苯并氮杂冠醚化合物在氘代氯仿中的溶剂效应的动态1H NMR研究

本文讨论了样品浓度对苯并氮杂冠醚化合物-氘代氯仿溶液~1H NMR镨及~1H纵向弛豫时间的影响(稀释位移效应)。在实验基础上提出了苯并氮杂冠醚化合物在氯仿中的叔胺-叔铵盐交换作用机制。以此馐土讼∈臀灰菩в? 并得到巳止诿鸦衔锎邮灏返绞屣а蔚姆从ζ胶獬Ｊ齂_2和交换速率常数k, 另外, 本文还讨论了冠醚环中氮原子上取代基对稀释位移效应的影响,

DYNAMIC 1H NMR STUDIES OF SOLVENT EFFECT FOR BENZO-AZACROWN-ETHERS IN CDCl3 SOLUTIONS

The influences (Dilution Shift Effect) of sample concentration on ~1H NMR spectra and spin-lattice relaxation times in benzo-azacrown-ether (CE) -CDCl_3 solutions were discussed in this paper. It was considered that the formation of hydrogen bond complex between CE and CDCl_3 is not the major cause leading to Dilution Shift Effect. Based on experiments, a reaction mechanism for CE in CDCl_3-“tertiary amine-tertiary amino salt exchange” was proposed, which has successfully explained the Dilution Shift Effect. The equilibrium constants K_2(2.2±0.4)×10~(-2) mol L~(-1), (1.9±0.4)×10~(-2) mol L~(-1) and (1.3±0.4)×10~(-2) mol L~(-1) respectively] and exchange rate constants k4500±1000 s~(-1), 15000±3000 s~(-1) and 6000±1500 s~(-1) respectively] for this mechanism of “tertiary amine-tertiary amino salt exchange” of I, II and III (see experimental section) were obtained through simulation of chemical shift and line shape of ~1H NMR spectra of CE in CDCl_3. Also, the effects of substitute groups of α—C to N on the Dilution Shift Effect were discussed.