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Topchieva, I. N.; Панова, И. Г.; Попова, Е. И.; Matukhina, E. V.; Gerasimov, V. I.

doi:10.1023/a:1011942319158

Cited by 4 publications

(3 citation statements)

References 5 publications

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“…Topchieva et al obtained a new kind of crystal hydrate for α-, β-, and γ-CDs (so-called form II) by removing the threading polymers from the initial polymer−CD IC crystals under the action of a selective organic solvent. , These products consist of extended cylindrical nanopores with diameters of ∼5, ∼7 and ∼10 Å for α-, β-, and γ-CD, respectively, which contained fewer water molecules and were thermally less stable compared to the crystal hydrates of the initial cyclodextrins (form I, cage structure) and the related polymer−CD ICs. Unfortunately, none of these cyclodextrins in columnar structure have been reported to be capable of reversible inclusion of polymers into the channels formed by the CD macrocycles.…”

Section: Introductionmentioning

confidence: 99%

Inclusion Compound Formation with a New Columnar Cyclodextrin Host

et al. 2002

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α- and γ-cyclodextrin in columnar structures with only water molecules included were successfully obtained by appropriate recrystallization from their aqueous solutions. These crystals were found to adopt a channel-type structure similar to the cyclodextrin inclusion compounds formed with guest polymers. Experimental investigations of their inclusion properties demonstrate that only α-cyclodextrin in the columnar structure (α-CDcs) is able to include both small molecules and polymers. Thermal measurements reveal that columnar structure α-CDcs contains three different types of water molecules. The most strongly held water molecules are located outside of the cyclodextrin cavity, likely hydrogen-bonded between the rims of neighboring cyclodextrins in the columnar α-CD stacks. X-ray analyses confirm that the channel structure is preserved in the dehydrated α-CDcs and its inclusion compounds formed with various guests. In contrast, a completely different behavior was observed for γ-CDcs in the columnar structure. It appears that α-CDcs, at least, can function as a nanoscopic filter for separating both small molecules and polymers on the basis of their abilities to be included, or not, in the narrow (∼0.5 nm) channels of the α-CDcs crystals.

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Section: Introductionmentioning

confidence: 99%

Inclusion Compound Formation with a New Columnar Cyclodextrin Host

et al. 2002

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“…Topchieva et al 19 first prepared a-CD in the columnar structure containing only water by first preparing a polymer-CD IC, then removing the polymer. Recently, Rusa et al 20 directly prepared a-CD in the columnar structure with only water as the guest molecule by rapid precipitation of a-CD from its aqueous solution using chloroform.…”

Section: Introductionmentioning

confidence: 99%

Structure and stability of columnar cyclomaltohexaose (α-cyclodextrin) hydrate

Hunt

Rusa

Tonelli

et al. 2004

Carbohydrate Research

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“…A channel-type structure is characteristic for long-chain molecule guest−CD ICs. The channel or columnar CD crystal structure, without included guests aside from water of hydration, can be readily obtained by an appropriate recrystallization process from a suitable solvent or by removing the included, threaded polymers from polymer−CD IC crystals under the action of a selective organic solvent. , Thus, the channel structure consisting of endless columns of stacked CD molecules connected to each other by hydrogen bonds has proved to be a stable structure even when there are no guest molecules included other than water.…”

Section: Introductionmentioning

confidence: 99%

Competitive Formation of Polymer−Cyclodextrin Inclusion Compounds

2003

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The hydrophobicity of the guest polymer and also the geometrical compatibility between guest polymer cross section and cavity diameter of the host cyclodextrin (CD) play important roles in the formation of inclusion compounds (ICs) between a mixture of one or two guest polymers with one or two different types of CDs, respectively. Specific polymer-CD interactions can be distinguished when, for example, polymer A-CD IC crystals are suspended in a solution containing polymer B, and a polymer B for polymer A exchange occurs, without CD-IC dissolution, during formation of polymer B-CD IC. When using the polymer pair poly( -caprolactone) (PCL)/poly(L-lactic acid) (PLLA), we have observed that PLLA-R-CD IC is completely converted to PCL-R-CD IC, while the reverse polymer transfer is almost completely prohibited. R-CD host molecules also preferentially included PCL chains from a common PCL/PLLA solution. In addition, observation of the transfer of PCL from PCL-γ-CD IC crystals suspended in a solution containing R-CD to form PCL-R-CD IC crystals now suspended in a solution containing γ-CD, while not observing the reverse transfer, has implications for the relative strength of polymer T polymer and polymer T CD interactions. Single and pairs of side-by-side parallel PCL chains occupy the channels of PCL-R-CD IC and PCL-γ-CD IC crystals, respectively, so our observations suggest that interactions between included PCL chains, which are only possible in PCL-γ-CD IC, do not lead to an increased stability for polymer-CD ICs.

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Cited by 4 publications

References 5 publications

Inclusion Compound Formation with a New Columnar Cyclodextrin Host

Inclusion Compound Formation with a New Columnar Cyclodextrin Host

Structure and stability of columnar cyclomaltohexaose (α-cyclodextrin) hydrate

Competitive Formation of Polymer−Cyclodextrin Inclusion Compounds

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