Hosts, cyclodextrin conjugated

Cyclodextrins Conjugated with Other Kinds of Hosts... 

It was found that formation of the 6-cyclodextrin inclusion complex improved the compound solubility from less than 0.5 mg/mL to 160 mg/mL, eliminating the formulation problems associated with solubility concerns [65]. Although retinoic acid does exhibit intrinsic CD when dissolved in dimethyl sulfoxide, the CD spectrum is drastically upon formation of the cyclodextrin inclusion complex (see Figure 10). That CD can be measured in the absorption bands located at 350 and 400 nm can be taken as evidence that it is the conjugated sidechain of the retinoic acid solute which becomes included in the cavity of the cyclodextrin host system. 

A number of examples of the use of host-guest chemistry in the creation of PET active systems have appeared. The reaction of P-cyclodextrin alcoholate with meso-tetrakis(pentafluorophenyl)porphyrin is reported to give a hydrophilic cyclodextrin-porphyrin conjugate in 14% yield. ° In the presence of guests such as 1,4-benzoquinone, anthraquinone-2-sufonate or 8-anilino-l-naphthalene sulfonic acid, PET operates as evidenced by the fluorescence... 

Cyclodextrins are the most used host compounds so far. Native cyclodextrins are effective inverse phase-transfer catalysts for the deoxygenation of allylic alcohols [3], epoxidation [4], oxidation [5], or hydrosilylation [6] of olefins, reduction of a,y9-unsaturated acids [7], a-keto ester [8], conjugated dienes [9] or aryl alkyl ketones [10]. Interestingly, chemically modified cyclodextrins like the partially O-methylated y0-cyclodextrin (RAME-y9-CD) show a better catalytic activity than native cyclodextrins in numerous reactions such as the Wacker oxidation [11], hydrogenation of... 

R. Fornasier, F. Marcuzzi, M. Parmagnani, U. Tonellato, Stereoselective reduction with sodium dithionite of conjugated enones in the presence of j8-cyclodextrin and its heptakis(2,6-di-0-methyl) derivative as host compounds or phase transfer agents, J. Inclusion Phenom. Mol. Recognit Chem., 1994, 18, 81-92. 

Harada and coworkers developed a variety of supramolecular polymers based on the host-guest interaction of cyclodextrin (CD) derivatives with hydrophobic guests, such as the adamantyl and cinnamoyl groups [45,46]. Consequently, various structures were obtained by conjugating cinnamoyl and hydrocinnamoyl groups to a- and/3-CD. When the hydrocinnamoyl group was attached to -CD, the flexibility of the linker resulted in the formation of a self-inclusion complex - in other words. 

Ikeda et al. and Konishi et al. reported on a supramolecular photocmrent generation system in combination with electrostatic and van der Waals interactions. In a Ceo-porphyrin bilayer prepared by electrostatic alternate adsorption (Fig. 27), the quantum yield of photocurrent generation is increased when self-aggregation of porphyrins is suppressed by host-guest interaction of cyclodextrin and porphyrin [104-106]. Cationic fullerene and tetracationic porphyrin bound on a DNA scaffold by electrostatic interactions was fabricated by conjugate polymer (Fig. 28). The quantum yield of photocurrent generation was 3.8% [107]. 

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