13C Showing J Coupling to Both 31P and 14N

Despite my efforts, some novice users still believe that all ¹³C resonances are sharp singlets. This is indeed the case in proton decoupled ¹³C spectra where there is no additional heteronuclear coupling, exchange or fast relaxation. In the BLOG entries for December 11, 2007 and October 9, 2007 , I showed ¹³C NMR spectra where the carbon was coupled to ¹⁴N and ¹⁹F, respectively. The spectrum below is a ¹³C spectrum where ¹³C couples with ³¹P and ¹⁴N. The yellow region of the full spectrum is expanded in the inset. Carbon 2 is particularly interesting as it shows coupling to both ³¹P and ¹⁴ N.