Interaction of adenosine with alkyltrimethylammonium bromides

The interaction of adenosine with alkyltrimethylammonium bromides, C_mH_2m+1N(CH₃)₃Br(m=16, 14, 12, 10, 8, and 6), has been studied by 1 H NMR spectroscopy. When surfactants exist as monomer units, the adenine ring of adenosine preferentially associates with the middle portion of the alkyl chain of the surfactants. The interaction is less specific with surfactants of shorter alkyl chains. When surfactants form micelles, no specific interaction between the adenine ring and the alkyl chain of the surfactant can be detected. A coordination of the cationic part of the surfactants with the adenine ring is suggested. The degree of association was evaluated from association constants. Similar results were obtained for purine and alkyltrimethylammonium bromide.