Unraveling the decarboxylation dynamics of the fluorescein dianion with fragment action spectroscopy

Gibbard, J.A.; Verlet, J.R.R.

Abstract

The decarboxylation dynamics of the doubly deprotonated fluorescein dianion, Fl2−, are investigated by recording fragment action spectra for the anion, Fl−, and its decarboxylated analog, Fl–CO2−, using a new reflectron secondary mass spectrometer. The formation of the anion, Fl−, is directly investigated by photoelectron imaging. The Fl− and Fl–CO2− action spectra indicate that, for λ < 400 nm, one-photon dissociative photodetachment, i.e., simultaneous decarboxylation and electron loss, competes with photodetachment, whereas for λ > 400 nm, decarboxylation only proceeds following electron loss via a sequential two-photon process. The primary decarboxylation pathway is the ready loss of CO2 from the relatively short-lived intermediate excited state, Fl−[D1], which is formed by electron loss from the dianion via resonant tunneling through the repulsive Coloumb barrier associated with a high-lying excited dianion state, Fl2−[S2].

Citation

Gibbard, J., & Verlet, J. (2023). Unraveling the decarboxylation dynamics of the fluorescein dianion with fragment action spectroscopy. The Journal of Chemical Physics, 158(15), Article 154306. https://doi.org/10.1063/5.0144851

• Journal Article Type: Article
• Acceptance Date: Apr 6, 2023
• Online Publication Date: Apr 21, 2023
• Publication Date: Apr 21, 2023
• Deposit Date: Apr 26, 2023
• Publicly Available Date: Apr 26, 2023
• Journal: The Journal of Chemical Physics
• Print ISSN: 0021-9606
• Electronic ISSN: 1089-7690
• Publisher: American Institute of Physics
• Peer Reviewed: Peer Reviewed
• Volume: 158
• Issue: 15
• Article Number: 154306
• DOI: https://doi.org/10.1063/5.0144851