Preparation and guest binding of novel β-cyclodextrin dimers linked with various sulfur-containing linker moieties †

Yamamura, Hisao; Yamada, Shin‐ichi; Kohno, Keiko; Okuda, Nozomi; Araki, Shuki; Kobayashi, Kyoko; Katakai, Ryoichi; Kano, Kazuaki; Kawai, Maki

doi:10.1039/a905067a

Cited by 27 publications

(11 citation statements)

References 17 publications

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“…This reaction is postulated to be outersphere, by comparison with similar reactions in the literature. [41][42][43][44] The present study of these complexes will be inert to substitution, due to the non-availability of a co-ordination site for an inner-sphere precursor complexes. Our previous studies as well as literature reports 45 on similar types of complexes revealed only outer-sphere redox pathways.…”

Section: Electron-transfer Kineticsmentioning

confidence: 99%

Thermodynamics and kinetic investigation of electron transfer reactions of surfactant cobalt(iii) complexes containing diimine ligands with iron(ii) in the presence of liposome vesicles and amphiphilic salt media

2014

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Section: Electron-transfer Kineticsmentioning

confidence: 99%

Thermodynamics and kinetic investigation of electron transfer reactions of surfactant cobalt(iii) complexes containing diimine ligands with iron(ii) in the presence of liposome vesicles and amphiphilic salt media

2014

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“…In other work by this group, rigid bipyridyl spacers were also utilised ( Figure 6.26b). 148 Selenium-containing chains 149 have also been used, with -Se-(CH 2 ) 3 -Se-and 1,2-diselenobenzene units being used to bridge between two β-cyclodextrin units via the primary or in one case the secondary rims. In the case of the aliphatic spacers, the short two-carbon-chain spacer led to stronger complexation than the eight-carbon analogue, indicating that closeness of the cyclodextrins and/or lack of self-inclusion aids complexation.…”

Section: Bis and Multi-cyclodextrinsmentioning

confidence: 99%

Cyclodextrins

2011

Macrocycles

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Many of the compounds mentioned previously within this work are entirely synthetic in origin and as such do not occur naturally. The cyclodextrins are somewhat different however since they have a natural origin, being synthesised originally by bacterial fermentation and now via the use of enzymes from a natural feedstock. We have already discussed how small rings can be incorporated into macrocycles, such as in crown ethers and calixarenes. The cyclodextrins, also known as cycloamyloses, represent further examples of macrocyclic compounds formed by the joining of small rings to give rise to a much larger ring system. We intend to provide a general overview of cyclodextrin chemistry within this chapter; for further detail the reader is recommended to study some of the works listed in the Bibliography.Amylose is a water-soluble polysaccharide which is made up of 1,4-linked glucose units. Together with amylopectin it is one of the major constituents of starch. Cyclodextrins are made up of a series of α-D-glucopyranoside sugars linked together to form a macrocycle and can be thought of as cyclic versions of amylose. The three most common members of this group occur naturally; these are the hexamer (α-cyclodextrin), heptamer (β-cyclodextrin) and octamer (γ-cyclodextrin), as shown in Figure 6.1. The cyclic pentamer has been successfully synthesised in the laboratory -as have larger members of the series.Cyclodextrins were initially isolated by Villiers 1 as long ago as 1891; Villiers coined the name 'cellulosine' for these materials. He digested starch with Bacillus amylobacter to obtain amongst other things about 0.3% of a crystalline material. Elemental analysis showed it to be a polysugar and to have two distinct crystal forms. However, the techniques for in-depth separation and characterisation of these materials (thought to have been αand β-cyclodextrin) were not then available. Later work by Schardinger, 2 again using bacterial digestion of starch, managed to produce materials similar to cellulosine in yields of up to 30% and to separate and characterise the natural αand β-cyclodextrins, which were then named 'Schardinger sugars' or 'Schardinger dextrins'. The early history of these and the γ-cyclodextrins, the elucidation of their composition from glucose (they can also be thought of as consisting of maltose; for example, α-cyclodextrin can be thought of as consisting of six glucose or three maltose units) and their cyclic structure have all been reviewed. 3 In 1998, the journal Chemical Reviews published a special issue on cyclodextrins, to which the reader is referred in the Bibliography.Macrocycles: C onstruction, Chemistr y and Nanotechnology Applications, First Edition.Frank D avis and S éamus Higs on.

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“…[22][23][24] The cyclic structure forms a hydrophobic cavity and they can include a variety of guest molecules in their cavity. [25][26][27] The effects of cyclodextrin inclusion on the kinetics and mechanism of ligand substitution [28,29] and electron transfer reactions of transition metal complexes in aqueous solution [30,31] have received considerable attention in recent years.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of Reduction of Some Surfactant-Cobalt(III) Complexes by Iron(II)

Sasikala

Arunachalam

2010

Journal of Dispersion Science and Technology

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The electron transfer kinetics of the reaction between the surfactant-cobalt(III) complex ions, cis-[Co(en) 2 (C 12 H 25 NH 2 ) 2 ] 3þ , cis-a-[Co(trien)(C 12 H 25 NH 2 ) 2 ] 3þ (en:ethylenediamine, trien: triethylenetetramine, C 12 H 25 NH 2 : dodecylamine) by iron(II) in aqueous solution was studied at 298, 303, 308 K by spectrophotometry method under pseudo-first-order conditions using an excess of the reductant in self-micelles formed by the oxidant, cobalt(III) complex molecules, themselves. The rate constant of the electron transfer reaction depends on the initial concentration of the surfactant cobalt(III) complexes. DS # also varies with initial concentration of the surfactant cobalt(III) complexes. By assuming outer-sphere mechanism, the results have been explained based on the presence of aggregated structures containing cobalt(III) complexes at the surface of the self-micelles formed by the surfactant cobalt(III) complexes in the reaction medium. The rate constant of each complex increases with initial concentration of one of the reactants surfactant-cobalt(III) complex, which shows that self micelles formed by surfactantcobalt(III) complex itself has much influence on these reactions. The electron transfer reaction of the surfactant-cobalt(III) complexes was also carried out in a medium of various concentrations of b-cyclodextrin. b-cyclodextrin retarded the rate of the reaction.

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Preparation and guest binding of novel β-cyclodextrin dimers linked with various sulfur-containing linker moieties †

Cited by 27 publications

References 17 publications

Thermodynamics and kinetic investigation of electron transfer reactions of surfactant cobalt(iii) complexes containing diimine ligands with iron(ii) in the presence of liposome vesicles and amphiphilic salt media

Thermodynamics and kinetic investigation of electron transfer reactions of surfactant cobalt(iii) complexes containing diimine ligands with iron(ii) in the presence of liposome vesicles and amphiphilic salt media

Cyclodextrins

Kinetics of Reduction of Some Surfactant-Cobalt(III) Complexes by Iron(II)

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