Lead-207 shielding in organolead compounds

Abstract

¹ H-{²⁰⁷Pb}Double-resonance experiments have been used to determine lead chemical shifts in 33 organolead compounds under a variety of conditions. δ(²⁰⁷Pb) broadly parallels δ(¹¹⁹Sn) in similar species, but its sensitivity to changes in chemical environment is some three times greater. The chemical shifts appear to be dominated by the paramagnetic contribution to the shielding. Changes-in δ(²⁰⁷Pb) with concentration can be used to study revrsible equilibria between species with four- and five-co-ordinate lead, the latter generally having the more highly shielded ²⁰⁷Pb nucleus.