spectra were recorded on an HP 8453 spectrophotometer. 1H NMR spectra were recorded on 400 MHz Bruker Avance III HD spectrometer
equipped with a 5 mm BB/1H SmartProbe at 253 K in CDCl3 or CD2Cl2 and referenced to residual
CHCl3 at 7.26 ppm and CH2Cl2 at 5.31
ppm. Mass spectra were recorded on a Thermo Scientific LTQ Orbitrap
XL spectrometer with an ION-MAX electrospray ion source in positive
mode.
Cyclic voltammetry was carried out at 298 K with an EG&G
Model 263A potentiostat having a three-electrode system–a glassy
carbon working electrode, a platinum wire counterelectrode, and a
saturated calomel reference electrode (SCE). Anhydrous CH2Cl2 (Aldrich) was used as solvent and tetrakis(n-butyl)ammonium perchlorate, recrystallized twice from
absolute ethanol, and dried in a desiccator for at least 2 weeks,
was used as the supporting electrolyte. The reference electrode was
separated from the bulk solution using a fritted-glass bridge filled
with the solvent/supporting-electrolyte mixture. The electrolyte solution
was purged with argon for at least 2 min, and all measurements were
carried out under an argon blanket. All potentials were referenced
to the SCE. Elemental analyses were obtained from Atlantic Microlab,
Inc.