Investigation of methylmercury derivatives of carboranes by the PMR method

1. In an investigation of the PMR spectra of methylmercury derivatives of ortho-, meta-, and paracarboranes, substantial variations of the spin-spin interaction constants JHg199-C-H1 were found as a function of the structure of the compound and the nature of the medium. 2. The values of JHg199-C-Hg1 in substituted ortho-carboranes\(\begin{array}{*{20}c} {R - C - C - HgCH_3 } \\ {\begin{array}{*{20}c} \backslash & / \\ \end{array} } \\ {B_{10} H_{10} } \\ \end{array}\) are satisfactorily correlated with the induction constants of the substituents R. 3. The sensitivity of the indicator group HgCH3 to the polar influence of substituted ortho-carboranes depends on the solvent, decreasing in the series CH2Cl2>dioxane>pyridine >dimethyl sulfoxide. 4. The presence of intramolecular coordination of certain substituents (R=C6H5CH2, CH3OCH2) with the metal atom of the indicator group HgCH3 was ascertained in substituted ortho-carboranes. 5. The sequence of increasing electronegativity of certain carboranyl radicals was established: $$\begin{array}{*{20}c} {o - HCB_{10} H_{10} C - CH_2< p - HCB_{10} H_{10} C -< m - HCB_{10} H_{10} C - } \\ {< m - PB_{10} H_{10} C -< o - HCB_{10} H_{10} C -< o - CH_3 - C(3 - F)B_{10} H_9 C -< o - CH_3 - C(9,12 - Cl_2 )B_{10} H_8 C - .} \\ \end{array}$$ 6. The dependence of the electron donor properties of the CH3Hg group on the selection of the solvent was demonstrated.