A Germacalicene: Synthesis, Structure, and Reactivity

The synthesis of the germacalicene 7 from the reaction of the dipotassium germole dianion K-2[6] with 1,2-bis-diisopropylamino-3-chlorocyclopropenyl perchlorate is reported. Based on the crystal structure analysis and the results of DFT calculations, the germacalicene 7 can be viewed as a cyclopropenium germacyclopentadienide ylide that is isoelectronic to alpha-cationic phosphanes. First reactivity studies revealed its nucleophilic character and resulted in the isolation of the air- and moisture-stable carbonyl iron complex 15 and the cationic silver complex 20. One-electron oxidation of the germacalicene 7 was achieved by its reaction with [Ph3C][B(C6F5)(4)] and the bis-cationic Ge-Ge-bonded dimer 22 was isolated.