1H,117 Sn J-HMBC spectroscopy as a tool for the determination of long-range nJ (1H,117Sn) coupling constants in the investigation of intramolecular donor–acceptor interaction in [2-(N,N-dimethylaminomethyl)phenyl]stannanes

✍ Scribed by M. Biesemans; J. C. Martins; R. Willem; A. Lyčka; A. Růžička; J. Holeček

• Publisher: John Wiley and Sons
• Year: 2001
• Tongue: English
• Weight: 131 KB
• Volume: 40
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.976

✦ Synopsis

Abstract

^1^H, ^117^Sn J‐HMBC spectroscopy was implemented as a tool for the determination of long range ^n^J(^1^H, ^117^Sn) coupling constants of [2‐(N,N‐dimethylaminomethyl)phenyl]stannanes, ArR~1~R~2~R~3~Sn or Ar~2~R~1~R~2~Sn, where R~1~, R~2~ and R~3~ are Ph or n‐Bu, and/or Cl or Br. It is demonstrated that coupling constants which are too small to be measured from multiplet splittings in the ^1^H or ^117^Sn spectra can be measured from the development of the sine modulation of the intensity of the ^1^H, ^117^Sn HMBC correlation peaks as a function of the incremented preparation time of the ^1^H,^117^Sn HMBC pulse sequence. It is examined whether such couplings can be used as straightforward indicators for the existence of intramolecular nitrogen–tin interactions. While some coupling constants are shown to depend on the strength of the above‐mentioned interaction, it is also demonstrated that ^6^J(^1^H,^117^Sn) coupling constants between the N‐methyl groups and the tin nucleus can be observed even in structures where no nitrogen–tin interactions are possible. Copyright © 2001 John Wiley & Sons, Ltd.