Cyclodextrins supramolecular assemblies

Braun T (1997) Water soluble fullerene-cyclodextrin supramolecular assembles. Preparation, structure, properties (an annotated bibliography). Full Sci Technol. 5 615-626. 

The importance of non - covalent interactions in biological systems has motivated much of the current interest in supramolecular assemblies [1]. A classical example of a supermolecule has been provided by the rotaxanes [2,3], in which a molecular rotor is threaded by a threaded by a linear axle . Another examples have been previously included as cyclic crown ethers threaded by polymers, paraquat -hydroquinone complexes [4] and cyclodextrin complexes [5,6],... 

New supramolecular assemblies based on a chitosan bearing pendant cyclodex-trins were prepared [23], In order to obtain these assemblies, adamantyl groups which can selectively be included in the cyclodextrins cavity were grafted on chitosan and several polyethylene glycol)s (PEG) with molecular weights of 3400,... 

The supramolecular assembly of (3-cyclodextrin-capped AuNPs on ITO previously coated with a monolayer of ferrocene molecules was shown to exhibit interesting redox properties, as presented in Figure 8.5.25 This is a fine example of the functionalization of a nanoparticle with a functionalized recognition element to create a unique supramolecular scaffold with tailor-made properties. Specifically, the electrocatalytic determination of ascorbic acid was demonstrated by this surface assembly with excellent discrimination over dopamine. 

Figure 8.5 Schematic illustration of a supramolecular assembly consisting of a ferrocene (FC) monolayer-modified ITO electrode functionalized with ff-cyclodextrin (p-CD)-cappcd AuNPs.25 (Reprinted with permission from F. Zuo et al., Electroanalysis 2008,20, 894-899. Copyright Wiley-VCH Verlag GmbH Co. KGaA.)...

Different cyclodextrin monolayers have been synthesized and their surface properties have been characterized. Kaifer et al. prepared per-6-thiol-cyclodextrins, and described the interfacial monovalent ferrocene complexation at the monolayer.55 Mittler-Neher et al. studied the kinetics of the adsorption of mono- and multithiolate-functionalized CD SAMs.56,57 Beulen et al.,58 Huskens et al.,59 Auletta et al.,60 and Nijhuis et al.61 reported on the concept of molecular printboards, that is, (3-cyclodextrin ((3-CD) SAMs on gold or silicon oxide substrates, onto which complementary multivalent guest-functionalized dendrimer molecules were adsorbed, resulting in the formation of kinetically stable supramolecular assemblies. With the... 

In inclusion complexation, a core is encapsulated by complexation (e.g., cyclodextrin). A supramolecular assembly is formed because of the noncovalent inclusion of an apolar core (e.g., oil) of suitable size within the hydrophobic cavity of the cyclodextrin. An example of inclusion complexation is the interaction between cyclodextrin and lycopene (Mele et al. 2002). The inclusion complex increases the water... 

Supramolecular chemistry typically involves the complexes based on molecular recognition, which include crown ethers, catenates, rotaxanes, etc. Azobenzene derivatives are often used as structural elements in such supramolecular assembly. Already in 1980 (Shinkai et ah, 1980), azobenzene moiety had been introduced into crown ether. Other recent examples include azobenzene-cyclodextrin complexes (Callari et ah, 2006), azobenzene-attached nanotube-cyclodextrin complexes (Descalzo et al., 2006), and molecular recognition complexes with DNA (Haruta et al., 2008). Numerous examples of photoswitch-able azobenzene supramolecular systems in solutions can be found (Yagai et al., 2005 Balzani et al., 2002). But there are no investigations in these systems concerning photoorientation and mass transport. 

Whereas the majority of dendrimer-based lipophilic-hydrophilic inclusion phenomena discussed thus far results in random guest positioning on a branched framework, ordered interactions in supramolecular assemblies are also of interest. For example, Gonzalez et al. reported the surface modification of poIy(propyl-eneimine)s with cobaltocenium groups that are easily reduced to Co(0). Reaction of the amine termini with I-chlorooarbonylcobaltocenium afforded the metal-terminated dendrimers. The lipophilic, charge-neutral poly-cobaltocenes were rendered H2O soluble via addition of /1-cyclodextrin (36, fi-CD) based on its cylindrical... 

Tan S, Ladewig K, Fu Q, Blencowe A, Qiao GG (2014) Cyclodextrin-based supramolecular assemblies and hydrogels recent advances and future perspectives. Macromol Rapid Commun 35 1166-1184... 

Auzely-Velty R, Rinaudo M (2002) New supramolecular assemblies of a cyclodextrin-grafted chitosan through specific complexation. Macromolecules 35 7955-7962. doi 10.1021/ma020664o... 

Cyclodextrin inclusion compounds are examples of a well-studied class of supramolecular assemblies that have found applications as functional materials. Most of the reported BCD inclusions adopt a channel packing motif which can... 

A wide range of cyclodextrin-based supramolecular assemblies are now available,and in particular, the attachment of cationic polymers such as polyethylenimine has facilitated transport across cell membranes, permitting tar-getted delivery of both siRNA and DNA. ... 

Several examples of supramolecular assemblies involving synthetic macromolecules have been described as MRI contrast agents. An important approach is to exploit hydrophobic interactions between the cavity of cyclodextrins (CDs), mainly /S-CDs, and suitably functionalized Gd " " complexes. It has been recognized early on that the application of ohgomers or polymers of CDs containing several CD units represents further advantages with respect to... 

A suspension obtained from the water-solnble anionic mew-tetrakis(4-carboxyphenyl)porphyrin and MWCNTs was nsed as an optical probe for DNA detection [242]. The same target was achieved very recently, constructing a supramolecular assembly with the water-soluble anionic 5-(4-aminophenyl)-10,15,20-tris(4-sulfonatophenyl)porphyrin, covalently linked to MWCNTs and complexed with cyclodextrins (CD, either a-CD or P-CD) [243]. 

Ning J, Wang Y, Wu Q, Zhang X, Lin X, Zhao H. Novel supramolecular assemblies of repulsive DNA-anionic porphyrin complexes based on covalently modified multi-walled carbon nanotubes and cyclodextrins. RSC Adv 2015 5 21153-60. 

Macrocyclic compounds act as main players in the field of supramolecular chemistry because they form organized supramolecular assemblies by cavity-size dependent host-guest interactions. Therefore, development of the field of supramolecular chemistry has been pushed by the discovery of four key macrocycles, the cyclodextrins, crown ethers, calix[n]arenes and cucurbit[n]urils. In 2008, we introduced a new class of macrocycles Pillar[n]arenes . On account of their novel cross section of properties and great potential, pillar[n]arenes are becoming dominant in the field of macrocyclic chemistry and are opening up a new supramolecular chemistry, which cannot be achieved by the other four key players. The field called pillar[ ]arene chemistry was started in 2008, and there was a small handful of players in the beginning. Fortunately, many chemists have joined the field of pillar[n]arene chemistry since 2012 and, now, pillar[n]arene chemistry attracts the attention of numerous researchers. 

In conclusion, ILs can act as guests to form supermolecules with several kinds of host molecules (i.e., cyclodextrins, cucurbit[n]urils and calixarenes), and can participate the constructing of supramolecular assemblies (i.e., micelles, microemulsions, lyotropic LCs, vesicles and gels). Besides, ILs can affect the formation of supramolecular structures, for example, the formation of polyrotaxanes and polypseudorotaxanes, the formation of the supramolecular structures in the extraction systems based on crown ethers, and so on It is... 

The main supramolecular self-assembled species involved in analytical chemistry are micelles (direct and reversed), microemulsions (oil/water and water/oil), liposomes, and vesicles, Langmuir-Blodgett films composed of diphilic surfactant molecules or ions. They can form in aqueous, nonaqueous liquid media and on the surface. The other species involved in supramolecular analytical chemistry are molecules-receptors such as calixarenes, cyclodextrins, cyclophanes, cyclopeptides, crown ethers etc. Furthermore, new supramolecular host-guest systems arise due to analytical reaction or process. 

This paper is not a review covering the entire field of carbohydrate-recognition in any organized system. Many excellent papers have already been devoted to supramolecular systems such as cyclodextrins, podands, coronands or cryptants able to entrap carbohydrate molecules [1]. This article only deals with the molecular recognition of mono and oligosaccharides in organized self-assemblies of amphiphilic carbohydrates (possibly blended with other lipids) in aqueous medium i.e. in assemblies mimicking the cell membrane. 

Electrostatic self-assembly was combined with supramolecular chemistry to obtain inclusion complexes of a polymeric nonlinear optical (NLO) active dye and modified [3-cyclodextrin with induced chromophore orientation [37], The polyanion is a N,N-diallyl-aniline and sodium-2-acrylamido-2-methylpropanesulfonate copolymer functionalized with pendant azo group. The modified /i-cyclodextrin oligo-cation was obtained by treatment of hcptakis(6-dco y-6-iodo-/i-cyclodcxtrin) with excess pyridine. A linear polyamine, chitosan, was also combined with the polyanion, for comparison. Films were deposited on glass slides by dipping them alternatively in aqueous solutions of the cation and the polyanion. UV-visible spectra indicate dye aggregation and suggest the formation of an inclusion complex of the dye with the cyclodextrin, thus isolating the chromophores. 

Summary The analysis of supramolecular structures containing polymers, and the discussion about the effect of polymeric materials with different chemical structures that form inclusion complexes is extensively studied. The effect of the inclusion complexes at the air-water interface is discussed in terms on the nature of the interaction. The entropic or enthalpic nature of the interaction is analyzed. The description of these inclusion complexes with different cyclodextrines with several polymers is an interesting way to understand some non-covalent interaction in these systems. The discussion about the generation and effect of supramolecular structures on molecular assembly and auto-organization processes is also presented in a single form. The use of block copolymers and dendronized polymers at interfaces is a new aspect to be taken into account from both basic and technological interest. The effect of the chemical structure on the self-assembled systems is discussed. 

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