HYDRATION STRUCTURE OF URACIL AS STUDIED BY 1D AND 2D HETERONUCLEAR OVERHAUSER SPECTROSCOPY - EVIDENCE FOR THE FORMATION OF A TRIHYDRATE INTHE FIRST SOLVATION SHELL
M. Chahinian et al., HYDRATION STRUCTURE OF URACIL AS STUDIED BY 1D AND 2D HETERONUCLEAR OVERHAUSER SPECTROSCOPY - EVIDENCE FOR THE FORMATION OF A TRIHYDRATE INTHE FIRST SOLVATION SHELL, Chemical physics letters, 285(5-6), 1998, pp. 337-345
The intermolecular heteronuclear Overhauser effect (HOE) between water
and uracil has been measured. Steady-state C-13, H-1 nuclear Overhaus
er effect (NOE) results show that the first solvation shell includes t
hree water molecules. Transient C-13, H-1 and N-15, H-1 2D HOESY exper
iments as well as H-1 NOESY experiments give further evidence for the
formation of a cyclic trihydrate as obtained by three bridge hydrogen-
bonding between the three water molecules and the two amide groups of
the uracil. The trihydrate has only a very short life-time as compared
to the rotational correlation time of the free uracil molecule which
remains the tumbling species in the water-DMSO solution. (C) 1998 Else
vier Science B.V.