Reversible Binding of Ethylene and Propylene by Germylenes

The diarylgermylenes Ge­(ArMe6)2 and Ge­(AriPr4)2 (ArMe6 = C6H3-2,6-(C6H3-2,4,6-Me3)2), AriPr4 = C6H3-2,6-(C6H3-2,6-iPr2)2) are shown to react reversibly with ethylene. It is demonstrated that the more sterically crowded Ge­(AriPr4)2 also reversibly binds propylene. The germirane products Ar2GeCH2CHR (Ar, R = ArMe6, H (1a), AriPr4, H (1b), and AriPr4, Me (1c)) were characterized via 1H and 13C NMR spectroscopy and by X-ray crystallography in the case of 1b. Thermolysis of Ge­(AriPr4)2 under ethylene resulted in Ge–C bond homolysis and the formation of the digermene [(AriPr4)­Ge­(Et)]2 (1d). The thermodynamic parameters of the reactions were determined by variable-temperature 1H NMR spectroscopy