NMR studies of phosphonate carbanions: Influence of substituents on 1J(PC) and 1J(CH) and some INDO calculations

✍ Scribed by G. A. Webb; M.-P. Simonnin; J. Seyden-Penne; T. Bottin-Strzalko

• Publisher: John Wiley and Sons
• Year: 1985
• Tongue: English
• Weight: 324 KB
• Volume: 23
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1260230113

✦ Synopsis

C and "P NMR data are reported for a series of phosphonate carbanions. In comparison with related uncharged molecules, the values of 'J(PC) are rather large. This is discussed with the help of some INDOSCPT spin-spin coupling calculations, which reveal that while the positive contact term makes the dominant contribution to these couplings, the negative orbital term also plays an important role. The signs of 'J(PC) and 'J(CH) are predicted to be positive in all cases. Support for the proposal of a planar anionic carbon atom is forthcoming from the INDO-SCPT calculations.