Preparation, spectroscopic properties and thermal stabilities of organomercury compounds containing the bulky ligand (Me(3)Si)(3)C or (PhMe(2)Si)(3)C

Mercury compounds of the types HgR(1)R (R(1) = C(SiMe(3))(3); R = Me, Pr-i, Bu, (t)Bu or Ph) and HgR(2)R (R(2) = C(SiMe(2)Ph)(3); R = Me, Bu, CH(2)Ph or Ph) have been prepared. Those containing R(1) were made by reactions of the bromides HgR(1)Br with the Grignard reagents MgRX, and those containing R(2) by reaction of HgR(2)Cl with LiR or, for R = CH(2)Ph, with Mg(CH(2)Ph)Cl. Replacement of one R group in HgR(2) by the bulky R(1) or R(2) group leads to a large increase in thermal stability, a marked shift in the Hg-199 resonance to lower frequency and an increase in the coupling constant (1)J(C-13-Hg-199) for the Hg-R bond. The compound HgR(2)Cl does not react further with LiR(2) in tetrahydrofuran, but with LiR(1) gives HgR(1)R(2); the arrangement of the SiMe(2)Ph groups in the latter in solution in CH2Cl2 at low temperature appears to be different from that in the solid.