Synthesis of a Large Organometallic Macrocycle Comprising Four Ga−Ga Bonds and Four Bridging Ferrocene Dicarboxylato Ligands

The reaction of tetrakis[bis(trimethylsilyl)methyl]digallane(4), 1, with 1,1‘-ferrocenedicarboxylic acid afforded orange-red crystals of the macrocyclic compound 2 in a yield of 84%. 2 contains a large 32-atom heterocycle, which comprises four Ga−Ga single bonds bridged by four 1,1‘-ferrocenedicarboxylato ligands. The largest diameter of the molecule is about 2.5 nm. The redox-active Ga−Ga sites and ferrocene iron centers are all oxidized irreversibly within a narrow potential range.