PHIP NMR Spectroscopy in Ionic Liquids: Influence of Salts on the Intensity of Polarization Signals

Abstract

Parahydrogen-induced dynamic nuclear polarization NMR spectroscopy (PHIP) in ionic liquids leads to weak or no polarization signals, depending on the type of experiment. We demonstrate that the intensity of polarization is directly correlated to the concentration of the ionic liquids. High ion concentration is connected to fast T1 relaxation, resulting in annihilation of the polarization signals.