New Polyether Complexes of Germanium(II) and Tin(II): Synthesis, Structural Characterization and Reactivit

The chemistry involving group 14 cations and polyether ligands has been an area of great interest in the last decade. The Macdonald Group has long been interested in the synthesis, characterization and reactivity of polyether complexes containing group 13 and 14 elements in low oxidation state. Recently, our group has demonstrated that the properties of crown ethers and of the more flexible glyme ligands make them ideal for the stabilization of group 14 elements in the +2 oxidation state. Many of the resulting polyether complexes hold great potential for further reactivity in that they may act as Lewis acids to simple nucleophiles like water and ammonia while retaining a non-bonding electron pair.;A series of complexes of crown ethers and glymes with Ge(II) and Sn(II) bromide have been synthesized. Specifically, [GeBr([15]crown-5)][GeBr 3], [GeBr([18]crown 6)][GeBr3], [GeBr(triglyme)][GeBr 3], [GeBr(tetraglyme)][GeBr3], [SnBr([18]crown-6)][SnBr 3], [Sn([15]crown-5)2][SnBr3]2, [SnBr(triglyme)][SnBr 3] and [SnBr(tetraglyme)][SnBr3] have been fully characterized including by single crystal X-ray diffraction. [GeBr(triglyme)][GeBr 3] and [GeBr(tetraglyme)][GeBr3] represent the first examples of crystallographically confirmed glyme complexes of germanium. The synthesis of [GeBr(dibenzo[24]crown-8)][GeBr3] and [GeCl(dibenzo[24]crown-8)][GeCl 3] are also reported, along with the crystal structure of the latter's water adduct, which features the water molecule adjacent to the GeCl + ion within the cavity of the crown ether. Recrystallization of the salt [SnOTf(dibenzo[24]crown-8)][OTf] generated crystals of the water complex suitable for examination by single crystal X-ray diffraction.