Combined Experimental and Theoretical Investigation into the Photophysical Properties of Halogenated Coelenteramide Analogs

• Type: Article in International Scientific Journal
• Date: 2022

Authors

Afonso, ACP (Author) Other; Gonzalez-Berdullas, P (Author) Other; Joaquim C G E Esteves da Silva (Author) FCUP; da Silva, LP (Author) FCUP

Journal

Title: Molecules

Serial No. 9 Vol. 23 No. 2288

Final page: 8875

ISSN: 1420-3049

Publisher: MDPI

Indexing

ISI Web of Knowledge - 1 Citation

Associated Projects

ChemiTumorTher - Quimioluminescência Marinha como uma Terapia Anticancro de Amplo Espectro com uma Selectividade e Actividade Tumoral Melhorada

Other information

Authenticus ID: P-00X-KFP

DOI: 10.3390/molecules27248875

Abstract (EN): Marine Coelenterazine is one of the most well-known chemi-/bioluminescent systems, and in which reaction the chemi-/bioluminophore (Coelenteramide) is generated and chemiexcited to singlet excited states (leading to light emission). Recent studies have shown that the bromination of compounds associated with the marine Coelenterazine system can provide them with new properties, such as anticancer activity and enhanced emission. Given this, our objective is to characterize the photophysical properties of a previously reported brominated Coelenteramide analog, by employing a combined experimental and theoretical approach. To better analyze the potential halogen effect, we have also synthesized and characterized, for the first time, two new fluorinated and chlorinated Coelenteramide analogs. These compounds show similar emission spectra in aqueous solution, but with different fluorescence quantum yields, in a trend that can be correlated with the heavy-atom effect (F > Cl > Br). A blue shift in emission in other solvents is also verified with the F-Cl-Br trend. More relevantly, the fluorescence quantum yield of the brominated analog is particularly sensitive to changes in solvent, which indicates that this compound has potential use as a microenvironment fluorescence probe. Theoretical calculations indicate that the observed excited state transitions result from local excitations involving the pyrazine ring. The obtained information should be useful for the further exploration of halogenated Coelenteramides and their luminescent properties.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 11