New compounds with Ge/Ge and Ge/C multiple bonds

Treatment of GeCl2 · dioxane with the Grignard reagent RMgBr (R = 2,5-tBu2C6H3) furnishes the tetraaryldigermene R2GeGeR2 (4). The X-ray structure analysis of 4 reveals a long GeGe double bond of 236.4 pm and the largest trans-bending angles of the substituents (42.6° and 37.2°) observed so far. The reaction of hexa-2,4-diyne with the germylene R2Ge: (R = 2-tBu-4,5,6-Me3C6H) yields red crystals of the acetylene-bridged bis(germaethene) (Me)R2GeC–CC–CGeR2(Me) 7, the red colour of which indicates conjugation between the two double bonds.

The reaction of the Grignard compound RMgBr, R = 2,5-tBu2C6H3, with GeCl2 · dioxane furnishes the digermene 4 with a long GeGe double bond length and the largest trans-bent angles observed so far for digermenes. In solution, the digermene R2GeGeR2, R = 2-tBu-4,5,6-Me3C6H dissociates into two molecules of the germylene R2Ge: which react with hexa-2,4-diyne to give the acetylene-linked bis(germaethene) 7.Figure optionsDownload as PowerPoint slide