Interstate Crossing-Induced Chemiexcitation Mechanism as the Basis for Imidazopyrazinone Bioluminescence

• Type: Article in International Scientific Journal
• Date: 2016

Authors

da Silva, LP (Author) FCUP; Magalhaes, CM (Author) Other; Joaquim C G E Esteves da Silva (Author) FCUP

Journal

Title: ChemistrySelect

Vol. 1

Pages: 3343-3356

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 21 Citations

Scopus - 25 Citations

Other information

Authenticus ID: P-00M-ND4

DOI: 10.1002/slct.201600688

Abstract (EN): Imidazopyrazinone dioxetanone is a central molecule in bioluminescence, as it is the scaffold responsible for light emission in many marine species. Herein, we have theoretically studied the thermolysis of its neutral and anionic forms. Our results allowed us to explain imidazopyrazinone bioluminescence with the Interstate Crossing-Induced Chemiexcitation (ICIC) mechanism, and explain why neutral forms emit light efficiently to the contrary of anionic ones. Both forms decompose via a step-wise-biradical pathway, but the biradical is formed either via an electron transfer (anion) or due to homolytic bond cleavage (neutral species). Absence of electron transfer leads to an entropic trap, a flat region where infinite possibilities for chemiexcitation exist. However, the resulting products can be in either triplet or singlet excited states. The triplet to singlet ratio is determined by the electron spin density distribution, which controls the rates of intersystem crossing.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 14