title: Stacking interactions of nucleobases: NMR-investigations. II. Self-association of purine-and pyrimidine-derivatives.
abstract: The self-association of various purine- and pyrimidine-derivatives in D2O has been studied by means of NMR technique. The thermodynamic quantities have been calculated using an isodesmic NMR model. Among the nucleobases investigated, the adenine-derivatives were found to be most suitable for quantitative determination. A comparison of methylated adenine-derivatives and the pH-dependence of the self-association lead to the conlcusion, that the stacking associates are stabilized by special van der Waals interactions based, essentially, on the polarizability of the pi-electron-system of the assciated molecules.
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives; D000241:Adenosine / Q000031:analogs & derivatives; D002110:Caffeine; D055598:Chemical Phenomena; D002621:Chemistry; D003596:Cytosine / Q000031:analogs & derivatives; D003903:Deuterium; D007042:Hypoxanthines; D009682:Magnetic Resonance Spectroscopy; D011108:Polymers; D011687:Purines; D011743:Pyrimidines; D013816:Thermodynamics; D014498:Uracil / Q000031:analogs & derivatives; D014527:Uric Acid / Q000031:analogs & derivatives; D014867:Water
chemical_list: D007042:Hypoxanthines; D011108:Polymers; D011687:Purines; D011743:Pyrimidines; D014867:Water; D014527:Uric Acid; D002110:Caffeine; D014498:Uracil; D003596:Cytosine; D003903:Deuterium; D000225:Adenine; D000241:Adenosine