Figure 2.

Examination of the platinum-catalyzed bioorthogonal cleavage reaction. a. Naphthalimide-based fluorogenic probes were used to study the cleavage efficiency of the platinum reaction for decaging alkyne-containing molecules. The caged naphthalimide derivatives exhibited high stability in solution and cell media and their quenched fluorescence could be reactivated upon removal of the caging group (λ_ex = 445 nm, λ_em = 545 nm). b. Changes in fluorescence intensity during the time course of the decaging reaction between fluorogenic probe 7 and platinum salts (K₂PtCl₄/CisPt). c. Determined half-time for the reaction of 7 with activated and nonactivated platinum salts. d. Decaging kinetics for the pentynoyl amide fluorophore. Rate constants were determined under pseudo first order conditions with a 50 μM final concentration of probe 7 and 10–50 equiv of aqua platinum metals. e. Kinetics profiles of the decaging reaction in the presence of the metal poisons CS₂ and EDTA. Error bars represent ± s.d. (n = 3). All experiments were repeated 3 independent times. f. Calculated mechanism for the depropargylation reaction catalyzed by Pt with model substrate 4a. Calculations were performed with an implicit solvent model for water. Geometries and frequencies were calculated with the functional revPBE and, to obtain very accurate energetics, single point energy calculations with DLPNO–CCSD(T) and counterpoise corrections were employed to suppress basis set superposition errors.