Fig. 2: Mechanistic insights into the PDC reaction.
From: Site-selective photocatalytic functionalization of peptides and proteins at selenocysteine
A Proposed mechanism for the PDC reaction that converts diselenides to selenoethers. B Normalized photoluminescence (PL) counts of photocatalyst [Ir(dF(CF3)ppy)2(dtbpy)] (5) (c = 2.5 μM and 10 μM) in argon-sparged 1:1 v/v H2O:MeCN over a period of 3 μs monitored at 470 nm (excitation wavelength 415 nm) with or without PTA (4) (0 mM and 10 mM). C Changes in the PL intensity of 5-carboxytetramethylrhodamine (TAMRA)-derivatized selenocystamine (15) in the presence of [Ir(dF(CF3)ppy)2(dtbpy)] (5) and PTA (4) monitored at 615 nm (excitation wavelength 550 nm). D Top: B3PW91-GD3(BJ)/6-311 + G(2df,p)//B3PW91-GD3(BJ)/6-31 + G(d,p) computed Gibbs free energy profile in kcal/mol (SMD MeCN solvent, 298.15 K) including main and competitive pathways for [N-Boc-l-Sec-OtBu]2; bottom: sensitivity of activation barriers for heterolytic deselenization to steric effects. PTA = 1,3,5-triaza-7-phosphaadamantane, Arb. Units arbitrary units, SET single electron transfer.
