ИСТИНА

Dynamic behavior of molecular systems is normally associated with some sort of chemical reactions. There are still numerous examples of extremely rapid dynamics, which can not be described with reaction rates, activation parameters etc. It even is better to consider them in terms of vibrations with large amplitude. Accurate structure studies of saturated four- and five-membered cycles imply solving specific problem of quantitative description of dynamic processes with very low barriers in them. Examples of accurate microwave studies are known of only few simplest such systems in gaze phase. We developed a practical method for evaluation of the parameters of conformational dynamics in terms of vibrations with large amplitude. The method based on: (i) the results of complete analysis of high resolution NMR spectra, (ii) ab’initio calculations of a reaction path and surfaces of potential energy and spin-spin coupling constants, (iii) a numerical solution of corresponding vibration problem and (iv) refinement for the parameters of the energy surface based on the best fit of experimental and calculated spin-spin couplings. Advantages of the technique developed demonstrated on number of model systems dissolved in regular solvents.