Formation and Reaction Kinetics of Biradicals and Triplet States in a Series of Carboxylated 1,4,5,8-Naphthalene Diimides.

The singlet-state deactivation products in a series of alkyl carboxylate substituted 1,4,5,8-naphthalene diimide () compounds were characterized using fluorescence and phosphorescence spectroscopies, as well as nanosecond laser flash photolysis. The reactive intermediates were quantified as a function of the number of methylenes in the alkyl linker. Rate constants for photoinduced electron transfer (PET) to the singlet excited state of the varied from 1.

Enzyme Modification and Oxidative Cross-linking Using Carboxylate-, Phenol- and Catechol-Conjugated 1,8-Naphthalimides.

The ground- and excited-state interactions of β-alanine, tyrosine and l-dopa substituted 1,8 naphthalimides (NI-Ala, NI-Tyr and NI-Dopa) with lysozyme and mushroom tyrosinase were evaluated to understand the mechanism of oxidative modification. Photooxidative cross-linking of lysozyme was observed for all three conjugates. The yield was significantly reduced for NI-Tyr and NI-Dopa due to intramolecular electron transfer to the excited singlet state of the 1,8-naphthalimide.

Defining the conditional basis of silicon phthalocyanine near-IR ligand exchange.

Bond cleavage reactions initiated by long-wavelength light are needed to extend the scope of the caged-uncaged paradigm into complex physiological settings. Axially unsymmetrical silicon phthalocyanines (SiPcs) undergo efficient release of phenol ligands in a reaction contingent on three factors - near-IR light (690 nm), hypoxia, and a thiol reductant. These studies detail efforts to define the mechanistic basis for this unique conditionally-dependent bond cleavage reaction.