中文摘要：

采用连续流动的激光诱导超极化129Xe为探针分子,利用高分辨固体核磁共振技术研究了不同电子结构的金属阳离子（Na^＋,Ag^＋,Cu^2＋,Cu^＋,Cs^＋）交换的FAU型分子筛与超极化129Xe之间的相互作用.结果表明,超极化129Xe能够很灵敏地检测不同电子结构的金属离子对限阈空间中电场梯度的影响.Na^＋对超笼内电场梯度的影响很小,NaX与NaY分子筛中Xe的化学位移表现出相似的行为.对于具有nd10电子结构的Ag＋或Cu^2＋经自还原生成的Cu^＋,其与Xe的5d0轨道形成dπ-dπ键,导致Xe的化学位移明显向高场方向位移.Cu^2＋由于具有一定的顺磁性,使得129XeNMR谱展宽,甚至无法观测.Cs^＋的电子结构与Xe原子相同,它能吸附更多的Xe原子,导致Xe的化学位移明显向低场方向偏移.

英文摘要：

Continuous-flow hyperpolarized 129Xe NMR was used to investigate the influence of metal cation-exchanged faujasite （FAU） zeolites on the 129Xe chemical shift. 129Xe is a sensitive probe molecule to detect the local electric field in a confined space originating from substituted metal cations with different electronic structures such as Na＋, Ag＋, Cu＋, Cu2＋, and Cs＋. It is found that Na＋ has less effect on the electric field gradient of the supercage in FAU zeolites. The chemical shifts of Xe in NaX and NaY have similar behavior. For cation with thend^10 electronic structure such as Ag^＋ or Cu^＋, there is specific dπ-dπ interaction between metal cations and the Xe atom, which leads to the upfield of Xe chemical shift. For Cu^2＋, its partial paramagnetism results in the broadening of Xe NMR spectra or even disappearance of the 129Xe signal in the supercage. For Cs^＋, whose cation has the same electronic structure as the Xe atom, it may adsorb more Xe atoms in the supercage of FAU zeolites, leading to the downfield of Xe chemical shift.