Scientific. Ethyl p-toluenesulfonate (98%) was from
Sigma-Aldrich. The n-octyl p-toluenesulfonate
and methyl-tri-n-octylammonium chloride (>95%) were from TCI America.
MnCl2·4H2O (99.7%) was supplied by J. T.
Baker, FeCl2 (98%) was from Sigma-Aldrich, and NH4PF6 (99.99%) was from GFS chemicals. Anhydrous diethyl
ether and acetone were from EMD chemicals, while dichloromethane,
chloroform, acetonitrile, EDTA, and KNO3 were purchased
from Mallinckrodt. Anhydrous N,N-dimethylformamide
(DMF) of 99.8% purity (kept over 4-Å molecular sieves) and plastic-backed
silica gel TLC plates (Z122777-25EA) were from Sigma-Aldrich. Xanthine,
equine ferricytochrome c (lot 7752), and (+)-sodium
was prepared by R. Wiley.1 (link) Triethylamine
(Et3N) of >99.5% purity was obtained from Thermo Scientific
Pierce. All chemicals were used as received without further purification.
The 1H NMR spectra were recorded on a spectrometer “Mercury
Varian 300” with deuterated chloroform as solvent.