Spin polarization transfer simulations of lactate ester molecules

Abstract

The signal received from Nuclear Magnetic resonance (NMR) is inherently weak. Hence, it is of interest to amplify the signal. The signal amplification would make the experimental NMR results more precise, meaning that detecting molecules or atomic groups in molecules would be easier. I carry out spin dynamics simulations on lactate ester molecules using DFT-computed spin-spin coupling networks for the spin systems and investigate the transmission of spin density from the initially fully polarized OH proton to the other 1H- and 13C-nuclei in the systems. I investigate the effects of the coherent and incoherent dynamics on the polarization transfer. The simulation results indicate that the hydrogens and carbons in the molecule after the link oxygen (the side of the molecule without the OH-group, when the link oxygen is in the middle) do not have an impact on the polarization of 13C, but the polarization from maximally polarized OH proton does flow to other protons, including the protons after the link oxygen. The simulations also show that the applied incoherent dynamics do not affect the spin polarization transfer to 13C. The results show that the simulations are not yet sophisticated enough and need changes so that they will resemble experimental results more closely, and that the applied relaxation and full molecular model simulations work as intended.