Low-Coordinate Magnesium Sulfide and Selenide Complexes.

The reactions of [{( iPrDip NacNac)Mg} 2 ] 1 ( iPrDip nacnac = HC(iPrCNDip) 2 ) with Ph 3 P═O at 100 °C afforded the phosphinate complex [( iPrDip NacNac)Mg(OPPh 3 )(OPPh 2 )] 3 . Reactions of 1 with Ph 3 P═E (E = S, Se) proceeded rapidly at room temperature to low-coordinate chalcogenide complexes [{( iPrDip NacNac)Mg} 2 (μ-S)] 4 and [{( iPrDip NacNac)Mg} 2 (μ-Se)] 5 , respectively. Similarly, reactions of R NHC═S ((MeCNR) 2 C═S with R = Me, Et, or i Pr) with 1 afforded NHC adducts of magnesium sulfide complexes, [{( iPrDip NacNac)Mg( R NHC)}(μ-S){Mg( iPrDip NacNac)}] 6 , that could alternatively be obtained by adding the appropriate R NHC to sulfide complex 4 . Complex 4 reacted with 1-adamantylazide (AdN 3 ) to give [{( iPrDip NacNac)Mg} 2 (μ-SN 3 Ad)] 7 and can form various simple donor adducts in solution, of which [( iPrDip NacNac)Mg(OAd)} 2 (μ-S)] 8a (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.