Showing papers by "Willis B. Person published in 1987"
Journal Article•
TL;DR: Experimental evidence, as well as the quantum-mechanical calculations, clearly indicate that two tautomers of cytosine, i.e. the amino-hydroxy and amino-oxo forms with the hydrogen atom at the N(1) position, exist in equilibrium when the cytOSine molecule is isolated in an inert environment.
Abstract: Tautomerism of the cytosine molecule is discussed in connection with recent experimental matrix-isolation infrared spectroscopic measurements and recent ab initio calculations of relative stabilities of tautomers and of IR spectra for different tautomeric forms of the compound. Experimental IR spectra in the N-H and O-H stretching regions and in the C = O stretching region are presented for cytosine and for its several derivatives considered as model compounds. This experimental evidence, as well as the quantum-mechanical calculations (including both electron correlation and zero-point vibrational contributions), clearly indicate that two tautomers of cytosine, i.e. the amino-hydroxy and amino-oxo forms with the hydrogen atom at the N(1) position, exist in equilibrium when the cytosine molecule is isolated in an inert environment. The effect of the environment on the relative stabilities of several tautomers is also discussed briefly.
24 citations
TL;DR: In this article, the SCF results in polarized basis sets are believed to be sufficiently accurate to suggest that the cis form of H2POH was that observed in the matrix rather than the trans form.
20 citations
TL;DR: In this paper, the conformation of the dilithioacetylene molecule has been investigated up to the CCSD+T(CCSD) level with the 6-311G*(*) basis.
Abstract: The conformation of the dilithioacetylene molecule has been investigated up to the CCSD+T(CCSD) level with the 6-311G*(*) basis. The geometry of the molecule has been fully optimized on the SCF and MBPT(2) levels with a variety of basis sets. It has been found that the equilibrium geometry is rather sensitive to the choice of the basis. Calculations on the CCSD+T(CCSD) level have shown that, although the second-order MBPT energy term destabilized the planar structure, the sum of the higher order corrections slightly stabilized this form. The planar doubly bridged (D2h) structure is predicted to be the most stable one.
1 citations