Thioether macrocyclic complexes 15 aneS

It is of interest now to consider the kinetics of complex formation (kf) and dissociation (kd) of chelate, macrocyclic, and cryptate complexes and how these are related to the type of ligand stmcture. Table 10 lists kf and kj valnes for chelating ( 1-3), macrocyclic ( 4 and 5), and cryptand ( 6-8) ligands and the appropriate reference compounds. For the chelate effect, the reactions of Ni " with py, bipy, and terpy show very little difference in kf values. On the other hand, the valnes of kj decrease by factors of 2 x 10 and 2 X 10, for bipy and terpy, respectively. A similar effect is seen in a comparison of the reactions of Cn + ion with the thioether macrocycle [14]aneS4 (ane denoting a saturated carbon macrocycle and S4 (he four sulfur donor atoms) and its acyclic... 

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