The use of complex wiggle-beat patterns for the estimation of small splittings in NMR spectra

Abstract

The analysis of the ‘wiggle-beat’ patterns produced by rapid passage through simple NMR multiplets is modified and extended to permit analysis of beats from multiplets where adjacent signals are not equally separated and where the intensities are not necessarily in the ratio of the appropriate binomial coefficients. The simple example of mono-silane-d₁ (SiH₃D) is illustrated: J _HD = 0·427 ± 0·003 c/s. Allowance is also made for the finite time of passage through the signal and the usefulness of this demonstrated by analysing the beat pattern from the asymmetric spectrum of a mixture of SiH₃D and SiH₄. In this way the SiH₄-SiH₃D chemical shift is estimated to be 0·0080 ± 0·0005 p.p.m., the SiH₄ resonance being to low field.