-有机层.[β-Mo_8O_(26)]~(4-)多阴离子通过提供大量的氢键作用而占据在该超分子二维层的菱形格子中.     

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.     

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.     

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.     

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.