rac- and Lambda-tris(ethylenediamine)cobalt(III) cyclotriphosphate dihydrate with the chemical formulas rac-[Co(en)(3)]P(3)O(9).2H(2)O (1) and Lambda-[Co(en)(3)]P(3)O(9).2H(2)O (2) were synthesized, and their crystal structures were determined by single-crystal X-ray analyses. In 1, the cationic complex molecule [Co(en)(3)](3+) with the Delta or Lambda enantiomer and cyclotriphosphate anion are alternately arrayed and connected by multiple hydrogen bonds to form a homochiral column structure. Adjacent homochiral columns with different chirality for 1 are connected by intercolumn hydrogen bonds through P(3)O(9)(3)(-) anions, as the bridging groups, to form a tetrameric cyclic cylindrical structure, while the adjacent columns with the same chirality are connected for 2 to form the cyclic cylindrical structure. All 6 amino groups per [Co(en)(3)](3+) participate in the formation of 12 hydrogen bonds, in which 8 hydrogen bonds contribute to the construction of a homochiral column and the remaining 4 hydrogen bonds contribute to the intercolumn interactions. The circular dichroism spectrum of the aqueous solution of Lambda-[Co(en)(3)](3+) changes drastically when excess P(3)O(9)(3)(-) is added, and this change is explained by ion-pair formation. The thermodynamic association constant of [Co(en)(3)](3+) with P(3)O(9)(3)(-), calculated from the conductivity data, was log K = 4.26 at 25 degrees C.

The alkaline hydrolysis of diphosphate, triphosphate and cyclo-triphosphate sorbed into anion-exchange resins has been investigated using 3 1 P NMR spectroscopy. Well resolved 31P NMR spectra of the sample species and their hydrolysis products within the resin phase were observed. For diphosphate and triphosphate systems, the rate constant and activation parameters for each hydrolysis reaction are quite similar, both in the resin phase and in a basic solution. For the cyclo-triphosphate system, however, the hydrolysis is significantly retarded compared to that in a solution of tetramethylammonium hydrottide. This retardation is shown to be entirely due to a much more unfavourable A H f for the reaction in the resin phase. The relationship between mechanisms and reactivities of the hydrolysis in the resin phase is discussed.