Hyperpolarization of quadrupolar 14N nuclei was demonstrated for the first time. This was achieved using pairwise addition of parahydrogen to tetraalkylammonium salts with vinyl or allyl moieties followed by polarization transfer from 1H to 14N nuclei using PH-INEPT pulse sequence. After optimization of interpulse delays by both simulations and experiments, up to 760-fold signal enhancement at 7 T
首次证明了四极14 N 核的超极化。这是通过将仲氢成对加成到具有
乙烯基或烯丙基部分的四烷基
铵盐上,然后使用 PH-I
NEPT 脉冲序列从1 H 原子核极化转移到14 N 原子核来实现的。通过仿真和实验对脉冲间延迟进行优化后,在 7 T 下获得了高达 760 倍的信号增强。