Dissolution dynamic nuclear polarization of deuterated molecules enhanced by cross-polarization

We present novel means to hyperpolarize deuterium nuclei in (CD2)-C-13 groups at cryogenic temperatures. The method is based on cross-polarization from H-1 to C-13 and does not require any radio-frequency fields applied to the deuterium nuclei. After rapid dissolution, a new class of long-lived spin states can be detected indirectly by C-13 NMR in solution. These long-lived states result from a sextet-triplet imbalance (STI) that involves the two equivalent deuterons with spin I = 1. An STI has similar properties as a triplet-singlet imbalance that can occur in systems with two equivalent I = 1/2 spins. Although the lifetimes TSTI are shorter than T-1(C-z), they can exceed the life-time T-1(D-z) of deuterium Zeeman magnetization by a factor of more than 20. Published by AIP Publishing