Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Zirconium takes the strain from carbon rings: 'Impossible' molecule undergoes improbable chemistry

Figure 1: Pushing back the boundaries of chemistry. This molecular structure shows a zirconium atom (green) sitting in a ring with four other carbon atoms (purple) in the new cycloallene compound. In the background, the chemical reaction shows the interconversion between alkyne and allene.
Figure 1: Pushing back the boundaries of chemistry. This molecular structure shows a zirconium atom (green) sitting in a ring with four other carbon atoms (purple) in the new cycloallene compound. In the background, the chemical reaction shows the interconversion between alkyne and allene.

Abstract:
An unusual molecule once thought to be too strained to exist has been transformed into another contorted compound by RIKEN chemists, testing the limits of how far carbon-based molecules can be distorted by combining them with metal atoms.

Zirconium takes the strain from carbon rings: 'Impossible' molecule undergoes improbable chemistry

Japan | Posted on September 12th, 2008

The complexity of organic chemistry is largely due to the tendency of carbon atoms to join together into chains and rings. Yet carbon-carbon triple bonds (-C≡C-, also known as alkynes) are relatively rare in ring systems, because they prefer to connect to other atoms in straight lines.

It's just about possible to bend this alkyne group so that it will fit into a ring of seven carbon atoms. But smaller rings are extremely reactive, due to the strain put on that triple bond, explains Noriyuki Suzuki of RIKEN's Advanced Science Institute in Wako. "It was believed that it was impossible to isolate them in a pure form," he says.

However, in 2002 Suzuki's team reported that they had made a ring of just five atoms which included an alkyne group, yet was extremely stable and could be isolated as crystals. Their secret was that one of the atoms in the ring was a zirconium atom1.

The researchers are now exploring how this molecule behaves. Recently, they have used it to create another ring system containing two carbon-carbon double bonds sitting side by side (-C=C=C-), also known as an allene. Under normal circumstances a five-membered ring containing an allene would be too strained to exist for long—but with the zirconium atom in place, the team found that the cycloallene compound could be isolated (Fig. 1).

The team made the compound by mixing lithium or potassium into a solution of their zirconium-alkyne ring, which gave it a negative charge and a deep blue color. Adding a reagent such as iodomethane then formed the cycloallene—although the team was surprised that adding a source of hydrogen atoms formed a mixture of a cycloallene and a cycloalkene, which contained just a single carbon-carbon double bond2.

Suzuki says that these compounds are unlikely to have any practical uses. Instead, the research pushes back the boundaries of chemistry that would once have been thought impossible. Suzuki notes that another group recently made a similar compound which included a hafnium atom3.

The team is now testing the physical and chemical properties of the new compounds, and trying to clarify exactly why these molecules are so stable.
Reference

1. Suzuki, N., Nishiura, M. & Wakatsuki, Y. Isolation and structural characterization of 1-zirconacyclopent-3-yne, five-membered cyclic alkynes. Science 295, 660-663 (2002).
2. Suzuki, N., Hashizume, D., Koshino, H. & Chihara, T. Transformation of a 1-zirconacyclopent-3-yne, a five-membered cycloalkyne, into a 1-zirconacyclopent-3-ene and formal "1-zirconacyclopenta-2,3-dienes". Angewandte Chemie International Edition 47, 5198-5202 (2008). | article |
3. Ugolotti, J., Dierker, G., Kehr, G., Fröhlich, R., Grimme, S. & Erker, G. Five-membered metallacyclic allenoids: synthesis and structure of remarkably stable strongly distorted cyclic allene derivatives. Angewandte Chemie International Edition 47, 2622-2625 (2008).

####

For more information, please click here

Copyright © Riken

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

'Exotic' material is like a switch when super thin April 18th, 2014

Innovative strategy to facilitate organ repair April 18th, 2014

Oxford Instruments Asylum Research Introduces the MFP-3D InfinityTM AFM Featuring Powerful New Capabilities and Stunning High Performance April 18th, 2014

Conductive Inks: booming to $2.8 billion by 2024 April 17th, 2014

Harris & Harris Group Continues Its Blog Series to Highlight Most Impactful Portfolio Companies With Champions Oncology, Inc. April 17th, 2014

Chemistry

Thinnest feasible membrane produced April 17th, 2014

Targeting cancer with a triple threat: MIT chemists design nanoparticles that can deliver three cancer drugs at a time April 15th, 2014

Scientists Succeed in Simultaneous Determination of Acetaminophen, Codeine in Drug Samples April 9th, 2014

Discoveries

'Exotic' material is like a switch when super thin April 18th, 2014

Innovative strategy to facilitate organ repair April 18th, 2014

Thinnest feasible membrane produced April 17th, 2014

More effective kidney stone treatment, from the macroscopic to the nanoscale April 17th, 2014

Announcements

'Exotic' material is like a switch when super thin April 18th, 2014

Innovative strategy to facilitate organ repair April 18th, 2014

Oxford Instruments Asylum Research Introduces the MFP-3D InfinityTM AFM Featuring Powerful New Capabilities and Stunning High Performance April 18th, 2014

Transparent Conductive Films and Sensors Are Hot Segments in Printed Electronics: Start-ups in these fields show above-average momentum, while companies working on emissive displays such as OLED are fading, Lux Research says April 17th, 2014

NanoNews-Digest
The latest news from around the world, FREE







  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More














ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE