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 A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht On the way to developing a new active ingredient against chronic infections
18.08.2017 | Deutsches Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>