NMR investigation of tetraphenyl-, vinyltriphenyl-, azidotriphenyl- and dihalodiphenyl-derivatives of fourth main group elements

A detailed NMR investigation of four series of aromatic organometallic compounds is described. The compounds are mainly of the type Ph₃MX where M is a group IV element and X is a phenyl, vinyl or an azido group. The hydrogen resonance spectra of the phenyl groups were recorded at several radiofrequencies and could be analysed as strongly-coupled five spin systems using computer techniques. The significance of the resulting chemical shifts and coupling constants is discussed. An electronegativity order has been proposed using meta coupling constants. Hydrogen resonance of the vinyl groups and nitrogen resonance of the azido groups have also been obtained, analysed and discussed. An attempt to clarify the nature of bonding in the azides was abortive since ¹⁴N spectral lines from the two outer nitrogen nuclei of the azido group were too broad to detect. © 1972.