13C nuclear magnetic resonance of organophosphorus compounds XI—aminophosphines

✍ Scribed by George A. Gray; John H. Nelson

• Publisher: John Wiley and Sons
• Year: 1980
• Tongue: English
• Weight: 435 KB
• Volume: 14
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1270140103

✦ Synopsis

Abstract

Natural abundance ^13^C NMR studies have been carried out on a series of organophosphorus compounds possessing PN bonds. For the first time a one‐bond temperature‐dependent ^13^C—^31^P nuclear spin coupling was observed for the P‐phenyl carbons in bis(N,N‐dibenzylamino)phenylphosphine (0‐9 Hz) and bis(N,N‐diethylamino)phenylphosphine (0–2 Hz). This temperature‐dependent behavior can be rationalized in terms of free rotation about the phenyl phosphorus bond with concomitant hindered rotation about the PN bonds. A conformational preference for the nitrogen and phosphorus lone pairs to exist in the trans orientation is indicated. In the similarly substituted 5‐membered heterocyclic ring compound, 1,3‐dimethyl‐2‐phenyl‐1,3‐diazaphospholidine, the phenyl one‐bond coupling increases to (−) 42.1 Hz and becomes temperature independent. These data suggest that ^1^J(PC) is very responsive to electronic effects.