Space Industry and Business News  





.
TECH SPACE
Direct Observation Of Carbon Monoxide Binding To Metal-Porphyrines

A scanning tunneling microscopy image (left) shows four porphyrins. The models (right) illustrate the two systems shown in the picture. The protrusions correspond to the central atom (yellow sphere) and the two elevated portions to the saddle (orange). The characteristic cross shape results from the attached carbon monoxide molecules (red and blue). Credit: Knud Seifert (TUM)
by Staff Writers
Munich, Germany (SPX) Jan 11, 2011
The mechanism for binding oxygen to metalloporphyrins is a vital process for oxygen-breathing organisms. Understanding how small gas molecules are chemically bound to the metal complex is also important in catalysis or the implementation of chemical sensors.

When investigating these binding mechanisms, scientists use porphyrin rings with a central cobalt or iron atom. They coat a copper or silver support surface with these substances.

An important characteristic of porphyrins is their conformational flexibility. Recent research has shown that each specific geometric configuration of the metalloporphyrins has a distinct influence on their functionality. In line with the current state of research, the scientists expected only a single CO molecule to bind axially to the central metallic atom.

However, detailed scanning tunnel microscopy experiments by Knud Seifert revealed that, in fact, two gas molecules dock between the central metallic atom and the two opposite nitrogen atoms. Decisive is the saddle shape of the porphyrin molecules, in which the gas molecules assume the position of the rider.

The significance of the saddle geometry became apparent in model calculations done by Marie-Laure Bocquet from the University of Lyon. Her analysis helped the researchers understand the novel binding mode in detail. She also showed that the shape of the molecular saddle remains practically unchanged, even after the two gas molecules bind to the porphyrin.

The porphyrins reacted very differently when the researchers replaced the carbon monoxide with stronger-binding nitrogen monoxide. As expected, this binds directly to the central atom, though only a single molecule fits in each porphyrin ring.

This has a significant effect on the electronic structure of the carrier molecule, and the characteristic saddle becomes flattened. Thus, the porphyrin reacts very differently to different kinds of gas - a result that is relevant for potential applications, such as sensors.

Dr. Willi Auwaerter, one of the authors, is thrilled: "What's new is that we actually saw, for the first time, the mechanism on a molecular level. We even can selectively move individual gas molecules from one porphyrin to another."

The team aims to explain the physical and chemical processes on surfaces and in nanostructures. Once these fundamental questions are answered, they will take on new challenges: How big is the influence of the central atom?

How does the binding change in planar conformations? How can such systems be utilized to implement catalyzers and sensors through controlled charge transfers?

Cis-dicarbonyl binding at cobalt and iron porphyrins with saddle-shape conformation, Knud Seufert, Marie-Laure Bocquet, Willi Auwarter, Alexander Weber-Bargioni, Joachim Reichert, Nicolas Lorente und Johannes V. Barth, Nature Chemistry, Online 9. January 2011 - DOI: 10.1038/NCHEM.956.

Discriminative Response of Surface-Confined Metalloporphyrin Molecules to Carbon and Nitrogen Monoxide, Knud Seufert, Willi Auwaerter und Johannes V. Barth, Journal of the American Chemical Society, 2010, 132, 18141? - DOI: 10.1021/ja1054884




Share This Article With Planet Earth
del.icio.usdel.icio.us DiggDigg RedditReddit
YahooMyWebYahooMyWeb GoogleGoogle FacebookFacebook



Related Links
Technische Universitaet Muenchen
Space Technology News - Applications and Research



Tempur-Pedic Mattress Comparison

Newsletters :: SpaceDaily Express :: SpaceWar Express :: TerraDaily Express :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News
TECH SPACE
New Glass Tops Steel in Strength and Toughness
Berkeley, Germany (SPX) Jan 11, 2011
Glass stronger and tougher than steel? A new type of damage-tolerant metallic glass, demonstrating a strength and toughness beyond that of any known material, has been developed and tested by a collaboration of researchers with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab)and the California Institute of Technology. What's more, even better versions of ... read more

.
Get Our Free Newsletters Via Email
  


TECH SPACE
Google buys eBook Technologies

Direct Observation Of Carbon Monoxide Binding To Metal-Porphyrines

Liquid Pistons Could Drive New Advances In Camera Lenses And Drug Delivery

How Do You Make Lithium Melt In The Cold

TECH SPACE
JICO Support System Receives Production Approval

Northrop Grumman Demonstrates MR-TCDL Capabilities

IBCS Completes Warfighter-Centered Design Exercises

Arianespace Will Orbit Sicral 2 Milcomms Satellites

TECH SPACE
ISRO To Launch Two Communication Satellites This Year

Arianespace Will Have A Record Year Of Launch Activity In 2011

2011: The Arianespace Family Takes Shape

ISRO To Launch Singapore's First Satellite In Orbit In February

TECH SPACE
China schools issue GPS phones to boost safety

Another GPS Software Upgrade Completed

GPSCaddy Golf App Now Offers Free Course Maps

ISRO To Implement Regional Navigation Satellite System

TECH SPACE
Runways change as magnetic north moves

Beijing to build second major airport

China's first stealth fighter makes maiden flight: reports

Bids in for British flight training system

TECH SPACE
Intel earnings soar with rise of "cloud" computing

Intel to pay NVIDIA billons in patent dispute

Greenpeace ranks 'greenest' electronics

Better Control Of Building Blocks For Quantum Computer

TECH SPACE
NASA Image Shows La Nina-Caused Woes Down Under

Google illegally gathered data in S.Korea: police

Sat-nav turtles go on trans-ocean trek

Cyclone Tasha Adds To Severe Flooding Over Eastern Australia

TECH SPACE
Gulf Methane Gas Concentrations Have Returned To Near-Normal Levels

UN warns over lead poisoning in northern Nigeria

Kenya bans plastic bags

Oceanic "Garbage Patch" Not Nearly As Big As Portrayed In Media


The content herein, unless otherwise known to be public domain, are Copyright 1995-2010 - SpaceDaily. AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement