Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Move to the red!

13.09.2010
Design and synthesis of rigid fluorophores

Stable dyes with sharp absorption and fluorescence emission bands in the red or NIR region of the spectrum, combined with high molar absorption coefficients and high fluorescence quantum yields, may find extensive use in many different fields, such as optical engineering, analytical chemistry, biological in vivo imaging and sensing applications, and materials science. In Chemistry—An Asian Journal, Wim Dehaen and co-workers, based at Katholieke Universiteit Leuven (Belgium), Lanzhou University (China), and the Université de Mons (Belgium) describe the preparation of difluoroboron dipyrromethene (BODIPY)-based dyes with increasing conformational rigidity that have absorption in the visible region of the spectrum.


Although a substantial number of BODIPY dye analogues have been developed, primarily through extended conjugation using aryl substituents, the substituted BODIPY dyes show red shifts of over 100 nm but have only low to moderate fluorescence quantum yields owing to non-radiative decay arising from the non-rigid nature of compounds. Alkenyl, and more-recently alkynyl substituents afforded large red shifts, but the rigidity of the triple bond generally results in higher quantum yields. Functionalization of the aromatic rings attached to the BODIPY core with heterocyclic rings even led to near infrared (NIR) emission; however, these dyes require lengthy multi-step syntheses of the fused-ring pyrrole starting materials and are restricted in scope to symmetrical frameworks.

Two BODIPY dyes were synthesized from a conformationally unconstrained indacene using simple palladium catalysis. These dyes showed restricted rotation of their phenoxy moieties, and thus absorb and fluoresce more intensely at longer wavelengths relative to their unrestricted analogues. Furthermore, reduction of the conformational flexibility in these dyes led to significantly higher fluorescence quantum yields. Quantum chemical calculations were also performed which showed that the increase in conformational constraint led to larger spectroscopic shifts. X-ray diffraction analysis showed a progressive increase in the extended planarity of the chromophore in line with increasing conformational rigidity, which explained the larger red shifts in the absorption and emission spectra.

This practically simple design strategy provides promise for the rapid development of new BODIPY-based dyes with increasing structural rigidity. Furthermore, the development of novel dyes with extended planarity is expected to afford higher quantum yields and more-substantial bathochromic shifts into the NIR region, which may find interesting application in a wide variety of fields.

Author: Wim Dehaen, Katholieke Universiteit Leuven (Belgium), http://chem.kuleuven.be/organ/losa/index.htm

Title: Synthesis, Spectroscopy, Crystal Structure Determination, and Quantum Chemical Calculations of BODIPY Dyes with Increasing Conformational Restriction and Concomitant Red-Shifted Visible Absorption and Fluorescence Spectra

Chemistry - An Asian Journal 2010, 5, No. 9, 2016–2026, Permalink to the article: http://dx.doi.org/10.1002/asia.201000248

Wim Dehaen | Chemistry - An Asian Journal
Further information:
http://www.chemasianj.org
http://chem.kuleuven.be/organ/losa/index.htm

More articles from Life Sciences:

nachricht World’s Largest Study on Allergic Rhinitis Reveals new Risk Genes
17.07.2018 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Plant mothers talk to their embryos via the hormone auxin
17.07.2018 | Institute of Science and Technology Austria

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Microscopic trampoline may help create networks of quantum computers

17.07.2018 | Information Technology

In borophene, boundaries are no barrier

17.07.2018 | Materials Sciences

The role of Sodium for the Enhancement of Solar Cells

17.07.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>