NMR shift reagents for organic salts: Shift mechanism, bound shifts and structural analysis

✍ Scribed by Thomas J. Wenzel; Kirk Cameron

• Book ID: 102951373
• Publisher: John Wiley and Sons
• Year: 1989
• Tongue: English
• Weight: 547 KB
• Volume: 27
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1260270805

✦ Synopsis

Lanthanide tetrakis(/l-diketonate) anions are effective NMR shift reagents for organic salts. The shifts in the 'H NMR spectra were analyzed and explained without invoking a contact shift mechanism. The equilibria of the shift reagentsubstrate complex was examined. No evidence was found for a 1:2 shift reagentsubstrate complex. Bound shifts and association constants were determined for 1-methyltetrahydrothiophenium iodide (1) and 1ethylquinolinium (3) iodide. The observed shifts for these salts were fitted to calculated shifts using the simplified dipolar shift equation. A single lanthanide location was identified with 3. A time average of at least two configurations of shift reagentsubstrate complex was required with 1.