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1.
《中国化学快报》2023,34(7):108040
The binding interactions between 4-aminopyridine (4-AP) and a series of cucurbit[n]urils (Q[5], Q[6], TMeQ[6], Q[7], Q[8]) have been studied using 1H NMR spectroscopy, UV–vis absorption spectroscopy, isothermal titration calorimetry (ITC) and X-ray crystallography. The data indicates that the Q[5]@4-AP complex exhibits exo binding, which is not observed in the other four host-guest complexes. Furthermore, X-ray crystallography clearly reveals how the Q[n]s bind with 4-AP to form complexes, for example Q[5] forms an outer-surface complex, whilst Q[6], TMeQ[6] and Q[7] formed 1:1 host and guest type complexes, and Q[8] formed a stable 1:2 ternary complex due to its large cavity, which can accommodate two 4-AP molecules. 相似文献
2.
Background Pillar[n]arene(PA[n])contains a symmetrical structures,where para-bridge connection between the units looks like a column-like or pillar shape and polygonal structure from side and top views,respectively.The attached groups to the PA[n]are pointing towards the opposite directions along the columnar axis. 相似文献
3.
ZHOU Hui DU Shao-Wu 《结构化学》2007,26(6):711-716
The self-assembly reactions of MIICl2 (M = Ni, Co) with the flexible bix ligand [bix = 1,4-bis(imidazole-1-ylmethyl)benzene] yielded a 2D network [NiII(bix)2Cl2]n 1 and a 1D chain [CoII(bix)Cl2]n 2. Their crystal structures have been determined by X-ray single-crystal diffraction analysis. Complex 1 characters a two-dimensional grid-type structure and crystallizes in monoclinic, space group P21/c with a = 7.7231(7), b = 12.7787(9), c = 13.9374(13) , β = 105.419(4)o, C28H28Cl2N8Ni, Mr = 606.19, Ζ = 2, V = 1326.0(2) 3, Dc = 1.518 g/cm3, μ = 0.969 mm-1, F(000) = 628, R = 0.0429 and wR = 0.0783 for 2503 observed reflections (I > 2σ(I)). Compound 2 is a one-dimensional chain and crystallizes in orthorhombic, space group Pbca with a = 11.3696(6), b = 10.2128(6), c = 14.4943(9) , C14H14Cl2CoN4, Mr = 368.12, Z = 4, V = 1683.01(17) 3, Dc = 1.453 g/cm3, μ = 1.334 mm-1, F(000) = 748, R = 0.0317 and wR = 0.0800 for 1778 observed reflections (I > 2σ(I)). Magnetic properties of the title complexes were also investigated. 相似文献
4.
One linear template 13 and one cyclophane template 15, both incorporating two electron rich 1,4-dialkoxybenzene units and one diamide unit, have been synthesized. By utilizing donor-acceptor interaction and/or intermolecular hydrogen bonding assembling principles, one novel hetero[3]rotaxane 22·4Cl, possessing one neutral and one tetracationic ring components, has been synthesized from 13, through neutral [2]rotaxane 21 as intermediate. With 15 as template, tetracationic [2]catenane 23·4PF6 was assembled by using donor-acceptor interaction, but no neutral [2]rotaxane could be obtained under the typical conditions of hydrogen bonding assembling principle. The interlocked supramolecular compounds have been characterized and their spectral properties are investigated. 相似文献
5.
Recent developments in the synthesis and applications of the cucurbit[n]uril family of synthetic hosts has led to an increasing interest in the detailed studies of their interactions with a wide variety of guests. This paper describes a quantitative study of the effects of the number and placement of positive charges on the binding of viologen guests to cucurbit[7]uril and cucurbit[8]uril. A series of viologen derivatives with one to four charges was characterised by isothermal titration calorimetry, 1H NMR spectroscopy and mass spectrometry to determine the stoichiometry, affinity and mode of binding. These data show that stoichiometry can be controlled by the placement of charge, and that affinity can be increased by the addition of positive charges. This study should serve as a guide for the design of supramolecular structures built from viologens and cucurbit[n]urils. 相似文献
6.
One linear template 13 and one cyclophane template 15, both incorporating two electron rich 1,4‐dialkoxybenzene units and one diamide unit, have been synthesized. By utilizing donor‐acceptor interaction and/or intermolecular hydrogen bonding assembling principles, one novel hetero[3]rotazane 22·4Cl, possessing one neutral and one tetracationic ring components, has been synthesized from 13, through neutral [2]rotaxane 21 as intermediate. With 15 as template, tetracationic [2]catenane 23·4PF6 was assembled by using donor‐acceptor interaction, but no neutral [2]rotaxane could be obtained under the typical conditions of hydrogen bonding assembling principle. The interlocked supramolecular compounds have been characterized and their spectral properties are investigated. 相似文献
7.
Russian Journal of Organic Chemistry - New spiro heterocycles, spiro[benzo[h]chromene-4,3′-indoles] and spiro[benzo[f]chromene-1,3′-indoles], have been synthesized in 50–60% yield... 相似文献
8.
9.
Fa Fu YANG Xia ZHAO Cui Yu HUANG Hong Yu GUO Si Ning ZHENG Qi PENG 《中国化学快报》2006,17(8):1029-1032
Biscalixarenes, as examples of higher order molecular architectures than normal calixarene derivatives, were studied extensively in the recent years due to they possess two calixarene cavities which have the potential for complexing with two guests in two… 相似文献
10.
MA Peihua DONG Jun XIANG Shuangchun XUE Saifeng ZHU Qianjiang TAO Zhu ZHANG Jianxin & ZHOU Xin . Institute of Applied Chemistry Guizhou University Guiyang China . The Key Laboratory of Chemistry for Natural Products of Guizhou Province Guiyang China 《中国科学B辑(英文版)》2004,47(4)
Since the structure of cucurbituril(Q[6]) has been determined in 1981[1] and its homologues cucurbit [n = 5,7,8 and 10]uril(Q[5], Q[7], Q[8] and Q[10]) have been reported in 2000[2,3], 2002[4], a series of host-guest complexes[5—7], novel supramolecular as-semblies[8—10], molecular encapsulates[11,12] and mo-lecular containers[13,14] based on Q[n] have been stud-ied extensively. All cucurbituril homologues have common char-acteristic features, i.e. hydrophobic cavity, and polar carbonyl gr… 相似文献
11.
M Alonso P Geerlings F de Proft 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(35):10916-10928
Recently, hexaphyrins have emerged as a promising class of π-conjugated molecules that display a range of interesting electronic, optical, and conformational properties, including the formation of stable M?bius aromatic systems. Besides the M?bius topology, hexaphyrins can adopt a variety of conformations with Hückel and twisted Hückel topologies, which can be interconverted under certain conditions. To determine the optimum conditions for viable M?bius topologies, the conformational preferences of [26]- and [28]hexaphyrins and the dynamic interconversion between the M?bius and Hückel topologies were investigated by density functional calculations. In the absence of meso?substituents, [26]hexaphyrin prefers a planar dumbbell conformation, strongly aromatic and relatively strain free. The M?bius topology is highly improbable: the most stable tautomer is 33?kcal?mol(-1) higher in energy than the global minimum. On the other hand, the M?bius conformer of [28]hexaphyrin is only 6.5?kcal?mol(-1) higher in energy than the most stable dumbbell conformation. This marked difference is due to aromatic stabilization in the M?bius 4n electron macrocycle as opposed to antiaromatic destabilization in the 4n+2 electron system, as revealed by several energetic, magnetic, structural, and reactivity indices of aromaticity. For [28]hexaphyrins, the computed activation barrier for interconversion between the M?bius aromatic and Hückel antiaromatic conformers ranges from 7.2 to 10.2?kcal?mol(-1) , in very good agreement with the available experimental data. The conformation of the hexaphyrin macrocycle is strongly dependent on oxidation state and solvent, and this feature creates a promising platform for the development of molecular switches. 相似文献
12.
1 INTRODUCTION Polymeric manganese complexes with fascinating topological chemistry have received considerable interest[1, 2]. The complexation of phen with man- ganese ion gives rise to a wide variety of coordi- nation complexes; however, (phen)Mn coordina- tion polymers are rare since the chelation of phen results in 1 to 3 5-membered chelating rings, ob- structing the way towards the coordination poly- mer. Similar situation has also been observed for 2,2?-bipyridine (bpy) which has si… 相似文献
13.
p-Perfluoroalkylealix[4]arenes were prepared readily from the reaction of calix-[4]arene with perfluoroalkyl iodides in the presence of sodium dithionite or sodium hydroxy-methanesulfinate under mild conditions,These fluorine-containing calixarenes showed bettersolubilities in common organic solvents as compared to their nonperfluoroalkylation analogand formed inclusion complexes with many neutral molecules as well as fluorocarbons. 相似文献
14.
Quan-Zheng Zhang Can-Zhong Lu Wen-Bin Yang Chuan-De Wu Ya-Qin Yu Ying Yan Jiu-Hui Liu Xiang He 《Journal of Cluster Science》2003,14(3):381-390
Two Keggin-type heteropolyanions were synthesized and characterized by X-ray crystal structure and elemental analysis as well as infrared spectroscopy. Both K3[VMo12O40]19H2O (1) and [N
i
(H2O)6][H3PMoVMoVI
11O40]230 H2O (2) were prepared in aqueous solution. Compound 1 crystallized in the space group Pm-3m, a=10.6513(1) Å, V=1208.4(3) Å3, Z=1. Compound 2 crystallized in the space group R-3 with a=b=13.9669(2) Å, c=42.0075(5) Å, V=7096.71(2) Å3, Z=3. The compound 1 contains a {K6VMo12O40} group in which six potassium ions form a regular {K6} octahedron. The heteropolyanion [VMo12O40]3– was capped by six potassium ions and enclosed by {K6} octahedron. A three-dimensional structure was formed by the buildup of {K3[VMo12O40]}
n
. Compound 2 contains a one-electron reduced heteropolyanion [H3PMoVMoVI
11O40]1–. Ni2+ coordinated by six water molecules as the counter cation balances the negative charge of the molecule. 相似文献
15.
《Tetrahedron letters》2019,60(45):151215
Synthesizing novel electron-rich calix[n]arene derivatives to alter the electronic properties of calixarene-based materials has been one of the long-standing interests. Herein, two new electron-rich calix[n]arenes (n = 4 and 8) with different sizes were synthesized by acid-catalyzed condensation reaction of 1,3,5-tripropoxybenzene and paraformaldehyde. Both derivatives were fully characterized with 1H and 13C NMR, mass spectrometry and X-ray crystallography. Furthermore, their electrochemical properties and oxidized product (cation radicals) have also been investigated. 相似文献
16.
[n.n.n]Propellanes and bicyclo[n.n.n]alkanes (1=n=3) in which the bridgeheads and bridges are composed of different Group 14 elements will not be ideal homologues of the all-carbon propellanes and bicycloalkanes. We used quantum-chemical calculations to conclude which of these could possibly be stable at ambient temperature. Structures, strain, and dimerization energies of [n.n.n]propellanes and bicyclo[n.n.n]alkanes with C-based tethers and with Si, Ge, or Sn at the bridgehead positions were calculated. The aptitude to add water was probed in selected cases. Comparisons were made with the analogous all-C propellanes and bicycloalkanes. All heavy 1,(n+2)-dimetallabicyclo[n.n.n]alkanes should be thermally stable and suitable synthetic targets, even though the moisture sensitivity of 1,3-dimetallabicyclo[1.1.1]pentanes increases as Group 14 is descended. For 1,(n+2)-dimetalla[n.n.n]propellanes, the incompatibility between the tether and M--M bond lengths impacts strongly on structure and stability. At ambient temperature 1,3-disila[1.1.1]propellanes should oligomerize instantly upon formation, whereas 1,3-digerma- and 1,3-distanna[1.1.1]propellanes should be less prone to oligomerize and possibly isolable. The 1,4-dimetalla[2.2.2]propellanes with M=Si-Sn have biradical ground states and can presumably only be observed under inert conditions at cryogenic temperatures. Finally, we predict that 1,5-disila[3.3.3]propellane will be persistent at ambient temperature, but 1,5-distanna[3.3.3]propellane should rapidly oligomerize. 相似文献
17.
Synthesis and Crystal Structure of [La(BTC)(H2O)6]n 总被引:1,自引:0,他引:1
WEN Yi-Hanga b c CHENG Jian-Kaia FENG Yun-Longb ZHANG Jiana c LI Zhao-Jia YAO Yuan-Gena② a 《结构化学》2005,24(12):1440-1444
1 INTRODUCTION desired topologies owing to their rich coordination modes[8~12] and we have been exploring the chemi- The assembly of metal-organic infinite frame- stry of coordination polymers constructed by tran- works via coordination of metal ions with multifunc- sition metals and benzoic multicarboxylic acids[13~16]. tional organic ligands is a field of increasing inte- In addition, lanthanide ions have high affinity for rest[1~4]. A rational designed and predictable coor- hard donor a… 相似文献
18.
Novel macrocyclic anion receptors based on the principle of anion-π interactions were reported. By means of both post-macrocyclization modification protocol and the stepwise fragment coupling approach, functionalized oxacalix[2]arene[2]triazines bearing two other electron-deficient (hetero)aromatic rings on the lower rim were efficiently synthesized. The resulting oxacalix[2]arene[2]triazine macrocyclesadopt 1,3-alternate conformation, yielding therefore an expanded electron-deficient cavity or space consisting of two triazine rings and two appending aromatic rings. Spectroscopic titration study showed the selective interaction of the pentafluorophenyl-substituted oxacalix[2]arene[2]triazine with azide and fluoride in solution with the binding constants (K(1:1)) ranging from 1.33 × 10(3) to 3.52 × 10(3) M(-1). 相似文献
19.
We reported the first syntheses of 2- and 3-(2-(benzo[b]selenophen-2-yl)-indoles and their Diels–Alder reactions to furnish six unique annulated benzoselenphene carbazoles. This facile route can be used to synthesize selenium-containing biindolyl derivatives that possessed potential pharmaceutical activities. 相似文献
20.
《中国化学快报》2017,(2)
A green,convenient,high yielding and one-pot procedure for the synthesis of novel spiro[benzo[α]pyrano[2,3-c]phenazine]derivatives by domino multi-component condensation reaction between 2-hydroxynaphthalene-l,4-dione,benzene-l,2-diamines,ninhydrine,and malononitrile in the presence of a catalytic amount of 1,3-dimethyl-7H-purine-2,6-dione(theophylline) as an expedient,eco-friendly and reusable solid base catalyst under thermal,microwave irradiation and solvent-free conditions.This procedure has also been applied successfully for the synthesis of benzo[α]pyrano[2,3-c]phenazines. 相似文献