Indirect detection of the 183W and 57Fe nuclei using 119Sn-relayed 1H,X correlation spectroscopy.

Recently reported triple-resonance Y-relayed (1)H,X correlation experiments have been utilized to characterize (183)W and (57)Fe chemical shifts using (119)Sn as the Y-relaying nucleus instead of the previously used (31)P. Application of an adaptation of Gudat's original INEPT/HMQC sequence results in a significant enhancement of the signal-to-noise (S/N) ratio for two-dimensional (119)Sn-relayed (1)H,(183)W and (1)H, (57)Fe correlation spectra with efficient detection of the transition metal nucleus in tungsten and iron complexes lacking an observable direct scalar coupling between the transition metal and any hydrogen nuclei. Strengths and shortcomings of the novel sequence and the original sequences reported by Gudat are discussed in the context of (119)Sn-relayed proton detection of very low frequency transition metal nuclei. 2010 John Wiley & Sons, Ltd.