Cyclic voltammetry experiments were conducted under N2 at 295 ± 3 K using a standard three-electrode setup consisting of a glassy carbon working electrode, a platinum counter electrode and the Ag/AgCl reference electrode, and with 0.10 M Bu4NPF6 as the supporting electrolyte. The reduction potentials were recorded at a scan rate of 100 mV s -1 and reported with reference to the ferrocene/ferrocenium (Fc/Fc+) redox couple. The working electrode was polished with 0.25 μm diamond polishing paste and lapping oil in the glove box and thoroughly rinsed with the solvent used in the experiment. A Gamry Reference 1010B potentiostat and Gamry software were used for data collection and analysis. ) . 1,2-Bis(4-bromophenyl)ethyne (3.40 g, 10.0 mmol) and decaborane (1.45 g, 11.5 mmol) were dissolved in anhydrous toluene (100 mL) at room temperature under nitrogen atmosphere. N,N-dimethylaniline (2.28 mL, 18.0 mmol) was added to the reaction mixture, and the mixture was stirred at 120 °C for 24 h. After cooling down, the mixture was decanted from the solid residue and evaporated to dryness. The crude mixture was purified by silica gel column chromatography (n-hexane/CH2Cl2 = 20/1). Recrystallization from chloroform/methanol (10/1) afforded 5 as a colorless crystal (2.73 g, 60%