Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Putting the squeeze on rare earth metals

18.04.2011
‘Pincer’ molecules trap reactive rare earth elements into previously unseen hydrogen-infused structures

Rare-earth metals are a series of elements that represent one of the final frontiers of chemical exploration. The vigorous reactivity of these substances, however, has made it difficult for researchers to transform them into stable materials with well-defined structures. But when they succeed, the payoff can be enormous—rare-earth compounds have important applications in areas ranging from catalysis to clean energy.

Now, Zhaomin Hou and colleagues from the RIKEN Advanced Science Institute in Wako have discovered a new way to isolate rare-earth metals as hydrogen-infused crystals by using wedge-shaped bis(phosphinophenyl)amido (PNP) ligands to ‘pinch’ them in place[1]. These ligands squeeze rare-earth yttrium atoms together tighter than any previous material, and can even stabilize highly volatile charged complexes.

Metallic compounds that incorporate multiple hydrogen atoms, or polyhydrides, into their frameworks are useful to chemists because they provide some of the purest understandings of bonding and reactivity available. Previously, Hou’s team isolated an yttrium polyhydride containing a hydrogen ligand that simultaneously bonds to four metals[2]. This compound sparked remarkable chemical curiosity because of its structural novelty.

According to Hou, the trick to producing rare-earth polyhydrides is to surround them with large, cumbersome molecules that easily pack together to form crystals. The distinct structure of PNP ligands—two phosphorus atoms, linked together by a rigid aromatic–amino core that can bind to metals with a pincer-like grip—made this ligand a promising candidate for the researchers’ investigation.

By first substituting extra methyl units onto the aromatic backbone of PNP to increase its bulkiness, and then mixing the ligand with an yttrium alkyl precursor and hydrogen gas, the team synthesized pale yellow crystals of a new yttrium polyhydride complex. X-ray structural analysis revealed that three yttrium atoms, held in place by PNP ‘pincers’, were interlinked by a set of double- and triple-bridged hydrogen ligands (Fig. 1). This intricate network of bonds produced the shortest yttrium–yttrium distance ever recorded—an extraordinary packing density that may be critical for future hydrogen-storage applications.

The researchers found that an ammonium proton could remove a hydride from the complex without disrupting crystallization, yielding the first-ever cationic tri- and di-yttrium polyhydrides. The charged nature of these materials should impart potent chemical activity, attributes which Hou and his team are currently investigating. “Our results clearly demonstrate the vital importance of ligand-tuning in the isolation and characterization of rare earth polyhydrides, and should encourage further explorations in this burgeoning area,” he says.

The corresponding author for this highlight is based at the Organometallic Chemistry Laboratory, RIKEN Advanced Science Institute

Journal information

[1] Cheng, J., Shima, T. & Hou, Z. Rare-earth polyhydride complexes bearing bis(phosphinophenyl)amido pincer ligands. Angewandte Chemie International Edition 50, 1857–1860 (2011).

[2] Hou, Z., Nishiura, M. & Shima, T. Synthesis and reactions of polynuclear polyhydrido rare earth metal complexes containing “(C5Me4SiMe3)LnH2” units: A new frontier in rare earth metal hydride chemistry. European Journal of Inorganic Chemistry 18, 2535–2545 (2007).

gro-pr | Research asia research news
Further information:
http://www.rikenresearch.riken.jp/eng/research/6567
http://www.researchsea.com

More articles from Life Sciences:

nachricht Symbiotic bacteria: from hitchhiker to beetle bodyguard
28.04.2017 | Johannes Gutenberg-Universität Mainz

nachricht Nose2Brain – Better Therapy for Multiple Sclerosis
28.04.2017 | Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB

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

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | 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

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>