METALLOMETHANE. VII. 199Hg-NMR-STUDIEN AN MERCURIMETHANEN CH4-n(HgX)n (X = Cl, Br, I UND CN)

Article abstract of DOI:10.1016/S0022-328X(00)98545-0

199Hg NMR spectra of the partly newly prepared mercurimethanes CH4-n(HgX)n (1<*>n<*>4; X=Cl, Br, I and CN) have been measured.The chemical shifts δ(199Hg) indicate increasing deshielding of the mercury nuclei with increasing n and in the series I < Br < Cl < CN.The effects in the shifts are assigned to changes in the paramagnetic contributions to shielding.The influences of different ligands X on δ(199Hg) with a fixed n are explained by changes in population and extension of the 6p orbitals of mercury.The variations of δ(199Hg) with n correlate with the course of excitation energies ΔE.The coupling constants 2J(199Hg-1H) decrease with growing trans influence of the ligands X.