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191.
A rigid supramolecular polymer was constructed in aqueous solution via cucurbit[8]uril(CB[8]) host recognition with a rigid monomer containing an azobenzene unit and two 4,4'-bipyridin-1-ium(BP)moieties in the two ends, which also exhibited photo-responsiveness owing to the photoinduced trans–cis isomerization of azobenzene group. 相似文献
192.
《Arabian Journal of Chemistry》2020,13(3):4824-4834
A new partially substituted calix[4] pyrrole derivative obtained by the introduction of three thioamide functionalities in the N-rim has been synthesised and fully characterised by 1H, 13C, HSQC, ROESY NMR and mass spectroscopy. Computer modelling suggested an alternate conformation which was confirmed through ROESY 1H NMR. The receptor interacts only with the silver cation as shown by 1H NMR. The strength of interaction is quantitatively assessed by titration calorimetry. N-rim modification eliminates the possibility of interaction with anions. Unlike calix[4] pyrrole derivatives obtained by the introduction of functionalities through the meso-position, addition of Hg(NO3)2 leads to the degeneration of the receptor as demonstrated by 1H NMR, FTIR and XPS analyses. This is for the first time reported. Molecular simulation studies show significant strain in the mercury bound ligand in bonds, angles, torsions leading to the destruction of the receptor. Given the negative environmental impact produced by the availability of silver ions in aquatic organisms, the fundamental studies indicate that this receptor offers potential applications for monitoring silver (ion selective electrode) or indeed as a decontaminating material for removing silver ions from water. 相似文献
193.
Francesca Deganello Avesh Kumar Tyagi 《Progress in Crystal Growth and Characterization of Materials》2018,64(2):23-61
Solution combustion synthesis (SCS) is a worldwide used methodology for the preparation of inorganic ceramic and composite materials with controlled properties for a wide number of applications, from catalysis to photocatalysis and electrocatalysis, from heavy metal removal to sensoristics and electronics. The high versatility and efficiency of this technique have led to the introduction of many variants, which allowed important optimization to the prepared materials. Moreover, its ecofriendly nature encouraged further studies about the use of sustainable precursors for the preparation of nanomaterials for energy and environment, according to the concept of circular economy. On the other hand, the large variety of expressions to define SCS and the often-contradictory definitions of the SCS parameters witnessed a scarce consciousness of the potentiality of this methodology. In this review article, the most important findings about SCS and the selection criteria for its main parameters are critically reviewed, in order to give useful guidelines to those scientists who want to use this methodology for preparing materials with improved or new functional properties. This review aims as well (i) to bring more clarity in the SCS terminology (ii) to increase the awareness of the SCS as a convenient tool for the synthesis of materials and (iii) to propose a new perspective in the SCS, with special attention to the use of ecofriendly procedures. Part of the review is also dedicated to precautions and limitations of this powerful methodology. 相似文献
194.
Proton transfer from a difunctional pillar[5]arene containing two carboxylic acid moieties to amine-based guests occurs in the host–guest complexation. The binding affinities are enhanced effectively due to the existence of electrostatic interactions. 相似文献
195.
Rose Mary Michell Iwona Blaszczyk‐Lezak Carmen Mijangos Alejandro J. Müller 《Journal of Polymer Science.Polymer Physics》2014,52(18):1179-1194
In this article, a review of recent literature on confined crystallization within nanoporous anodic aluminum oxide (AAO) templates is presented. For almost all infiltrated polymeric materials, crystal orientation within the nanopores is a function of pore diameter. Tc and Tm usually decrease and are a function of pore size. When no pore interconnection remains, the crystallization occur at large supercoolings in heterogeneity free environments. Hence, the nucleation mechanism changes from heterogeneous to surface or homogeneous nucleation. The crystallization kinetics of infiltrated polymers should be close to first order, since in confined environments nucleation is the determining step of the overall crystallization and Avrami indexes (n) of ~1 (or lower in some cases) should be obtained. Examples are provided where these conditions have been met and first order kinetics (n = 1) were measured as opposed to higher orders (n = 3?4) for the same polymer in the bulk. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 1179–1194 相似文献
196.
A luminescent and injectable supramolecular hydrogel was successfully constructed through the non-covalent cross-linking of polymers mediated by tetraphenylethylene-bridged cyclodextrin oligomers, presenting the strong blue fluorescence, the reversible gelation behavior responsive to various external stimuli and the good mechanical property of shear thinning. 相似文献
197.
Bingbing Shi Zhengtao Li Yuezhou Liu Liqing Shangguan Huangtianzhi Zhu Huaqiang Ju Feihe Huang 《Tetrahedron letters》2018,59(38):3477-3480
Here we report the design and syntheses of two new triptycene-based rigid acyclic C-shaped hosts, clip[5]arenes C[5]OH and C[5]ME, and the strong host–guest complexation between C[5]OH and an electron-poor bipyridinium salt, paraquat G. The Ka value for the host–guest complex C[5]OH???G was calculated to be (1.09?±?0.36)??×??105?M?1 in acetone by using a non-linear curve-fitting method based on the UV–vis absorption titration experiments. Furthermore, based on this new host–guest recognition motif, a novel pseudopolyrotaxane-like supramolecular structure was constructed with C[5]OH threaded on polyviologen polymer VP-10. 相似文献
198.
Changkun Xia Yuanyuan Min Wen Sun Kai Yang Yunlong Wu 《Journal of Coordination Chemistry》2018,71(1):12-21
Two dinuclear Fe(III) metal–organic complexes with tetracarboxylate and chelating N-donor ligands, [Fe(Hbtec)(phen)(H2O)]2·2H2O (1) and [Fe(Hbtec)(bpy)(H2O)]2·2H2O (2) (H4btec = 1,2,3,5-benzenetetracarboxylic acid, phen = 1,10-phenanthroline, bpy = 2,2′-bipyridine) have been prepared and characterized by elemental analysis, IR spectroscopic, and X-ray diffraction methods. Both complexes crystallize in the monoclinic space group P21/c with two Fe(III) ions bridged by two Hbtec3? ligands into a dinuclear unit. Hydrogen bonding connects the dinuclear units into a 3-D framework. The dinuclear units are 10-connected nodes that produce a 3-D framework with topology Schläfli symbol as (312·428·55). Thermal stabilities and luminescent properties of the two complexes have also been investigated. 相似文献
199.
《无机化学与普通化学杂志》2018,644(2):82-85
Using ferrocenecarboxylic acid (FcCOOH) as organometallic ligand in the synthesis of heterometallic complexes led to the isolation of the compound [(FcCOO)Cu(bpy)2](BF4) · bpy · CH3OH. It was characterized by IR spectroscopy, EA, powder XRD, UV, and TGA measurements. Single‐crystal X‐ray structural analysis revealed that a unique 2D supramolecular network purely formed by aromatic π ··· π stacking interactions was observed, namely, {[(FcCOO)Cu(bpy)2](BF4) · bpy · CH3OH}∞ ( 1 ). The solid UV/Vis diffuse reflectance spectrum revealed the optical energy gap of 1 to be 3.54 eV, which is dramatically blue shifted compared with the value of ferrocene. Experimental results of thermal analysis and electrochemical analysis show that 1 has good thermal and better electrochemical stability. 相似文献
200.
《无机化学与普通化学杂志》2018,644(18):1084-1090
Reaction of a imidazole phenol ligand 4‐(imidazlo‐1‐yl)phenol (L) with 3d metal salts afforded four complexes, namely, [Ni(L)6] · (NO3)2 ( 1 ), [Cu(L)4(H2O)] · (NO3)2 · (H2O)5 ( 2 ), [Zn(L)4(H2O)] · (NO3)2 · (H2O) ( 3 ), and [Ag2(L)4] · SO4 ( 4 ). All complexes are composed of monomeric units with diverse coordination arrangements and corresponding anions. All the hydroxyl groups of monomeric cations are used as hydrogen‐bond donors to form O–H ··· O hydrogen bonds. However, the coordination habit of different metal ions produces various supramolecular structures. The NiII atom shows octahedral arrangement in 1 , featuring a 3D twofold inclined interpenetrated network through O–H ··· O hydrogen bond and π–π stacking interaction. The CuII atom of 2 displays square pyramidal environment. The O–H ··· O hydrogen bond from the [Cu(L)4(H2O)]2+ cation and lattice water molecule as well as π–π stacking produce one‐dimensional open channels. NO3– ions and lattice water molecules are located in the channels. 3 is a 3D supramolecular network, in which ZnII has a trigonal bipyramid arrangement. Two different rings intertwined with each other are observed. The AgI in 4 has linear and triangular coordination arrangements. The mononuclear units are assembled into a 1D chain by hydrogen bonding interaction from coordination units and SO42– anions. 相似文献