Synthesis and Structure of the Germylyne Complexestrans-[X(dppe)2W≡Ge(η1-Cp*)] (X=Cl, Br, I) and Comparison of the W≡E Bonds (E=C, Ge) by Density Functional Calculations

A short W−Ge triple bond and a η1-bound Cp* substituent are characteristic of the germylyne complexes 2⋅toluene that are obtained from the reaction of 1 with the germylene complexes [Cp*GeX] (W−Ge 2.302(1) Å for X=Cl). Density functional calculations show that there are significant electronic differences between germylyne and carbyne ligands. X=Cl, Br, I; PP=Ph2PCH2CH2PPh2; Cp*=C5Me5.