Antioxidative Reactivity of L-Ascorbic Acid and D-Isoascorbic Acid Species towards Reduction of Hexachloroiridate (IV)

Table 1

Observed second-order rate constants for the reduction of [IrCl₆]^2– by AA and IAA at 25.0°C and 1.0 M ionic strength.

Reductant	pH	k′/M^−1s^−1
AA	0.16	(7.6 ± 0.1) × 10^3
	0.26	(9.6 ± 0.2) × 10^3
	0.41	(1.66 ± 0.02) × 10^4
	0.63	(2.42 ± 0.04) × 10^4
	0.81	(3.01 ± 0.06) × 10^4
	1.11	(5.49 ± 0.09) × 10^4
	1.41	(1.29 ± 0.03) × 10^5
	1.63	(2.19 ± 0.05) × 10^5
	1.81	(3.75 ± 0.09) × 10^5
	2.11	(6.8 ± 0.2) × 10^5
	2.33	(1.15 ± 0.06) × 10^6
IAA	0.16	(7.5 ± 0.1) × 10^3
	0.26	(8.3 ± 0.2) × 10^3
	0.41	(1.40 ± 0.02) × 10^4
	0.63	(2.04 ± 0.04) × 10^4
	0.81	(2.78 ± 0.06) × 10^4
	1.11	(4.78 ± 0.08) × 10^4
	1.41	(9.4 ± 0.03) × 10^4
	1.63	(1.97 ± 0.04) × 10^5
	1.81	(3.10 ± 0.07) × 10^5
	2.11	(6.1 ± 0.1) × 10^5
	2.33	(1.00 ± 0.02) × 10^6