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Dynamic behavior of molecular systems is regularly associated with some sort of chemical reactions. There are still numerous examples of extremely rapid dynamics, which can’t be sufficiently evaluated in terms of classical kinetic parameters. Accurate structure studies of open-chain compounds and saturated four- and five-membered cycles imply solving specific problem of quantitative description of dynamic processes with very low barriers. 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) complete analysis of high resolution NMR spectra, (ii) ab’initio calculations of a reaction path and surfaces of spin-spin coupling constants, (iii) a numerical solution of vibration problem and (iv) refinement for the parameters of the potentials based on the best fit of experimental and calculated spin-spin couplings (see e.g. [1-2]). Advantages of the technique demonstrated on studies of pseudorotation in four- and five-membered cycles and internal rotation in acyclic systems: natural endogenic hormone adrenaline, styrene and substituted azobenzenes.