Synthesis of azafluoranthenes by iridium-catalyzed [2 + 2 + 2] cycloaddition and evaluation of their fluorescence properties.
Takahiro SawanoKaho TakamuraTomoka YoshikawaKayo MurataMarina KogaRisa YamadaTakahide SaitoKazumasa TabataYugo IshiiWataru KashiharaTatsuya NishiharaKazuhito TanabeTadashi SuzukiRyo TakeuchiPublished in: Organic & biomolecular chemistry (2023)
We report a method for the synthesis of azafluoranthenes under neutral reaction conditions in a highly atom-economical manner by the iridium-catalyzed [2 + 2 + 2] cycloaddition of 1,8-dialkynylnaphthalenes with nitriles. A variety of nitriles react with methyl- or phenyl-substituted 1,8-dialkynylnaphthalenes to give a wide range of azafluoranthenes. Azafluoranthenes bearing an amino group show intense fluorescence at around 500 nm. Comparison of the fluorescence properties of amine-substituted azafluoranthenes with related compounds revealed the importance of the amine moiety for obtaining a high fluorescence quantum yield. The choice of the solvent affected the emission maxima and the fluorescence quantum yield. Azafluoranthenes bearing pyrrolidine exhibited blue-shifted emission bands in a non-polar solvent and gave a fluorescence quantum yield of 0.76 in toluene. A Lippert-Mataga plot and computational studies provide insight into the origin of the fluorescence of azafluoranthenes. Furthermore, cellular experiments using human breast adenocarcinoma cells SK-BR-3 demonstrated the feasibility of using azafluoranthenes as fluorescent probes.
Keyphrases
- energy transfer
- single molecule
- molecular dynamics
- quantum dots
- squamous cell carcinoma
- endothelial cells
- molecular docking
- living cells
- induced apoptosis
- room temperature
- small molecule
- radiation therapy
- single cell
- oxidative stress
- cell death
- photodynamic therapy
- molecular dynamics simulations
- cell cycle arrest
- induced pluripotent stem cells
- pi k akt