Calcium thiolates and selenolates: Synthesis and structures

The synthesis and structural characterization of a family of calcium thiola tes and selenolates is described. In the solid state the compounds adopt ei ther contact pairs, as observed in Ca(THF)(4)(SMes*)(2) (1), (Mes* 2,4,6-tB u(3)C(6)H(2)), and Ca(THF)(4)(SeMes*)(2), (2), or separated ions as shown i n [Ca(18-crown-6)(HMPA)(2)] [SeMes*](2) (3). The two different ion associat ion modes are induced by addition of specific donors. The compounds were pr epared by metalation involving the reaction of elemental calcium dissolved in dry liquid ammonia with either HSMes* or Mes*SeSeMes*. All compounds wer e characterized by X-ray crystallography, NMR and IR spectroscopy.