Nuclear Spin—Spin Coupling Involving Heavy Nuclei. The Coupling between Hg199 and H1 Nuclei in CH3HgX and CH3CH2HgX Compounds

Abstract

Nuclear spin coupling between protons and Hg199 nuclei in CH3HgX and CH3CH2HgX compounds has been investigated. As the X substituent is made more electronegative very large increases in the spin-coupling constant up to 2½-fold were observed. Smaller alterations occur in different solvent media, and alkyl exchange could be observed in several compounds. In the CH3CH2HgX compounds the changes in the spin-coupling constants of the Hg nucleus with the protons in the methylene group and in the methyl group are comparable in magnitude. The results are interpreted in terms of a simplified model for contact interaction employing optical hyperfine structure (hfs) constants. Qualitative arguments are employed to assess the relative importance of other coupling mechanisms. It is concluded that spin coupling arising from electron orbital motion is negligible, and while dipole—dipole contributions may be important, the evidence indicates the Fermi contact interaction is the dominant coupling mechanism.

Therα-structure and anisotropy of the Hg-C indirect coupling constant of methylmercury nitrate dissolved in nematic and lyotropic liquid crystals

“…This is probably also the situation in ZLI 1167, which is a mixture of three cyclohexane derivatives. The similar JHg~ values (--240.6 Hz in benzene [19] and -242.5 Hz in ZLI 1167) support this idea. In the lyotropic phase which contains about 50 per cent D20 , the molecules are at least partially dissociated.…”

Proton magnetic resonance and Raman spectroscopic studies of methylmercury (II) complexes of inorganic anions

“…The coupling constant of CH3HgSCN has been previously measured in pyridine (208.0 Hz) (34) and methanol (205.6 Hz) (35) solution.…”

Solvent, concentration, and temperature dependance of the platinum–phosphorus nuclear magnetic résonance coupling constants in cis- and trans-[PtCl2(PBu3n)2]

“…However, there seem to be no studies on coordination complexes with the exception of a small amount of data (published subsequent to the completion of our studies) on lJptVp in cis-[ P~C I~( P B U~~)~] and tran~-[PtI2(PBu"3)~] (5). Indeed the only extensive data on metal containing complexes of any type relates to 'JMK couplings in tin, lead, mercury, and thallium alkyls (6)(7)(8)(9). The introduction of fast Fourier transform techniques has made 31P nmr spectroscopy a tool of' increasing importance for the characterisation of co-ordination complexes containing tertiary phosphine ligands and it has also found exten1Author to whom correspondence should be addressed.…”