Cyclodextrin inclusion complexe

Figure 5-9. Free energy reaction coordinate diagram for System 2 of Table 4-3, the formation of a cyclodextrin inclusion complex.

Binding Forces Contributing to the Formation of Cyclodextrin Inclusion Complexes... 

Several intermolecular interactions have been proposed and discussed as being responsible for the formation of cyclodextrin inclusion complexes in an aqueous solution 6-10). They are... 

It is well known that spontaneous resolution of a racemate may occur upon crystallization if a chiral molecule crystallizes as a conglomerate. With regard to sulphoxides, this phenomenon was observed for the first time in the case of methyl p-tolyl sulphoxide269. The optical rotation of a partially resolved sulphoxide (via /J-cyclodextrin inclusion complexes) was found to increase from [a]589 = + 11.5° (e.e. 8.1%) to [a]589 = +100.8 (e.e. 71.5%) after four fractional crystallizations from light petroleum ether. Later on, few optically active ketosulphoxides of low optical purity were converted into the pure enantiomers by fractional crystallization from ethyl ether-hexane270. This resolution by crystallization was also successful for racemic benzyl p-tolyl sulphoxide and t-butyl phenyl sulphoxide271. 

These interesting results are attributed to the formation of an alkene/ cyclodextrin inclusion complex as well as the solubility of the chemically modified cyclodextrin in both phases. Prior to this study, hydroformylation in the presence of unmodified cyclodextrins had been studied by Jackson, but the results were rather disappointing.174... 

Eto, S., Noda, H., Noda, A. (1994). Simultaneous determination of antiepileptic dmgs and their metabolites, including chiral compounds, via 3-cyclodextrin inclusion complexes by a switching chromatographic technique. J. Chromatogr. B 658, 385-390. 

Panja S, Chakravorti S (2002) Photophysics of 4-(N, N-dimethylamino)cinnamaldehyde/ alpha-cyclodextrin inclusion complex. Spectrochim Acta A Mol Biomol Spectrosc 58(1) 113-122... 

Lopez-Nicolas JM, Bru R, Sanchez-Ferrer A and Garcia-Carmona F. 1995. Use of soluble lipids for biochemical processes linoleic acid cyclodextrin inclusion complexes in aqueous solutions. Biochem J 308 151-154. 

Complexes of metal cations with carbohydrates in solution, 47, 1 -43 Courtois, Jean Emile, obituary of, 49,11 -18 Cyclomalto-oligosaccharides(cyclodextrins), inclusion complexes of, 46, 205-249 addendum to, 46, 333-335... 

Matsuzawa Y, Tamura SI, Matsuzawa N, Ata M (1994) Light stability of a P-cyclodextrin inclusion complex of a cyanine dye. J Chem Soc Faraday Trans 90 3517-3520... 

Even less expected, perhaps, are the reactions involving gas-solid addition of HBr, Cl2, and Br2 to a, 3-unsaturated acid guest species in a- and P-cyclodextrin inclusion complexes (242). Although the chemical yields are not high, the optical yields in some cases are extraordinary. Thus, chlorine addition to methacrylic acid in a-cyclodextrin yields (- )-2,3-dichloro-2-methylpropanoic acid in nearly quantitative optical yield. The 3-cyclodextrin methacrylic acid clathrate undergoes chlorine addition to yield preferentially the enantiomeric (+ )-product, with an e.e. of 80%. 

Braun T, Buvari-Barcza A, Barcza L, Konkoly-Thege I, Fodor M, Migali B (1994) Mechanochemistry a novel approach to the synthesis of fullerene compounds. Water soluble Buckminster fullerene - gamma- cyclodextrin inclusion complexes via solid-solid reaction. Solid State Chem. 74 47-51. 

Ventura CA, Giannone I, Musumeci T, Pignatello R, Ragni L, Landolfi C, Milanese C, Paolino D, Puglisi G (2006) Physico-chemical characterization of disoxaril-dimethyl-beta-cyclodextrin inclusion complex and in vitro permeation studies. Eur J Med Chem 41 233-240. 

An attempt to directly resolve alkyl alkanesulfmates via 0-cyclodextrin inclusion complexes was only partly successful (35,106). In the majority of cases, the optical purity of the isolated esters was in the 5 to 10% range. In the case of isopropyl methanesulfinate, however, inclusion was highly stereospecific and afforded the ester with 68% optical purity. 

The stereospecific conversion of sulfinates into sulfoxides of known chirality has been applied as a general method for determining the absolute configuration of a wide range of optically active sulfinic esters. For example, the absolute configurations of a series of alkyl alkanesulfinates obtained by asymmetric synthesis (107) or resolution via 3-cyclodextrin inclusion complexes (106) were determined by this method. 

Methyl-P-cyclodextrin Inclusion complexes with Blocks clathrin also 16,42,46,47 s. 

The majority of reported studies of formation of cyclodextrin inclusion complexes in solution have been mainly concerned with determination of the stability constants by using equilibrium spectroscopic techniques, and the measurement of the enthalpy and entropy changes characterizing the complexation reaction. The aim of much of this work has been to determine the driving force of complex-formation. Despite the amount of research in this area, however, no general agreement has been reached, and... 

Fig. 4.—Enthalpy-Entropy Compensation for Alpha Cyclodextrin Inclusion-Complexes. [The guest identification numbers are as given in Table II.]...

---