Aktuelle Meldungen AG Winter

Daniel's Organometallics Cover - Same but Different

The electronic properties of two structural isomers of macrocyclic tetraruthenium complexes are compared. They are constructed either from 2,5-divinylthiophene and thiophene-2,5-dicarboxylate as two pairs of different types of linkers (macrocycle 2-S) or from 5-vinyl-thiophene-5-carboxylate as one type of linker (macrocycle 2-A). Detailed electrochemical and spectroelectrochemical experiments were conducted to monitor the changes of the Ru-CO stretching vibrations in the IR and the electronic transitions in the visible and near infrared. These experiments revealed that the mixed-valent oxidized forms of 2-S feature two charge delocalized diruthenium divinylthiophene entities, which are mutually insulated by the dicarboxylate linkers. In mixed-valent 2-Aⁿ⁺, however, all vinylruthenium carboxylate units are electronically coupled such that the oxidized macrocycle resembles a molecular electronically conductive loop. The cover artwork depicts the schematic structures of macrocycles 2-A and 2-S, the carbonyl bands in their neutral, dicationic, and tetracationic states, and computed charge density differences for the low-energy electronic transitions of the dications. See the paper by Winter and co-workers here.