Polymer inclusion complexes

Hydrogels formed by PEO block copolymers have previously been proposed as sustained release matrix [85,86], The a-CD-PEO hydrogel delivery system differs in that the gelation relies on the formation of a polymer inclusion complex induced by the PEO-threaded CDs. The properties of the supramolecular hydrogel can be fine-tuned with the composition, molecular weight and chemical structure of the polymer or copolymers. 

Kadokawa J, Kaneko Y, Tagaya H, Chiba K (2001b) S5mthesis of an amylose-polymer inclusion complex by enzymatic polymerization of glucose 1-phosphate catalyzed by phosphorylase enzyme in the presence of polyTHF a new method for synthesis of polymer-polymer inclusion complexes. Chem Commun 449-450... 

The molecular size of 1 is smaller than that of 2, therefore 1 easier enters the p-CD cavity than 2, and easier is released from the inclusion complex. Therefore the 1/p-CD polymer complex can deactivate bacteria faster than 2/p-CD polymer complex. The association constant of the 1/ P-CD polymer inclusion complex is higher than in the case of 2, because 1 has smaller size than 2. It should be pointed out that very high antimicrobial activities of antibiotics/p-CD polymer complexes enable their use in various fields, including production of cellulose materials with antimicrobial properties. 

Polymer chains are isolated from their neighbors when they are included in narrow inclusion channels. The formation of a polymer inclusion complex provides an opportunity to study the conformation and mobility of isolated polymer chains. These studies have been carried out using nuclear magnetic resonance, differential scanning calorimetry (DSC), and electron spin resonance ([ H]-NMR, [ C]-NMR, DSC, and ESR) spectroscopies. 

For example, the same dimer complex which contains two molar equivalents of ethanol, underwent photoreaction to give a higher molecular weight polymer (M = 12 000). The formation of such inclusion complexes with the solvent is rather generally observed with similar types of dimers formed with alcohols and some other solvents and, consequently, this enhances photopolymerizability. Such complex formation with a solvent may be one of the promising techniques that can be used for diolehn compounds in order to obtain polymers with high molecular weights. 

The inability of y-CD to complex with POx under the same conditions as for / -CD indicates the failure of POx to meet the prerequisite for inclusion complex formation that the polymer chain fits well into the CD cavity and is hydrophobic enough to stabilize the complex. 

The polymerization of trans-1,3-pentadiene, 149, in a chiral channel inclusion complex with enantiomerically pure perhydrotriphenylene affords an optically active polymer, 150 (236). Asymmetric polymerization of this monomer guest occurs also in deoxycholic acid inclusion complexes (237). 

Research Focus Method of preparing viscoelastic polymers using crosslinked polyrotaxane inclusion complexes consisting of polyethylene glycol (PEG)-carboxyhc acid and a-cyclodextrin. 

The aqueous solubility of CD also enables their potential application as poly-rotaxane-based drug carriers. Yui and coworkers incorporated CD onto PEO chains in polypseudorotaxanes and polyrotaxanes [92-94], The releasing kinetics of CD from the polymer chain were studied. The release was governed by the inclusion complexation equilibrium. Biodegradation to cleave the BG units was shown to cause the release of the CD from the polyrotaxanes. 

Ammar, H. O., Salama, H. A., Ghorab, M., and Mahmoud, A. A. 2006. Implication of inclusion complexation of glimepiride in cyclodextrin-polymer systems on its dissolution, stability and therapeutic ef cacy. Int. J. Pharm. 320 53-57. 

Cycloocta-2,4-dien-l-one (95) exists as an equilibrium mixture of the conformers 95a and 95b in solution, and conversion between these two enantiomeric forms is too fast to allow their isolation at room temperature. Photoreaction of 95 in pentane for 1 hr gives racemic 96 in 10% yield along with polymers. When a solution of (—)-ll and 95 was kept at room temperature for 12 h, a 3 2 inclusion complex of (—)-ll with 95a was obtained as colorless needles. Irradiation of the 3 2 complex of (—)-ll with 95a for 48 hr gave (—)-96 of 78% ee in 55% yield. X-ray crystal structure analysis is given in Ref. 51. 

Inclusion properties of molecular nanotubes composed of crosslinked a-cyclodextrin was investigated [47], Induced circular dichroism was used to probe the formation and dissociation of complexes between the nanotubes and azobenzene modified polyethylene glycol), either with or without a hydrophobic alkyl chain. The inclusion complex between the nanotubes and polymers formed at room temperature, and the polymers dissociated from the nanotubes with increasing temperature. 

Optically active vinyl sulfoxide was prepared by a combination of resolution and elimination reaction. Firstly, inclusion complexation of rac-2-chloroethyl m-tolyl- sulfoxide (118) and 14b in benzene gave, after two recrystallizations from benzene, a 1 1 complex of 14b and (+)-118 of 100% ee in 72% yield. Secondly, treatment of the complex with 10% NaOH gave optically pure (+)-m-tolyl vinyl sulfoxide (119) by HC1 elimination as colorless oil. Rapid polymerization of the (+)-119 proceeded by treatment with BuLi or BuMgBr at -78 °C to give optically active polymer (120). Oxidation of 120 with H2O2 gave optically active polysulfone (121).48... 

All-trans-perhydrotriphenylene (PHTP) (cf. insert in Figure 14) is the product of exhaustive hydrogenation of triphenylene. It belongs to one of ten stereoisomers of PHTP. The chiral compound of high rotational symmetry (D3 — C3 -h 3 C2) forms inclusion complexes. The stereoselective polymerization via 7-radiation of the prochiral diolelin 1,3-pentadiene within the chiral nano channels of (.R)-(-)-all-trans-PHTP led to an optically active 1,4-trans-isotactic polymer (Nattaand Farina, 1976) (cf. Figure 13). 

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. 

Potential use of complexes of y - CD with organic compounds, including polymers, was also reviewed by Szejtli [6, 12, 13], y - CD are able to incorporate metal ions as ligands to prepare magnetic nano - particles [7,14], Harada and Ka-machi [8,15] first found that poly (ethylene oxide) (PEO) thread a- CD rings to form polymer - cyclodextrin complex. Since their finding of inclusion complex formation of polymer chains with a- CD, a large number of studies on inclusion complexes of... 

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