Afr. J. Chem. 01/2011; 64:23.
Journal of Molecular Spectroscopy. 01/2010; 261:73.
ABSTRACT: An experimental and theoretical RHF, MP2 and DFT/6-31++G** study is described of the matrix FT-IR spectra of monomer 2-aminopurine and H-bonded complexes of 2-aminopurine with water.
2-aminopurine occurs in Ar predominantly as the amino-N9H tautomer, but small amounts of the amino-N7H tautomer are also present.
An approximate KT value for this tautomeric equilibrium is found to be 0.016 (RHF) and 0.015 (DFT) using the infrared intensity measurement.
Four H-bonded complexes of the abundant amino-N9H form with water are detected in the experimental FT-IR spectrum by their
characteristic predicted absorptions, i.e. the three closed complexes N3 ... H-O ... H-N9, N1 ... H-O ... H-NH, N3 ... H-O ... H-NH and the open complex N7 ... H-OH. From the experimental results, the proton affinity of the N7 atom in 2-aminopurine can be estimated. The dependence
of the H-bond strength on the H-bond linearity is demonstrated by a correlation between the N ... H distance and the N ... H-O angle in closed N ... H-O ... H-N complexes.
The European Physical Journal D 01/2002; 20(3):375-388. · 1.48 Impact Factor