DITOPIC BINDING OF NUCLEOTIDES BY KIS(6-HYDROXYETHYLAMINO-6-DEOXY)-BETA-CYCLODEXTRIN

The potential of heptakis(6-hydroxyethylamino-6-deoxy)-beta-(1) as a d itopic receptor capable of electrostatic interaction and hydrogen bond ing by its amino side-chains, together with inclusion in its hydrophob ic cavity, has been assessed for nucleotides as guest molecules. The i nteraction of 1 with adenosine-5'-triphosphate (ATP) and adenosine-5'- monophosphate (AMP) has been studied by potentiometry in water. Except ionally strong binding is observed for fully protonated 1 with ATP(4-) (K = 10(10) M-1) relative to AMP(2-) (K = 10(6) M-1), consistent with stronger electrostatic interaction with the former. Binding of AMP an d p-nitrophenyl phosphate is of the same order of magnitude, while the complexes formed with ribose-5-phosphate are much weaker, The NMR cha nges observed upon addition of the nucleotides to 1 confirm interactio n with the amino sites, together with inclusion in the cyclodextrin ca vity.