N-15 NUCLEAR MAGNETIC-RESONANCE SPECTROSCOPY - EFFECTS OF HYDROGEN-BONDING AND PROTONATION ON NITROGEN CHEMICAL-SHIFTS IN IMIDAZOLES

被引：75

作者：

SCHUSTER, II ^{[1
]}

ROBERTS, JD ^{[1
]}

机构：

[1] CALTECH,GATES & CRELLIN LABS CHEM,PASADENA,CA 91125

来源：

JOURNAL OF ORGANIC CHEMISTRY | 1979年 / 44卷 / 22期

关键词：

D O I：

10.1021/jo01336a025

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

The 15N chemical shifts of imidazoles, N-methylimidazole and 4-methylimidazole, have been measured in acidic and neutral nonaqueous media. Both hydrogen bonding and protonation of the imidazoles result in upfield shifts of the average of the nitrogen resonances, but the magnitudes of the protonation shifts far exceed those associated with hydrogen bonding. The less-than-normal shifts of the imidazolium ions in nonaqueous media suggest ion-pair formation resulting from interion hydrogen bonding. Such effects diminish in solvents of higher dielectric constant and greater solvating power for salts. © 1979, American Chemical Society. All rights reserved.

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页码：3864 / 3867

页数：4

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