Low-Coordinate Magnesium Sulfide and Selenide Complexes.

The reactions of [{(NacNac)Mg}] (nacnac = HC(iPrCNDip)) with PhP═O at 100 °C afforded the phosphinate complex [(NacNac)Mg(OPPh)(OPPh)] . Reactions of with PhP═E (E = S, Se) proceeded rapidly at room temperature to low-coordinate chalcogenide complexes [{(NacNac)Mg}(μ-S)] and [{(NacNac)Mg}(μ-Se)] , respectively. Similarly, reactions of NHC═S ((MeCNR)C═S with R = Me, Et, or Pr) with afforded NHC adducts of magnesium sulfide complexes, [{(NacNac)Mg(NHC)}(μ-S){Mg(NacNac)}] , that could alternatively be obtained by adding the appropriate NHC to sulfide complex . Complex reacted with 1-adamantylazide (AdN) to give [{(NacNac)Mg}(μ-SNAd)] and can form various simple donor adducts in solution, of which [(NacNac)Mg(OAd)}(μ-S)] (OAd = 2-adamantanone) was structurally characterized. The nature of the ionic Mg-E-Mg unit is described by solution and solid-state studies of the complexes and by DFT computational investigations.