Precise recognition of nucleic acid bases by polymeric receptors in methanol. Predominance of hydrogen bonding over apolar interactions

In methanol, poly(2-vinyl-4,6-diamino-1,3,5-triazine) (PVDAT) precisely recognizes nucleic acid bases and their derivatives through hydrogen-bond formation, The binding activity (uracil, thymine much greater than cytosine, adenine > pyrimidine, purine is approximately equal to 0) exactly coincides with increasing number in the complementary hydrogen-bonding sites of the guest towards the diaminotriazine residue. The guest-selectivity is higher than that achieved previously in water (H. Asanuma et al., Macromolecules, 1998, 31, 371), mainly because the guest-binding occurs mostly via the hydrogen bonding at aprotic sites provided by the polymeric receptor, Stacking and apolar interactions are ineffective in methanol, The copolymers of 2-vinyl-4,6-diamino-1,3,5-triazine with hydrophobic monomers (styrene and 4-vinylbiphenyl) show still higher guest-selectivities, due to the increased aprotic environment around the diaminotriazine residues.