Proton spin-lattice relaxation rate studies. 1-Aryl-4,4-dimethyl-2-methylthio-2-imidazolin-5-ones

✍ Scribed by Jean-Marie Navarre; Lawrence D. Colebrook; Laurance D. Hall

• Book ID: 102530315
• Publisher: John Wiley and Sons
• Year: 1980
• Tongue: English
• Weight: 494 KB
• Volume: 14
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1270140517

✦ Synopsis

Abstract

Proton spin‐lattice relaxation rates (R~1~ values) have been measured, at 270 MHz, for a series of 1‐aryl‐4,4‐dimethyl‐2‐methylthio‐2‐imidazolin‐5‐ones, using both null‐point and non‐linear regression methods; the two procedures give the same rates. A normalization procedure has been used to enable comparisons to be made between the R~1~ values of different compounds; this is necessary because the experimental values are affected by changes in motional correlation times associated with changes in molecular structure. A substantial (five‐fold) dynamic range of R~1~ values has been observed for the protons of individual compounds, and the values have been correlated with the molecular environments of the nuclei. Evidence for anisotropic molecular motion and inter‐ring proton relaxation in these compounds has been considered.