The role of CO₂ detachment in fungal bioluminescence: thermally vs. excited state induced pathways

Abstract

The fungal emission mechanism elucidated by computational chemistry: thermal CO2 release followed by peroxide breaking and excited state population.

Chemistry in Fungal Bioluminescence: A Theoretical Study from Luciferin to Light Emission

“…After vertical emission occurs, the geometry will change from E - V­(3) * to a more stable conformer, E - V­(3) , along the S 0 PES. The recent study in vacuum proposed two kinds of chemiexcitation mechanisms, which correspond to the different orders of CO 2 departure and O–O dissociation. This paper indicates that the two processes occur synergistically.…”

Elucidating the chemiexcitation of dioxetanones by replacing the peroxide bond with S–S, N–N and C–C bonds

“…[15][16][17] Generally, CL and BL occur via a two-step process: oxidation of the reactant toward the generation of an unstable and energyrich peroxide intermediate; and subsequent thermolysis of the peroxide intermediate, which allows for the thermally-activated singlet ground state (S0) reaction to produce an oxidized reaction product in the first singlet excited state (S1), leading to singlet chemiexcitation. [18][19][20][21][22] Chemiexcitation can also lead to the generation of chemiluminophores in their first triplet excited state (T1). [1][2][3]17 However, as phosphorescence is easily quenched in solution, peroxide-based CL and BL result from S1 chemiluminophores.…”

Bioluminescence – The Vibrant Glow of Nature and its Chemical Mechanisms

“…[64] Additionally recent investigations also aim to provide a detailed analysis of the decomposition of the high-energy intermediate (HEI) through both thermally and excited state-induced pathways. [65] Understanding the structure of fungal oxyluciferin permits to manipulate the color of the bioluminescence reaction. This can be accomplished by synthetically varying the catechol residue of the molecule to carry either a stronger electron withdrawing or -donating residue.…”

“…A current quantum chemical study by the group of I. Navizet on the mechanism of fungal bioluminescence focused on examining the chemical properties and pH‐dependent emission of the light emitter in aqueous solutions [64] . Additionally recent investigations also aim to provide a detailed analysis of the decomposition of the high–energy intermediate (HEI) through both thermally and excited state–induced pathways [65] …”