Triethylamine

NaOH and NH₄PF₆ were purchased from Fujifilm Wako Chemicals Co. HCl and Na₂WO₄·2H₂O were obtained from Kanto Chemical Co. 2,2,6,6-Tetramethyl-4-piperidyl methacrylate, 3-[[2-(methacryloyloxy)ethyl]dimethylammonio]propane-1-sulfonate, thioglycolic acid, 4,4′-azobis(4-cyanovaleric acid), hydrogen peroxide, ethylviologen dibromide, 4,4′-bipyridyl, indomethane, 2-bromoethanol, methacryloyl chloride, triethylamine, hydroquinone and tetrabuthylammonium chloride were purchased from Tokyo Chemical Industry Co. Other chemicals were obtained from the above companies. All compounds were used as received. The anion-exchange membrane was obtained from Takahata precision Co. The membrane originally had methanesulfonate anions. Chloride polymers were obtained after immersing them in 1 M NaCl aqueous solution at 80 °C for 2 days. For control experiments, Nafion perfluorinated membrane (product number: 676470, thickness 0.002 inch) was purchased from Sigma-Aldrich Co., and SELEMION (anion-exchange membrane, product name: AMVN, chloride anions) was obtained from AGC Engineering Co. Nafion was immersed in 0.1 M NaOH aqueous solution overnight for neutralization.

1-Nitroso-2-naphthol, zinc chloride, (2-bromoethyl)benzene, 2,3,3-trimethylindolenine,
and triethylamine were purchased from Tokyo Chemical Industry (TCI).
Tetrahydrofuran, acetonitrile, dichloromethane, and ethanol were obtained
from Honeywell Burdick & Jackson (B&J). Metal ions including
Na⁺, K⁺, Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Sn²⁺, Pb²⁺, Cr³⁺, Mn²⁺, Fe²⁺, Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, and Hg²⁺ were obtained from Sigma-Aldrich as
chloride salts. All reagents were of analytical grade and used as
received unless stated otherwise. Deionized water (DI) was used for
all experiments. Analytical thin-layer chromatography (TLC) was performed
on Kieselgel F₂₅₄ pre-coated aluminum TLC plates obtained
from EM Science. Visualization was performed with a 254 nm ultraviolet
lamp. Column chromatography was carried out with Merck silica gel
60 (230–400 mesh ASTM). UV/vis absorption spectra were measured
on a Shimadzu (UV-1800) spectrophotometer at ambient temperature.
The path length of a quartz cell was 1 cm. ¹H NMR (500
MHz) and ¹³C NMR (125 MHz) spectra with entire proton decoupling
were recorded on a Bruker AVANCE 500 NMR spectrometer, and chemical
shifts in ppm were quoted relative to the residual signals of deuterated
solvents. High-resolution mass spectra were recorded using a Bruker
micrOTOF mass spectrometer (ESI-TOF) and reported with ion mass/charge
(m/z) ratios as values in atomic mass units.