Persistent Digermenes with Acyl and α-Chlorosilyl Functionalities.

We report the preparation of α-chlorosilyl- and acyl-substituted digermenes. Unlike the corresponding transient disilenes, these species with a Ge=Ge double bond show an unexpectedly low tendency for cyclization, but in turn are prone to thermal Ge=Ge bond cleavage. Triphenylsilyldigermene has been isolated as a crystalline model compound, and is the first fully characterized example of a neutral digermene with an A2 GeGeAB substitution pattern. Spectroscopic and computational evidence prove the constitution of 1-adamantoyldigermene as a first persistent species with a heavy double bond conjugated with a carbonyl moiety.