Project Research Center for Fundamental Sciences, Graduate School of Science, Osaka University Harada Group
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Preparation of Supramolecular Complexes with Cyclodextrin

About Cyclodextrin (CD) Supramolecular Catalyst Using Modified Cyclodextrin
Preparation of Supramolecular Complexes with Modified Cyclodextrin Single-Molecular Imaging of Rotaxane Based on Glass Substrates : Observations of Rotary Movement of a Rotor
Structure Control of Supramolecular Complexes by External Stimulus-Responsive Molecular Recognition of CD for Polymer chains
Preparation of Supramolecular Complexes with p-Conjugated Molecules CD Crystal Structure Gallery

Preparation of Supramolecular Complexes with Modified Cyclodextrin

Poly[2]rotaxane

Poly[2]rotaxane and supramolecular assembly have been prepared by modified cyclodextrins bearing an adamantyl group in an aqueous medium.

 

広い口側の二級水酸基にゲスト分子が修飾されたCDによるポリ[2]ロタキサン合成
Proposed supramolecular structures formed by cinnamamide a-CD bearing an adamantyl group

Atsuhisa Miyawaki, Masahiko Miyauchi, Yoshinori Takashima, Hiroyasu Yamaguchi and Akira Harada "Formation of supramolecular isomers; poly[2]rotaxane and supramolecular assembly"
Chem. Commun., 2008,(4), 456 - 458,

 

Herical Supramolecular Polymer

a-CD with a 3-p-tert-Boc-cinnammoylamino group forms a supramolecular polymer. The existence of substitution/substitution interactions among the adjacent monomers of supramolecular polymer has been proved by the observation of positive and negative Cotton bands in the circular dichroism spectra. The supramolecular polymer was found to form a left handed helical conformation. The formation of helical supramolecular polymer with some cooperativity is shown by the CD spectra.

修飾CDにより形成されたらせん超分子ポリマー
A proposed structure of a supramolecular polymer formed by 3-p-tBocCiNH-a-CD in aqueous solution.

Miyauchi, M.; Takashima, Y.; Yamaguchi, H.; Harada, A.
"Chiral Supramolecular Polymers Formed by Host-Guest Interactions"
J. Am. Chem. Soc. 2005, 127(9), 2984-2989.

Supramolecular Oligomers with Alternating a- and b-Cyclodetrin Units

6-p-tert-BocCiNH-b-CD formed intramolecular complexes. When adamantane carboxylic acid is added in the solution of 6-p-tert-BocCiNH-b-CD, the adamantane group is included in the b-CD cavity and the cinnamoyl group is kicked out of the cavity. When adamantane carboxylic acid was attached to a-CD at the 3-position (3-AdHexNH-a-CD) and the 3-AdHexNH-a-CD was mixed with 6-p-tert-BocCiNH-b-CD in D2O in a one-to-one ratio, they formed a heterodimer, which lines up end-to-end in longitudinal rows to form supramolecular oligomers in alternating manner.

 

図14.-CDと-CDが交互に並んだ超分子ポリマー

Miyauchi, M.; Harada, A.
"Construction of Supramolecular Polymers with Alternating a-, b-Cyclodextrin Units Using Conformational Change Induced by Competitive Guests"
J. Am. Chem. Soc. 2004, 126(37), 11418-11419.

[2]Rotaxane Oligomer

First, p-aminohydrocinnamoyl b-CD was prepared. This compound forms an intramolecular complex with cinnamoyl group being inside its own cavity, When adamantane carboxylic acid (AdCax) was added to this aqueous solution, AdCax was included in an b-CD cavity in place of the amino-cinnamoyl group. The aminocinnamoyl group was released from the b-CD cavity to be exposed in water. When a-CD was added to the solution, cinnamoyl group was found to be included into a-CD to give a pseudo-[2]rotaxane. Then another stopper group (TNB) was attached to the aminocinnamoyl group. The [2]rotaxane with a host(b-CD) and a guest (TNB) has been obtained.41 Although the [2]rotaxane exists as a monomer in organic solvents(DMSO), the rotaxane formed supramolecular [2]rotaxane polymers in water as proved by 1H-NMR spectra (Fig.15). The linear supramolecular polymers were observed by AFM techniques.

 

[2]ロタキサンを構成単位とする超分子ポリマー([2]ロタキサンポリマー)
Proposed structures of supramolecular oligomer incorporating
3-AdHexNH-a-CD and 6-p-tBocCiNH-b-CD.

Miyauchi, M.; Hoshino, T.; Yamaguchi, H.; Kamitori, S.; Harada, A.
"A [2]Rotaxane Capped by a Cyclodextrin and a Guest: Formation of Supramolecular [2]Rotaxane Polymer"
J. Am. Chem. Soc. 2005, 127(7), 2034-2035.

 

Cyclic Daisy Chain

Cyclic tri[2]rotaxanes (daisy chain necklace) containing cyclodextrins have been obtained by closing a tri[2]rotaxane containing a-CD and 6-(4-aminocinnamate) with 2,4,6-trinitrobenzene sulfonic acid sodium salt. If the molecule changes its conformation (or co-conformation), the ring may expand or shrink by external conditions (temperature, solvents, photochemically, electrochemically). These compounds are important because the cycle can be used as a chemical valve as can be seen in ion channels in biological membranes.


Daisy chain necklace: cyclic tri[2]rotaxane containing a-CD

Hoshino, T.; Miyauchi, M.; Kawaguchi, Y.; Yamaguchi, H.; Harada, A.
"Daisy Chain Necklace: Tri[2]rotaxane Containing Cyclodextrins. "
J. Am. Chem. Soc., 2000 , 122(40), 9876-9877.

Supramolecular Polymer incorporating CD Dimer

CD-based supramolecular polymers have been prepared using a b-CD dimer and ditopic guest dimers having adamantyl groups.692,693 The ditopic guest dimers with varying flexibility and adamantyl moieties were prepared to investigate the conformation of the supramolecular cpmplexes. The ROESY spectra of the b-CD dimer with the ditopic adamantane guest dimers showed NOE between the protons of adamantyl substituents and the inner protons of CD. The b-CD dimer forms supramolecular polymers with stiff guest molecules to give high molecular weight supramolecular polymers, and the b-CD dimer gives cyclic supramolecular oligomers with flexible ditopic guest dimers. A 1:1 mixture of the b-CD-PEG dimer and the adamantane-PEG dime forms of the self-organized intermolecular supramolecular polymers.

 


Proposed structures of supramolecular oligomer incorporating b-CD dimer and adamanane dimer.

Ohga, K.; Takashima, Y.; Takahashi, H.; Kawaguchi, Y.; Yamaguchi, H.; Harada, A.
"Preparation of Supramolecular Polymers from a Cyclodextrin Dimer and Ditopic Guest Molecules: Control of Structure by Linker Flexibility"
Macromolecules 2005, 38 (14), 5897-5904.

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