Catalytic C−C/C−H Bond Activation Relay for Synthesis of Fluorescent Naphthoquinolizinium Salts

0571311 - ÚOCHB 2024 RIV DE eng J - Journal Article
Ulč, J. - Jacko, J. - Císařová, I. - Pospíšil, Lubomír - Nečas, D. - Kotora, M.
Catalytic C−C/C−H Bond Activation Relay for Synthesis of Fluorescent Naphthoquinolizinium Salts.
European Journal of Organic Chemistry. Roč. 26, č. 18 (2023), č. článku e202300153. ISSN 1434-193X. E-ISSN 1099-0690
Institutional support: RVO:61388963
Keywords : catalysis * C−C activation * C−H activation * fluorescence * heterocycles
OECD category: Organic chemistry
Impact factor: 2.8, year: 2022
Method of publishing: Open access
https://doi.org/10.1002/ejoc.202300153

Herein, we report the design and synthesis of a series of novel cationic nitrogen-embedded polyaromatic hydrocarbons with a planar geometry. The synthetic pathway is based on catalytic C−C/C−H bond activation relay that enabled preparation of regioselectively 5,6,10,11-tetrasubstituted naphtho[2,1,8-ija]quinolizinium salts bearing various types of substituents. Single-crystal X-ray analyses of selected compounds confirmed planarity of the quinolizinium core. Most of the prepared compounds exhibited strong fluorescence (Φs up to >99 %) ranging from 420–600 nm depending on the substitution pattern. According to DFT calculations LUMO is always distributed over the quinolizinium framework regardless of the attached substituents, whereas delocalization of HOMO is related to the substitution pattern. Electrochemical measurements show irreversible reduction of all compounds, which is supported by the calculated location of LUMO orbitals.
Permanent Link: https://hdl.handle.net/11104/0342565