Passive observation of 15N satellites in two‐dimensional heteronuclear X–1H shift‐correlated spectra via a Hahn spin–echo extended pulse sequence

The application of a Hahn spin–echo extended X–1H shift‐correlated (X = 13C, 29Si, 119Sn, 207Pb) two‐dimensional NMR technique to carbon–, silicon–, tin– and lead–nitrogen compounds is described. This allows complete suppression of the central line (representing the isotopomer with 14N), leaving solely the 15N satellites in the two‐dimensional spectrum leading both to accurate measurement of long‐range 15N1H spin–spin coupling constants and to the determination of the relative signs of the 15NX and 15N1H couplings. 15N/14N isotope effects on 119Sn and 207Pb chemical shifts were measured apparently for the first time.