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1.
Yoshinori Takashima Akira Harada 《Journal of inclusion phenomena and macrocyclic chemistry》2017,87(3-4):313-330
Molecular recognition is essential for realizing functional supramolecular materials. Non-covalent host–guest interactions are an effective tool to introduce switching and functional properties into materials. This review focuses on the achievement of selective molecular adhesion, self-healing, toughness, and actuation properties. These functions have been achieved by reversible bond formation with cyclodextrins (CDs). Self-healing materials with host–guest interactions involving CDs have been used to achieve redox-responsive healing properties and healing efficiency. Furthermore, the materials, which undergo self-healing by chemical and physical mechanisms, exhibit rapid and efficient self-healing properties under semi-dry conditions. To prepare a supramolecular actuator using host–guest complexes, two approaches have been introduced. The first is the functionalization of a supramolecular gel actuator by changing the cross-linking density, and the second is the functionalization of a topological gel actuator by changing distances between the cross-linking points. Both actuators exhibit contractive bending behavior. This review summarizes advancements within the past ten years in supramolecular materials that function via the chemical mechanism of host–guest interactions and the physical mechanism of the sliding motion of ring molecules. 相似文献
2.
Yoshinori Takashima Akira Harada 《Journal of inclusion phenomena and macrocyclic chemistry》2017,88(3-4):85-104
Molecular recognition is essential for realizing functional supramolecular materials. Non-covalent host–guest interactions are an effective tool to introduce switching and functional properties into materials. This review focuses on the achievement of selective molecular adhesion, self-healing, toughness, and actuation properties. These functions have been achieved by reversible bond formation with cyclodextrins (CDs). Self-healing materials with host–guest interactions involving CDs have been used to achieve redox-responsive healing properties and healing efficiency. Furthermore, the materials, which undergo self-healing by chemical and physical mechanisms, exhibit rapid and efficient self-healing properties under semi-dry conditions. To prepare a supramolecular actuator using host–guest complexes, two approaches have been introduced. The first is the functionalization of a supramolecular gel actuator by changing the cross-linking density, and the second is the functionalization of a topological gel actuator by changing distances between the cross-linking points. Both actuators exhibit contractive bending behavior. This review summarizes advancements within the past 10 years in supramolecular materials that function via the chemical mechanism of host–guest interactions and the physical mechanism of the sliding motion of ring molecules. 相似文献
3.
Jose M. Garcia Fernandez Carmen Ortiz Mellet Jacques Defaye 《Journal of inclusion phenomena and macrocyclic chemistry》2006,56(1-2):149-159
Cyclodextrins (CDs) represent a unique example of complementarity between nanotechnology and biotechnology. Their molecular nanocavity character and the possibility of selective functionalization offer an excellent opportunity for chemical elaboration of unique nanostructures in a three-dimensional network. Several approaches from our laboratories, aimed at endowing CDs with biorecognition properties by incorporation of saccharide ligands, are discussed. Applications range from site-specific drug delivery systems to more fundamental studies on carbohydrate–protein interactions. Results on the de novo synthesis of a new family of glyconanocavities constructed from α,α-trehalose building blocks, namely cyclotrehalans (CTs), and on their complexing properties are also presented. 相似文献
4.
荧光碳点探针是近几年来发展起来的一种新型荧光探针,具有传统有机染料、荧光染色蛋白及一般荧光纳米材料无法比拟的独特优势,如具有良好的水溶性、化学惰性、低毒性、易于功能化、抗光漂白性、可调谐和生物相容性等优异性能,因而引起研究者的广泛关注。目前已发展水热法等近十种较为经济便捷的方法,可进行大规模的荧光碳点制备,在细胞功能研究及细胞表面和内部功能分子的探测、组织的成像、病菌的定位等方面得到了较为广泛的应用。笔者对近年来荧光碳点的合成方法、依赖于碳点尺寸和波长等性质的发光性能,以及荧光碳点在生物成像等方面的应用作一简要综述,并对其在药用植物病理方面的应用提出展望,期望为丰富荧光碳点在生物成像领域的应用提供一定的借鉴和参考。 相似文献
5.
I. N. Topchieva I. G. Panova V. V. Spiridonov E. V. Matukhina B. I. Kurganov 《Moscow University Chemistry Bulletin》2010,65(5):320-325
Noncovalent columnar polymers (NCPs) based on cyclodextrins (CD) are polymeric assemblies of molecules that have continuous
hollow channels, the width of which is determined by the diameter of the cavity of the initial CDs. The repeating fragment
in an NCP is the CD molecule. For NCPs that were obtained by the exclusion of polymer backbone macromolecule from the corresponding
inclusion complexes (ICs) based on β-cyclodextrin (NCPexcl), the polymer length, expressed as the number of macrocycles in a single chain (n) is determined by the size of the included ligand, polypropylene glycol (PPG), and is the PPG polymerization degree divided
by two. The determination of the molecular weight of an NCP obtained by the precipitation method (NCPprec) is rather difficult, since they are present in the aggregated state rather than in the form of individual molecules in solution.
To estimate the molecular weight of NCPprec, an indirect method is used, which is based on the determination of the aggregation rate of the ICs formed as a result of
the interaction between an NCP and polypropylene glycol with a fixed molecular weight (MW), in this case PPG 1000. The comparison
of the aggregation rates of the inclusion between NCPexcb (which were synthesized using PPGs with different molecular weights) and PPG 1000 with the aggregation rate of the inclusion
complex on the basis of NCPprec provided the estimation for the MWs of single polymer chains. The fact that the samples of NCPprec contain ∼30% of the monomeric
β-CD was taken into account when constructing the calibration curve. It was demonstrated that the MW of the polypropylene
glycol corresponding to NCPprec is 1320 Da. Consequently, ∼11–12 molecules of β-CD are included in the single chains of NCPprec. 相似文献
6.
Chun Li Naoe Isshiki Hiromu Saito Kenichi Ogata Akinori Toyota 《Journal of Polymer Science.Polymer Physics》2009,47(2):130-137
The β‐cyclodextrin (β‐CD) and γ‐cyclodextrin (γ‐CD) inclusion compounds (ICs) with two different molecular weight isotactic polypropylene (iPP) were prepared. The ICs with high molecular weight iPP as guest molecule had lower inclusion rate. The crystallization behavior of iPP blended with the CDs and ICs was investigated by differential scanning calorimetry, polarized optical microscopy, and light scattering. The iPP blended with the ICs was found to exhibit higher crystallization temperature (TC), smaller spherulites, and faster crystallization rate than those of neat iPP. These results indicate that the ICs play a role of nucleating agent on the crystallization of iPP and induce the accelerated crystallization. Both β‐CD‐iPP ICs and γ‐CD‐iPP ICs with longer iPP molecular chains had better nucleation effect than the ICs with shorter iPP molecular chains. This suggested that the nucleation effect of these ICs was affected by the inclusion rate of ICs. The lower inclusion rate could result in better nucleation effect, due to the interaction of extended iPP molecules inside the CD cavity and iPP molecules in the matrix. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 130–137, 2009 相似文献
7.
Michael T. Huggins Adrianne K. Tipton Qingqi Chen David A. Lightner 《Monatshefte für Chemie / Chemical Monthly》2000,75(2):825-838
The synthesis, crystal structure determination, conformational analysis, and spectroscopic properties of 3,3′-diethyl-4,4′-dimethyl-2,2′-dipyrryl ketone (1) are reported. The dipyrryl ketone is a model for the dipyrrole core of 10-oxobilirubin, a presumed metabolite in alternate pathways of excretion of the yellow pigment of jaundice, bilirubin. In the crystal, 1 adopts a helical conformation, with a molecule of one helicity being hydrogen-bonded to two molecules of the opposite helicity. Thus, 1 self-assembles via hydrogen bonding into supramolecular double-stranded arrays, where molecules of the same helicity comprise one strand and are paired through hydrogen bonding to molecules of opposite helicity in the second strand. In the observed molecular conformation each pyrrole ring and adjacent carbonyl group are rotated into an sc conformation (torsion angle ∼29 °), with each N-H pointing in the same direction as the C*O. Molecular mechanics/dynamics calculations predict the sc,sc conformation, absent hydrogen bonding, to be the most stable, but only by a few tenths of a kj/mol. In CHCl3, 1 is monomeric according to vapor pressure osmometry studies (). 1H NMR NH chemical shifts in CDCl3 suggest a predominantly anti orientation of the C=O and pyrrole NHs, which is opposite to the orientation observed in the crystal. 相似文献
8.
Michael T. Huggins Adrianne K. Tipton Qingqi Chen David A. Lightner 《Monatshefte für Chemie / Chemical Monthly》2000,131(8):825-838
Summary. The synthesis, crystal structure determination, conformational analysis, and spectroscopic properties of 3,3′-diethyl-4,4′-dimethyl-2,2′-dipyrryl
ketone (1) are reported. The dipyrryl ketone is a model for the dipyrrole core of 10-oxobilirubin, a presumed metabolite in alternate
pathways of excretion of the yellow pigment of jaundice, bilirubin. In the crystal, 1 adopts a helical conformation, with a molecule of one helicity being hydrogen-bonded to two molecules of the opposite helicity.
Thus, 1 self-assembles via hydrogen bonding into supramolecular double-stranded arrays, where molecules of the same helicity comprise one strand and
are paired through hydrogen bonding to molecules of opposite helicity in the second strand. In the observed molecular conformation
each pyrrole ring and adjacent carbonyl group are rotated into an sc conformation (torsion angle ∼29 °), with each N-H pointing in the same direction as the C*O. Molecular mechanics/dynamics
calculations predict the sc,sc conformation, absent hydrogen bonding, to be the most stable, but only by a few tenths of a kj/mol. In CHCl3, 1 is monomeric according to vapor pressure osmometry studies (). 1H NMR NH chemical shifts in CDCl3 suggest a predominantly anti orientation of the C=O and pyrrole NHs, which is opposite to the orientation observed in the crystal.
Received February 4, 2000. Accepted February 14, 2000 相似文献
9.
An inclusion complex (1) has been prepared by β-cyclodextrin with α-aminopyridine. The result of X-ray crystallographic analyses showed that the
α-aminopyridine molecules in the β-cyclodextrin cavities possess two opposite orientations, i.e. the amine group of α-aminopyridine
pointing to the primary side (1a, occupancy: 41.2%) or the secondary side (1b, occupancy: 58.8%) of β-cyclodextrin, forming two scalelike supramolecular aggregations. The studies of 2D NMR and circular
dichroism spectra indicated that the α-aminopyridine molecule is deeply embedded in the β-cyclodextrin cavity to form host-guest
inclusion complex, showing a circular dichroism spectrum induced by the chiral cavity of cyclodextrin. The results obtained
are helpful for understanding the molecular recognition and aggregation mechanism between the host and guest. 相似文献
10.
Chun Li Naoe Isshiki Hiromu Saito Kazufumi Kohno Akinori Toyota 《Journal of Polymer Science.Polymer Physics》2010,48(4):389-395
The β‐cyclodextrin (β‐CD) and γ‐cyclodextrin (γ‐CD) inclusion complexes (ICs) with four kinds of polyolefin were prepared. The crystallization behavior of isotactic poly(1‐butene) (iPB‐1) blended with these CDs and ICs was investigated by differential scanning calorimetry, polarized optical microscopy, and wide‐angle X‐ray diffraction. The iPB‐1 blended with the ICs was found to exhibit higher crystallization temperature (TC), smaller spherulites, and faster crystallization rate than neat iPB‐1. These results indicate that the ICs can act as nucleating agent on the crystallization of iPB‐1 and induce the accelerated crystallization. The guest molecules of ICs play an important role in the nucleation effect of ICs on the crystallization of iPB‐1. ICs with polyolefin having higher TC as guest molecules have higher nucleation effect than the one with polyolefin having lower TC as guest molecules. And, the CDs and ICs induce different crystal form of iPB‐1. The crystal of iPB‐1 blended with CDs is defective, whereas the crystal of iPB‐1 blended with ICs is more perfect. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 389–395, 2010 相似文献
11.
氨基甲酸酯型脱氧胆酸分子钳对中性分子的识别性能研究 总被引:3,自引:0,他引:3
利用差紫外光谱法考察了新型分子钳1~6对苯胺、对硝基苯胺、对甲氧基苯胺等中性分子的识别性能, 测定了25 ℃下, 在CHCl3中主客体间的结合常数(Ka)和自由能变化(ΔG0). 结果表明, 所有分子钳主体对所考察的客体分子显示良好的识别作用, 主客体间形成1∶1型主客体络合物. 识别作用的主要推动力为多重氢键和π-π重叠等的作用. 讨论了主客体间形状、大小匹配和几何互补及识别模式等因素对识别能力的影响, 并利用核磁共振氢谱与计算机模拟作为辅助手段对实验结果进行了解释. 相似文献
12.
R.G. Woolley 《Journal of mathematical chemistry》1998,23(1-2):3-12
The paper surveys how chemistry has developed over the past two centuries starting from Lavoisier’s classification of the
chemical elements at the end of the eighteenth century; the subsequent development of the atomic–molecular model of matter
preoccupied chemists throughout the nineteenth century, while the results of the application of quantum theory to the molecular
model has been the story of this century. Whereas physical chemistry originated in the nineteenth century with the measurement
of the physical properties of groups of chemical compounds that chemists identified as families, the goal of chemical physics
is the explanation of the facts of chemistry in terms of the principles and theories of physics. Chemical physics as such
was only possible after the discovery of the quantum theory in the 1920’s. By then the first of the sub‐atomic particles had
been discovered and seemingly it is no longer possible to discuss chemical facts purely in terms of atoms and molecules –
one has to recognize the electron and the nucleus, the parts of atoms. The combination of classical molecular structure with
the quantum properties of the electron has given us a tremendously successful account of chemistry called ‘quantum chemistry’.
Yet from the perspective of the quantum theory the deepest part of chemistry, the existence of chemical isomers and the very
idea of molecular structure that rationalizes it, remains a central problem for chemical physics.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
13.
14.
Summary Four cyclodextrin derivatives (CDs) were synthesized by substituting 3-OH of 2,6-di-O-pentyl-β-cyclodextrin with four different
chain lengths of acyl groups (butyryl, valeryl, heptanoyl, octanoyl). The chromatographic properties of the four CD derivatives
as stationary phases of capillary gas chromatography (CGC) were investigated. These CDs exhibit a wide range of application.
Not only five pairs of enantiomers of pyrethroic acid methyl esters were separated on the four CDs, but also some other racemic
compounds. Among the four CDs, 2,6-di-O-pentyl-3-O-butyryl-β-CD possesses better enantiomer separation abilities to the studied
enantiomers of pyrethroic acid methyl esters than the other studied CDs. The extension of chain length of the acyl groups
in 3-position of CDs cannot improve the enantiomer separation abilities of the CD derivatives. 相似文献
15.
Prof. Dr. Mohamed E. El‐Khouly Prof. Dr. Shunichi Fukuzumi Prof. Dr. Francis D'Souza 《Chemphyschem》2014,15(1):30-47
Various molecular and supramolecular systems have been synthesized and characterized recently to mimic the functions of photosynthesis, in which solar energy conversion is achieved. Artificial photosynthesis consists of light‐harvesting and charge‐separation processes together with catalytic units of water oxidation and reduction. Among the organic molecules, derivatives of BF2‐chelated dipyrromethene (BODIPY), “porphyrin’s little sister”, have been widely used in constructing these artificial photosynthetic models due to their unique properties. In these photosynthetic models, BODIPYs act as not only excellent antenna molecules, but also as electron‐donor and ‐acceptor molecules in both the covalently linked molecular and supramolecular systems formed by axial coordination, hydrogen bonding, or crown ether complexation. The relationships between the structures and photochemical reactivities of these novel molecular and supramolecular systems are discussed in relation to the efficiency of charge separation and charge recombination. Femto‐ and nanosecond transient absorption and photoelectrochemical techniques have been employed in these studies to give clear evidence for the occurrence of energy‐ and electron‐transfer reactions and to determine their rates and efficiencies. 相似文献
16.
Roberto Cao Alex Fragoso Eduardo Almirall Reynaldo Villalonga 《Supramolecular chemistry》2013,25(3):161-170
Cyclodextrins (CDs) are a class of cyclic oligosaccharides composed of α(1→4)-linked D-glucopyranose units in the 4 C 1 chair conformation. The overall form of the molecules is a truncated cone with an essentially hydrophobic cavity. Such a structure allows them to form stable inclusion complexes with a wide variety of guests. That is the reason for which CDs constitute an indivisible part of supramolecular chemistry, a field of chemistry in constant growth and development all around the world. Here we present a survey of the different types of supramolecular compound that CDs and their derivatives can form and the applications we are targeting in Cuba. This consists mainly of the following. ? Pharmaceutical formulations of copper(II) complexes insoluble in water, solubilized by their inclusion in βCD and in one of its dimers. ? Cu,Zn-SOD enzyme mimetics based on copper(II) complexes of CD derivatives with ammonium salts included in the CD cavity. ? Enzymes conjugated, by both chemical and enzymatic methods, to CDs with increased thermostability and catalytic activity. ? Sensors based on the self-assembly of CD derivatives on metal electrodes and nanoparticles, which permit selective differentiation between species with very similar electrochemical properties. 相似文献
17.
18.
Abstract
Four complexes of 3,3-diphenylpropanoate (L) and 4,4′-bipyridine as auxiliary bridging ligands were synthesized and characterized, namely [Zn(L)2(4bpy)(EtOH)2]∞ (1), [Co(L)2(4bpy)(EtOH)2]∞ (2), [Ni(L)2(4bpy)(EtOH)2]∞ (3), and [Cu(L)2(4bpy)(H2O)]∞ (4) (4bpy = 4,4′-bipyridine). X-ray single-crystal diffraction analyses show that complexes 1–4 all take one-dimensional (1D) fishbone-like structures incorporating bridging 4bpy ligands. The complexes show different supramolecular frameworks interlinked via intermolecular hydrogen bonds, π···π stacking, and/or C–H···π supramolecular interactions. Complex 3 only has a simple one-dimensional fishbone-like chain, whereas complexes 1 and 2 show two-dimensional supramolecular structures by interchain C–H···O hydrogen bonds. Complex 4 is assembled into two-dimensional layers and then an overall three-dimensional framework by a combination of interchain O–H···O hydrogen bonds and C–H···π supramolecular interactions. The luminescent properties of the ligands and their complexes were investigated. 相似文献19.
20.
《Colloids and surfaces. A, Physicochemical and engineering aspects》2007,292(1):51-55
The polypseudorotaxanes (PPRs) have been prepared by supramolecular self-assembly of β-cyclodextrins (β-CDs) threaded onto the triblock copolymers (Pluronic F127) in an ionic liquid [1-n-butyl-3-methylimidazolium hexafluorophosphate (bmimPF6)] with two different manners. Structural characterizations of the assembled PPRs are carried out in detail respectively with XRD, 13C CP/MAS NMR, 1H NMR and DSC techniques. The results obtained indicate a channel-type crystalline structure for such produced inclusion complexes (ICs). Which one will finally be included inside β-CD, F127 or bmimPF6, is related to the ethanol amount around the initially β-CD/bmimPF6 ICs. At higher ethanol concentration, F127 may squeeze bmimPF6 molecules out from β-CD and thread themselves instead into the cavity of β-CD and finally precipitate with more CDs being stacked. 相似文献