基于固体核磁共振技术的固体酸结构、酸性及活性分析

杨文杰,黄骏

Analysis of Local Structure, Acidic Property and Activity of Solid Acids by Solid-State Nuclear Magnetic Resonance Spectroscopy

Wen-jie YANG,Jun HUANG

表2 部分常用探针分子以及基于化学位移变化的酸位特性判定

Table 2 Some commonly used probe molecules and the chemical shift changes-based characterization of acid site

Probe molecules Strength of BAS Strength of LAS Reference Deuterated acetonitrile (CD3CN) δH: 3.6 $ \to $ 9.6 Weak $ \to $ Strong / [66] Pyridine-d5 (C5D5N) δH: 12 $ \to $ 20 Strong $ \to $ Weak / [69, 70] Acetone-2-13C ((CH3)213CO) δC: 216 $ \to $ 235 Weak $ \to $ Strong δC: 233 $ \to $ 250 Weak $ \to $ Strong Super acid* with δC≥ 245 [31, 71, 72] 15N-pyridine δN: 212 $ \to $ 288 Strong $ \to $ Weak δN: 260 $ \to $ 285 Strong $ \to $ Weak [73] Trimethylphosphine oxide (TMPO) δP: 55 $ \to $ 86 Weak $ \to $ Strong δP: 37 $ \to $ 55 Weak $ \to $ Strong [64, 74] Trimethylphosphine (TMP) δP: -2 $ \to $ -5 Larger J-coupling constant between 31P and 1H $ \to $ Stronger acid δP: -13 ~ -52 δP depends on Lewis centers, for identical Lewis centers, smaller δP $ \to $ Stronger acid [61, 65, 74]