5 formyl 2 thienylboronic acid

2,4-Dimethylpyrrole
(≥ 97.0, Sigma-Aldrich), 4-bromobenzaldehyde (≥ 99.0,
Sigma-Aldrich), trifluoroacetic acid (≥ 99.0, Sigma-Aldrich),
DDQ (≥ 98.0, Sigma-Aldrich), boron trifluoride diethyl etherate
(≥ 98.0, TCI), 5-formyl-2-thienylboronic acid (≥ 95.0,
Sigma-Aldrich), bis(triphenylphosphine)palladium(II) dichloride (≥
98.0, Sigma-Aldrich), n-hexane (HPLC grade, ≥ 99.0, Sigma-Aldrich),
dichloromethane (anhydrous, ≥ 99.9, Sigma-Aldrich), acetonitrile
(anhydrous, ≥ 99.9, Sigma-Aldrich), ethanol (≥ 99.8,
Sigma-Aldrich), chloroform (≥ 99.8, Sigma-Aldrich), and ethyl
acetate (anhydrous, ≥ 99.8, Sigma-Aldrich) were used. All metal
salts were used as their water-soluble sulfate, nitrate, or chloride
salts, purchased from Sigma-Aldrich (≥ 95). A Varian VNMRJ
600 nuclear magnetic resonance spectrometer was used for ¹H NMR and ¹³C NMR measurements. Mass analysis was conducted
with a Thermo Q-Exactive Orbitrap device. Ultraviolet–visible
(UV–vis) absorption spectra were obtained with a spectrophotometer
(Shimadzu 1900i). Fluorescence emission measurements were obtained
using a Varian Cary Eclipse fluorescence spectrophotometer. Quantum
yield measurements were conducted with a Hamamatsu Quantaurus-QY absolute
PL quantum yield spectrometer.