Calculated and experimental NMR chemical shifts of p-menthane-3,9-diols. Acombination of molecular dynamics and quantum mechanics to determine the structure and the solvent effects

NMR chemical shifts have been experimentally measured and theoretically est imated for all the carbon atoms of (LR,3S,4S,8S)-p-menthane-3,9-diol in chl oroform solution. Theoretical estimations were performed using a combinatio n of molecular dynamics simulations and quantum mechanical calculations. Mo lecular dynamics simulations were used to obtain the most populated conform ations of the (1R,3S:4S,8S)-p-menthane-3,9-diol as well as the distribution of the solvent molecules around it. Quantum mechanical calculations of NMR chemical shifts were performed on the most relevant conformations employin g the GIAO-DFT formalism. A special emphasis was put in evaluating the effe cts of the surrounding solvent molecules. For this purpose, supermolecule c alculations were performed on complexes constituted by the solute and n chl oroform molecules, where n ranges from 3 to 16. An excellent agreement with experimental data has been obtained following this computational strategy.