Molecular recognition of octadecanyl ester of 1-(2-carboxyethyl)thymine to adenine at the air/water interface and photodimerization in the Langmuir-Blodgett film matrix under ultraviolet irradiation

A new single-chain nucleic acid base-containing amphiphile, octadecanyl ester of 1-(2-carboxyethyl)thymine, was synthesized, and its surface behaviors on pure water and on aqueous solutions of adenine were investigated by the method of surface pressure-area (pi-A) isotherms. Molecular recognition through complementary base pairing takes place at the air/water interface between the thymine moiety in the headgroup of the amphiphile and adenine, which results in the pick-up of the base-base complex onto quartz plate by the Langmuir-Blodgett (LB) technique. Photodimerization of thymine rings was also investigated in the multilayer LB film of the amphiphile deposited from pure water surface, and the results show that the orderly and regular packing of the molecules in the LB matrix provides favorable conditions for the formation of thymine dimers.