Table 1. Comparison of the H₂O₂ Formation Rates of Selected Acridine Derivatives in the Photochemical Oxidation of NADH^a.

catalyst	λmax/λex [nm]b	TF [h–1]c
acridine orange (R1 = CH3, R2 = H, X = N, Y = CH)	480/450	66 ± 3
proflavin (R1 = H, R2 = H, X = N, Y = CH)	445/450	207 ± 17
methylene blue (R1 = CH3, R2 = H, X = S+, Y = N)	664 and 613shoulder/662	95 ± 3
phenosafranine (R1 = H, R2 = H, R3 = phenyl, X = N+, Y = N)	522/512	99 ± 2
Safranine O (R1 = H, R2 = CH3, R3 = phenyl, X = N+, Y = N)	507/519	97 ± 3
FMN	450/450	154 ± 18

^aGeneral conditions: 50 μM catalysts, 50 mM KPi, pH 7.0, 1 mM NADH, 30 °C, 300 rpm.

^bλ_max = wavelength exhibiting the maximal photoabsortion; λ_ex = wavelength of the LED light source used for photoexcitation.

^cTF = turnover frequency of the catalyst = (H₂O₂ formation rate) [mM h^–1]/(concentration of the photocatalyst) [mM].