INTRAMOLECULAR WEAK INTERACTIONS IN METHYL RED CONFORMERS

Solvent interactions stabilising nucleic acid conformers.

The transition of oligonucleotides from the B to the A conformation has been studied by the use of simple geometric calculations aimed at finding possible hydration sites which could stabilize these conformations. The method involves the classification of equally spaced grid points, surrounding the oligonucleotide, into groups depending on whether a water molecule, so placed, could form single,...

Enhancement of cyclization quantum yields of perfluorodiarylethenes via weak intramolecular interactions.

The weak intramolecular F∙∙∙N and S∙∙∙N interactions in the novel pyridine-containing perfluorodiarylethenes achieved high cyclization quantum yields in solutions. While the F∙∙∙N interactions stabilize the photoreactive conformation, the S∙∙∙N contacts contribute from the energetic aspect.

A repertoire of pyridinium-phenyl-methyl cross-talk through a cascade of intramolecular electrostatic interactions.

Direct intramolecular cation-pi interaction between phenyl and pyridinium moieties in 1a(+) has been experimentally evidenced through pH-dependent (1)H NMR titration. The basicity of the pyridinyl group (pK(a) 2.9) in 1a can be measured both from the pH-dependent chemical shifts of the pyridinyl protons as well as from the protons of the neighboring phenyl and methyl groups as a result of elect...

Weak Interactions*

Inter- and intramolecular dispersion interactions

We have investigated the performance of a variety of density functional methods for weak intra- and intermolecular dispersion interactions. Grimme's empirical dispersion correction method is shown to give a good description for these interactions and helps to improve the description of water-hexamer isomers, noble-gas dimers, hydrocarbon C(12)H(12) isomers, branching energy of linear versus bra...