Reactivity of the tripodal trithiol 1,1,1-tris(mercaptomethyl)ethane toward methyl- and ethyl-mercury halides

Abstract

The reaction of the tripod-like trithiol MeC(CH₂SH)₃ with MeHgl or EtHgCl in organic solutions, in presence of a base such as pyridine or triethylamine, allows the isolation of the trimetallic derivatives MeC(CH₂SHgR)₃(R = Me or Et). An X-ray structure determination for the methylmercury complex has been carried out. Crystal data: monoclinic, space group P2₁/a, a= 11.892(9), b= 18.621(2), c= 13.932(2)Å, β= 90.95(3)° and Z= 8. The structure has been solved by three-dimensional Patterson and Fourier syntheses and refined by least squares to a conventional R value of 0.036. The complex can be essentially described as an aggregate of three, virtually independent, linear two-co-ordinated methylmercury thiolates. However ¹H and ¹³C-{¹H} NMR spectra have shown that the trend of the reaction of methylmercury iodide with the trithiol, in pyridine solution, is quite different from that of the corresponding reaction with a related monothiol such as propane-1-thiol. This discrepancy has been ascribed to the potential chelating ability of the tripodal thiol, which should allow the formation of intermediate chelated species, in which the metal atom has co-ordination numbers greater than two.