Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Converting Nitrogen to a More Useful Form

09.01.2007
Nitrogen fixation: Hafnium complex couples atmospheric nitrogen with carbon dioxide

Nitrogen-containing organic compounds are important products as well as intermediates for many pharmaceuticals, agrochemicals, and chemicals used in electronics. Air contains plenty of nitrogen, but it is in a form that cannot be used for chemical syntheses: nitrogen gas, a molecule made of two nitrogen atoms, is highly inert. The main source of nitrogen today involves a detour by way of synthetic ammonia, a process requiring a lot of energy and explosive hydrogen gas under harsh conditions.

In order to find synthetic pathways that do not rely on ammonia, scientists are searching for ways to fix atmospheric nitrogen in the form of higher-value organic compounds. Chemists working with Paul J. Chirik at Cornell University (Ithaca, New York) have now found an interesting new method, which they describe in the journal Angewandte Chemie: they have bound nitrogen to carbon dioxide while maintaining the nitrogen–nitrogen bond, forming a hydrazine derivative. The metal hafnium promotes this reaction.

The two nitrogen atoms in a nitrogen molecule are so happy with each other that they have little incentive to enter into chemical bonds with other atoms. Direct formation of a bond between carbon and nitrogen, a requirement for the formation of organonitrogen compounds without resorting to ammonia, is a serious challenge for scientists. The nitrogen has to be “outsmarted”. While it does not easily enter into chemical bonds with organic substances, molecular nitrogen does have a tendency to form coordination complexes by binding to a metal. When the nitrogen acts as ligand in these complexes, it receives electrons from the metal atom disrupting the strong nitrogen-to-nitrogen triple bond. Chemists often refer to this process as “activating” the nitrogen ligand, as new chemistry is now possible.

... more about:
»Atom »Carbon »Hafnium »compound »dioxide »nitrogen

Chirik and his co-workers found out that the nitrogen gets activated just right in a hafnocene complex (whose hafnium atoms each have two aromatic five-membered carbon rings as additional ligands), in which the nitrogen molecule is grabbed side-on by two hafnium atoms,. Carbon dioxide can then react with the activated nitrogen molecule. Two carbon dioxide molecules push their way in between the nitrogen and the hafnium. One of the two nitrogen atoms thus forms two strong new bonds to two carbon atoms from the carbon dioxide. One of the nitrogen–nitrogen bonds remains intact. By using an organosilicon compound, the cores of the hafnocene complexes can be released—in the form of a silicon-containing organic hydrazine derivative.

Author: Paul J. Chirik, Cornell University, Ithaca (USA), http://www.chem.cornell.edu/faculty/index.asp?fac=19

Title: Nitrogen–Carbon Bond Formation from N2 and CO2 Promoted by a Hafnocene Dinitrogen Complex Gives Access to a Substituted Hydrazine

Angewandte Chemie International Edition, doi: 10.1002/anie.200604099

| Angewandte Chemie
Further information:
http://www.chem.cornell.edu/faculty/index.asp?fac=19
http://pressroom.angewandte.org.
http://www.wiley.co.uk

Further reports about: Atom Carbon Hafnium compound dioxide nitrogen

More articles from Life Sciences:

nachricht Single-stranded DNA and RNA origami go live
15.12.2017 | Wyss Institute for Biologically Inspired Engineering at Harvard

nachricht New antbird species discovered in Peru by LSU ornithologists
15.12.2017 | Louisiana State 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: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>