USE OF A LANTHANIDE SHIFT-REAGENT FOR SIMPLIFIED NMR ANALYSIS OF BORNEOL - ISOBORNEOL MIXTURES - APPARENT CATALYSIS OF OH PROTON-EXCHANGE BY LSR

被引：1

作者：

BENSHAFRUT, R ^{[1
]}

ROTHCHILD, R ^{[1
]}

机构：

[1] CUNY JOHN JAY COLL CRIMINAL JUSTICE,DEPT SCI,CTR TOXICOL RES & TRAINING,445 W 59TH ST,NEW YORK,NY 10019

来源：

SPECTROSCOPY LETTERS | 1992年 / 25卷 / 03期

基金：

美国国家科学基金会;

关键词：

H-1-NMR; EUROPIUM; EU(FOD)3; EXCHANGE DECOUPLING; STERIC HINDRANCE; LSR;

D O I：

10.1080/00387019208018200

中图分类号：

O433 [光谱学];

学科分类号：

0703 ; 070302 ;

摘要：

The use of H-1 NMR at low field (60 MHz spectrometer frequency) for direct analysis of mixtures of borneol, 1, and isoborneol, 2, is considerably simplified by addition of the lanthanide shift reagent (LSR), tris(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionato)europium(III), 3. The effect of added 3 is twofold. Firstly, the analytical marker signals of the methine proton CHOH in 1 and 2, which are partly overlapped at 60 MHz in CDCl3 (28-degrees), are separated and rendered baseline-resolved due to preferential LSR binding to the less hindered endo OH of 1. Secondly, the absorption signals of the CHOH methines actually sharpen in the presence of 3, and display clearly defined multiplet structure, attributed to full exchange decoupling of the vicinal OH as a result of enhanced OH exchange rates when LSR is present.

引用

页码：433 / 446

页数：14