Solvent effect on the Spectra of Methylene Green and Methylene Blue

A Plant Dye for Photocatalytic Methane Conversion

“…The amount of product was quantified by proton nuclear magnetic resonance ( 1 H NMR) spectroscopy in the liquid phase (Figures S4-S9) and gas chromatography (GC) in the gas phase (Figures S10 and S11). We achieved an 8 % conversion of 13 CH 4 with almost 96 % selectivity of 13 CH 3 TFA (86 %) and 13 CH 2 (TFA) 2 (10 %) after 18 h (Figures 1b,c, and S12).…”

“…to CH 4 ), 30 μL of trifluoroacetic anhydride (TFAA), and 0.6 mL of trifluoroacetic acid (TFA), and sonicated the mixture for 5 min until the reagents were completely dissolved (Figure S1). Next, we filled the tube with a gas mixture of 13 CH 4 /O 2 /He = 5 : 18 : 2, where 13 CH 4 was used to avoid misinterpretation of the catalysis results due to interference from other carbon sources. The tube was placed on a magnetic stirring apparatus with a 420 nm LED and heated to 80 °C.…”

“…[12] Moreover, their high-energy singlet excited state has a very short lifetime (~ns), which hinders their encounter with CH 4 for efficient reaction. [13] In this study, we discovered that alizarin, an anthraquinone derivative extracted from madder, [14] can be bridged by chloride (Cl À ) and proton to form ground state dimer in an acidic medium, making it an effective photocatalyst. The rapid intracomplex electron transfer likely produces an oxidized alizarin radical (AQ + * ), which acts as a hydrogen atom transfer (HAT) reagent, breaking the methane CÀ H bond.…”