Properties of clathrochelates

Ion association or ion-pairing reactions are most commonly studied for clathrochelate complexes exhibiting unique inertness. These reactions attract particular interest due to their marked effect on the kinetics and direction of the redox and photochemical reactions and on the characteristics of electrochemical processes. In certain cases, ion association reactions govern the catalytic activity of compounds. The ion-pairing ability of clathrochelates is utilized to resolve racemates into optical isomers (enantiomers) and to separate optically active anions using clathrochelates as chiral eluents. 

Most studies deal with cobalt clathrochelates. In several cases, nonmacrocyclic tris-diamine complexes have also been investigated to elucidate the specificity of interactions brought about by the formation of cage structures. 

Hydrogen bonding between coordinated amino groups and CIO4 anions in the crystal of nickel(II) sarcophaginate was determined by X-ray crystallography (Fig. 34) [176]. 

It was established that there is a correlation between the association constants for the [Co(sep)]3+...Har ion pairs and the basicity of halogenide anions (Fig. 35), which indirectly confirmed the coordination via hydrogen bonds in solution [301]. Association constants for the [Co(sep)]3+...F , Cr, r, CIO4 , and C20i ion pairs were calculated fi-om 

A detailed study of ionic associates of the [CoCsep)] cation with S203 and S04 anions was reported in Ref. 304. The formation of the associates with one and two anionic species was detected hy UV-vis spectrophotometry, optical CD, and solubility measurements. For the ion pair with 8203 ion, the first- and second-stage association constants were found to be =2.5x102 and 

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Finally, the practical applications of the unique properties of clathrochelates and perspectives on the synthesis of new clathrochelates are described in Chapters 6 and 7, respectively. 

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