A simple electrostatic model of solvation for large molecules within the SCF MO theory

Why isoguanine and isocytosine are not the components of the genetic code

“…2) Comparing experimental data for relative stability of the cytosine tautomers [ 121, which indicate the predominance of the tautomer C over C* by a factor of 104-105, experimental data for isocytosine [ 12,151, with theoretical estimations for the tautomers of both compounds, as well as considering environmental effects on the change of tautomeric equilibria on going from the vapor phase to another medium, e.g., to water solution (see, e.g., [16,18]), it is evident that the ratio of the isoC* forms to the isoC ones is much larger than the corresponding ratio for cytosine.…”

Applied quantum chemistry

“…Net atomic charges obtained by Mulliken population analysis cannot be used directly in most cases; but Mulliken charges, scaled in such a way that they reproduce the total dipole moment of the solvent molecules, have proved to be adequate in many cases [1025]. The electrostatic effect of the water molecules in the cybotactic region has also been represented by appropriately selected point dipoles, the potential of which had been included directly in the Fock operator of the solute [91,1441].…”

“…Hydration of more complicated solutes like organic molecules [91,248,273,835,1146] and biomacromolecules [228,1068] is also studied by Monte Carlo methods. Beveridge and coworkers [895] performed such a calculation for glyoxal (HCO)2 and they characterized the coordination of the various atoms.…”

Józef Stanislaw (“Staszek”) Kwiatkowski, (1936 to 2000)

“…In the years between 1974 and 1980, in collaboration with a number of individuals, Staszek became involved in theoretical studies of several aspects of the tautomeric equilibria of heterocyclic compounds. In particular, they performed studies of the water environmental effect on the tautomeric equilibrium 15–21. Together with Pullman 14 and Lesyng 22 he carried out π‐SCF MO CI calculations for different tautomeric forms of N‐heterocyclic compounds substituted by simple donor groups.…”