A Tetrairon Dication Featuring Tetraethynylbenzene Bridging Ligand: A Molecular Prototype of Quantum Dot Cellular Automata

The unprecedented tetrairon dication [{Cp*(dppe)FeC≡C‐} 4 ‐μ‐(1,2,4,5‐C 6 H 2 )](PF 6 ) 2 ( 1 ) was obtained through a sequence of three reactions from 1,2,4,5‐tetraethynylbenzene, Cp*(dppe)FeCl (Cp*=C 5 Me 5 , dppe=1,2‐bis(diphenylphosphino)‐ethane), KO t Bu, and ferrocenium hexafluorophosphate. The cyclic voltammogram of the target molecule, isolated in 77 % yield, exhibits four well separated and reversible redox events showing that 1 is thermodynamically stable with respect to disproportionation ( K c>10 6 ). The tetranuclear dication 1 was characterized by XRD on single crystal, IR and NMR spectroscopies and Mössbauer spectrometry. The experimental data show that 1 behaves as a class II mixed‐valence complex with the positive charges preferentially disposed on antipodal positions. This new molecule can be regarded as a potential molecular prototype of quantum dot cellular automata.