Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Sensitive to Oxygen

04.03.2011
Phosphorescent iridium(III) porphyrin complexes, new tunable oxygen indicators

Monitoring the amount of oxygen in living tissues accurately is a valuable tool in biomedical science, because it enables the elucidation of the course of metabolic processes or the detection of diseases or anomalies.

Metal complexes that absorb and emit light are useful as sensors, and metal complexes of porphyrins and their derivatives are especially good candidates for such applications, as the porphyrin macrocycle can easily be modified.

Sergey M. Borisov and his co-workers at Graz University of Technology (Austria), developed new, strongly phosphorescent porphyrin complexes of iridium(III), which were applied as dyes in advanced optical oxygen-sensing materials and published them in the European Journal of Inorganic Chemistry.

Photophysical properties of porphyrin complexes of metals such as palladium or platinum have been studied before; however, there are fewer studies on iridium complexes, which are more difficult to synthesize. The absorption bands of iridium complexes are broader and are shifted to lower wavelengths in comparison to those of their platinum analogues. This enables them to be excited by visible light. Furthermore, iridium(III) is hexacoordinate, which opens up the added possibility of introducing axial ligands directly on the metal instead of modifying the porphyrin macrocycle, in contrast to the square-planar platinum(II) and palladium(II) analogues. A π-extended iridium(III)–benzoporphyrin and four iridium(III)–octaethylporphyrin complexes with high room-temperature phosphorescence quantum yields of up to 30% were synthesized. Axial ligands were used to change their solubility or to introduce binding groups. In this way, the complexes were rendered soluble in organic solvents, and they were incorporated into polystyrene or other polymers to yield oxygen sensors. In addition, other axial ligands, such as an imidazole ligand bearing a carboxyl group, were used to make the complexes soluble in polar solvents such as ethanol and even in aqueous buffer at physiological pH, which enabled coupling to biomolecules such as proteins, antibodies, or lipids, as demonstrated by coupling to bovine serum albumin.

The importance of these new compounds is their tunable photophysical properties and versatility, as demonstrated by their application as a water-soluble oxygen probe (by staining bovine serum albumin) and a trace oxygen sensor (by coupling to amino-modified silica gel). The obtained sensor is sensitive to small oxygen concentrations and features a highly linear calibration plot. The new dyes are particularly promising as indicators for oxygen sensors with tailor-made sensitivity.

Author: Sergey Borisov, Technische Universität Graz (Austria), http://www.analytchem.tugraz.at/sensors/borisov.php

Title: Strongly Phosphorescent Iridium(III)–Porphyrins—New Oxygen Indicators with Tuneab­le Photophysical Properties and Functionalities

European Journal of Inorganic Chemistry, Permalink to the article: http://dx.doi.org/10.1002/ejic.201100089

Sergey Borisov | Wiley-VCH
Further information:
http://www.wiley.com

More articles from Life Sciences:

nachricht Link Discovered between Immune System, Brain Structure and Memory
26.04.2017 | Universität Basel

nachricht Researchers develop eco-friendly, 4-in-1 catalyst
25.04.2017 | Brown University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

Scientist invents way to trigger artificial photosynthesis to clean air

26.04.2017 | Materials Sciences

Ammonium nitrogen input increases the synthesis of anticarcinogenic compounds in broccoli

26.04.2017 | Agricultural and Forestry Science

SwRI-led team discovers lull in Mars' giant impact history

26.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>