Synthesis and characterization of dicyanoanthracene-tethered β-cyclodextrins

Abstract

The synthesis of 6-O- and 2-O-(9,10-dicyanoanthracene-2-methyl)-β-cyclodextrin (1 and 2) is described. Binding affinities with several aromatic sulfonate guests (6–10) are determined using fluorescence quenching results. The apparent Stern–Volmer constants, which are the sums of dynamic and static (binding) components, are adjusted by subtracting those obtained in the presence of 1-adamantanecarboxylate (AD–CO₂^–) which have just a dynamic term. Quenching constants with 9,10-dicyanoanthracene-2-sulfonate (4) and 9,10-dicyanoanthracene-2,6-disulfonate (5), and binding constants with β-CD are determined for comparison. The results show that the C6 tethered host binds better than the C2 host, which binds as well as does β-CD. Dynamic quenching accounts for at least 10% of the total even with strongly bound guests. The properties of these hosts are compared with a DCA-capped β-CD (3)(DCA = dicyanoanthracene).