March 10, 2008
by Arvin Moser, Team Manager, Application Scientists, ACD/Labs
1H-1H couplings arise from influences on a proton’s magnetic field induced by the magnetic field of a neighbouring proton(s). As a proton experiences coupling from a neighbouring proton, so too is the coupling reciprocated to the neighbouring proton(s). By measuring the J-coupling for each splitting pattern, the proton connectivity information can be deduced.
By comparing the J-coupling for each splitting pattern in the 1H NMR below, roughly +/- 0.2 Hz, one can determine which multiplets pair up. Based on the pairing information, we can deduce that the proton is within proximity of its pair.
Coupled protons are:
Multiplets A and C = green line
Multiplets B and C = orange line
Multiplets D and C = purple line.
Multiplets E and C = red line.
Multiplets D and E = black line.
Excuse me, from this NMR spectrum, what is the structure or the molecules do they come from? Thank you very much.
Hello Arwika,
Thank you for your interest in my blog. The compound is similar to the one posted here http://blog.acdlabs.com/elucidation/2008/10/anisochronous-p.html . When dealing with unknown compounds, it is best to look at NMR and MS data. This also includes database searches such as outlined here http://pubs.rsc.org/is/content/articlelanding/2015/ob/c5ob01713k#!divAbstract .
Regards,
Arvin Moser, M.Sc.