Synthesis of a Neutral Mixed-Valence Diferrocenyl Carborane for Molecular Quantum-Dot Cellular Automata Applications

The preparation of 7‐Fc+‐8‐Fc‐7,8‐nido‐[C2B9H10]− (Fc+FcC2B9−) demonstrates the successful incorporation of a carborane cage as an internal counteranion bridging between ferrocene and ferrocenium units. This neutral mixed‐valence FeII/FeIII complex overcomes the proximal electronic bias imposed by external counterions, a practical limitation in the use of molecular switches. A combination of UV/Vis‐NIR spectroscopic and TD‐DFT computational studies indicate that electron transfer within Fc+FcC2B9− is achieved through a bridge‐mediated mechanism. This electronic framework therefore provides the possibility of an all‐neutral null state, a key requirement for the implementation of quantum‐dot cellular automata (QCA) molecular computing. The adhesion, ordering, and characterization of Fc+FcC2B9− on Au(111) has been observed by scanning tunneling microscopy. Zwitterionische molekulare Schalter: Eine gemischtvalente Neutralverbindung wurde synthetisiert und charakterisiert. Spektroskopische Daten und TD‐DFT‐Rechnungen sprechen für einen über die Brückeneinheit vermittelten Ladungstransfer und für einen ladungsfreien Nullzustand, der für Anwendungen als molekularer QCA‐Schalter unentbehrlich ist.