ISSN:
0749-1581
Keywords:
1H NMR chemical shifts
;
Purine-pyrimidine aqueous systems
;
Self-association
;
Hetero-association
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The association behaviour of purine and pyrimidine has been studied in deuterium oxide at 35°C by measuring the concentration-dependent selective changes in the chemical shifts of the CH protons. A satisfactory interpretation of the cross-interaction, i.e. the mutually induced upfield shifts in mixed solution, required the extension of the 1:1 hetero-association model by taking into account the self-association of both compounds. The self-association and the hetero-association parameters have been determined on the basis of two-state and three-state models. The equilibrium constants give a decreasing tendency for association within the series purine-purine (0.82 ± 0.08 1 mol-1) 〉 purine-pyrimidine (0.54 ± 0.06 1 mol-1) 〉 pyrimidine-pyrimidine (0.050 ± 0.002 1 mol-1), and the values of the dimer upfield shifts suggest that the association processes are dominated by the interaction of the six-membered rings.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1260251013
