Two‐photon Excitation of Bright Diaza[4]Helicenes for Isotropic and Circularly Polarized Emission
Year: 2025
Type: article
Abstract: Helicenes are chiral organic dyes that are attracting growing attention due to the high tunability of their (chir)optical and electronic properties. In this work, a series of functionalized cationic diaza[4]helicenes based on dimethoxyquinacridinium (DMQA) scaffolds are presented. By merging branched N‐alkyl side chains and triple para‐functionalization with OMe groups, structures combine improved chiroptical responses (5x increase) and strong fluorescence quantum yields (Φf ≈ 70% in acetonitrile). An overall improved efficiency of the emission of circularly polarized light with BCPL values reaching 3.4 M−1 cm−1 is obtained. Additionally, two‐photon excitation (2PE) studies were performed, showing good values of cross section (CS) at 810 nm. Interestingly, 2PE circularly polarized luminescence (CPL) spectra were acquired for the most performant derivatives (N‐isopropyl and N‐cyclohexyl); this type of measurement being usually challenging for organic molecular species. Finally, the viability of these compounds in single‐photon (1PE) and 2PE microscopy is also shown.
Source: Chemistry - A European Journal
Institutions: University of Geneva, Durham University
Language: English
Subfield: Organic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,640
Funders: National Science Foundation, European Commission, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Université de Genève, Horizon 2020 Framework Programme, HORIZON EUROPE Framework Programme, Engineering and Physical Sciences Research Council, Biotechnology and Biological Sciences Research Council, Research Executive Agency
Awards: G1276317268, Helical systems for chiral organic light emitting diodes, G2001806450, G2188020438, Circularly Polarised Luminescence Laser Scanning Confocal Microscopy, G3345895242, G3635379844, G3799452210, G4937468798, Circularly Polarised Luminescent Photography and Lanthanide Complexes for Advanced Intelligent Security Applications, G6281504974, G628552264, G6612792509, Superstable Chiral Cations and Reactive Ylides for Synthesis, Catalysis and Optical Applications, G7628805400, NanoDrill - A new versatile research tool - high spatial resolution light activated molecular nanomachines, G7984235579, G8512683158
OpenAlex ID: W4409663735