series of bis(i;6-hexamethylbenzene)(η6,η6-[2,l]cyclophane)diruthenium(II, II) tetrakis(tetrafluoroborate) complexes, 4, 5, 9, 10, and 11, has been prepared, where the [2n] cyclophanes are (l,4)cyclophane, (l,3)cyclophane, 4,7,13,16-tetramethyl-(1,4)cyclophane, 4,5,7,8-tetramethyl-(l,4)cyclophane, and (l,3,5)cyclophane, respectively. These 4+ diruthenium complexes undergo two-electron reduction to give 7, 8,12,13, and 14, respectively, in which each of the cyclophane ligands now has two cyclohexadienyl anion decks connected by a new carbon-carbon bond. The assignment of structures to these two-electron reduction products is based on 1H and 13C NMR spectralanalyses, electrochemical studies, and X-rayphotoelectron data. A single-crystal X-ray analysis confirmed the structure assigned to the (l,4)cyclophane derivative 7 and showed that the carbon-carbon bond connecting the two cyclohexadienyl anion decks in 7 is 1.96 (3) Å in length, an extremely long carbon-carbon bond. A theoretical analysis of these 2+ diruthenium complexes and their formation is presented.
ASJC Scopus subject areas
- Colloid and Surface Chemistry