Past Event

Chemistry Colloquium, Presented by Prof. Bo W. Laursen

October 12, 2022
10:00 AM - 11:30 AM
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Miller Room - 328 Havemeyer

Design of fluorescent supramolecular dyes and materials

Presented by Prof. Bo W. Laursen


Brightly fluorescent dyes are highly desirable tools in bioimaging and as building blocks for optoelectronic materials.

In this talk I will first introduce our work on synthesis and photophysical properties of fluorescent triangulenium dyes, before turning to recent work on synthesis and studies of a dyad combining the long fluorescence lifetime (~20ns) of the diazaoxatriangulenium (DAOTA) with the high absorption efficiency of perylenediimide (PDI).1 The PDI-DAOTA dyad display 100% energy transfer from PDI to DAOTA while maintaining the long fluorescence lifetime of DAOTA. The highly increased brightness of the dyad for the first time allows time-gated single molecule imaging.

In the second part of the talk I will present our work on a general approach to fluorescent solid-state materials based on organic dyes. In most materials based on efficient molecular dyes the close contact between the π-systems leads to strong electronic coupling and quenching of the fluorescence. Recently, we developed a supramolecular method that UV-excitation of the anion efficiently isolate fluorophores while in parallel ensuring very high densities of the dyes.2 These SMILES (small molecule ionic isolation lattices) materials are simple to make by mixing a cationic dye with an anion-binding and structure-directing cyanostar3 macrocycle. The macrocycle sequesters the dye’s counter anion creating a wide band-gap complex that hierarchically directs alternating charge-by-charge packing for spatial and electronic isolation of the dyes in the SMILES crystals. The supramolecular SMILES principle can be translated to nanoparticles in water with potential applications in bioimaging.4 complex can be used to further boost the brightness of the materials via FRET to the dye, while FRET between different donor and acceptor dyes imbedded in the same SMILES lattice can be used to obtain control of fluorescence lifetime and improving quantum yields even further.5, 6

1. Kacenauskaite, L.; Bisballe, N.; Mucci, R.; Santella, M.; Pullerits, T.; Chen, J.; Vosch, T.; Laursen, B. W., Rational Design of Bright Long Fluorescence Lifetime Dyad Fluorophores for Single Molecule Imaging and Detection. J Am Chem Soc 2021, 143, 1377-1385.
2. Benson, C. R.; Kacenauskaite, L.; VanDenburgh, K. L.; Zhao, W.; Qiao, B.; Sadhukhan, T.; Pink, M.; Chen, J.; Borgi, S.; Chen, C.-H.; Davis, B. J.; Simon, Y. C.; Raghavachari, K.; Laursen, B. W.; Flood, A. H., Plug-and-Play Optical Materials from Fluorescent Dyes and Macrocycles. Chem 2020, 6, 1978-1997.
3. Lee, S.; Chen, C.-H.; Flood, A. H., A pentagonal cyanostar macrocycle with cyanostilbene CH donors binds anions and forms dialkylphosphate [3]rotaxanes. Nat Chem 2013, 5, 704-710.
4. Chen, J.; Fateminia, S. M. A.; Kacenauskaite, L.; Baerentsen, N.; Gronfeldt Stenspil, S.; Bredehoeft, J.; Martinez, K. L.; Flood, A. H.; Laursen, B. W., Ultrabright Fluorescent Organic Nanoparticles Based on Small-Molecule Ionic Isolation Lattices*. Angew Chem Int Ed Engl 2021, 60, 9450-9458.
5. Kacenauskaite L, S. S., Olsson AH, Flood AH, Laursen BW, A Universal Concept for Bright, Organic Solid State Emitters - Doping of Small Molecule Ionic Isolation Lattices with FRET Acceptors. ChemRxiv (pre-print) 2022.
6. Chen, J. S.; Stenspil, S. G.; Kaziannis, S.; Kacenauskaite, L.; Lenngren, N.; Kloz, M.; Flood, A. H.; Laursen, B. W., Quantitative Energy Transfer in Organic Nanoparticles Based on Small-Molecule Ionic Isolation Lattices for UV Light Harvesting. Acs Applied Nano Materials 2022.


More About Prof. Laursen
Host By Colin Nuckolls

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(212) 854-2202