Measurement of the sign and the magnitude of small heteronuclear coupling constants

SeRMN seminar

  • Date:  Friday 10th May, 2013
  • Hour: 10 am
  • Location:  SeRMN,  Facultats de Ciències i Biociències, C2/-135
  • Speaker:  Josep Saurí, SeRMN PhD Student

The design of NMR methods directed to the measurement of heteronuclear coupling constants in small molecules has been the subject of great interest. However, there have always been doubts about the correct choice of the best NMR method to be used and many discussions have focused on the accuracy, reliability, and simplicity of the data analysis and determination of the nJ(CH) coupling constant. Despite the extensive number of NMR techniques that have been developed, there are still two unsolved experimental problems pertaining basically to non-protonated carbon atoms, namely, a) an accurate measurement of very small coupling constants (less than 2–3 Hz) and b) the absence of a general and robust approach to determine the sign of the coupling constant.

In this seminar, a new approach to measure the sign and the magnitude of small heteronuclear coupling constants in protonated and non-protonated centers will be described. Furthermore, the effects of J(HH) modulation —which is one of the most important drawbacks in this kind of measurements— will be experimentally evaluated.