Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Green C-fixing for a cleaner future

28.11.2011
Copper–carbene catalysts reveal the critical interactions needed to turn waste carbon dioxide into chemical feedstocks

Using fixation reactions to convert free carbon dioxide (CO2) into different organic molecules is an attractive strategy to cut industrial greenhouse gas levels with marginal waste.

Now, broadening the scope of CO2 fixation is possible using a method developed by a research team in Japan led by Zhaomin Hou from the RIKEN Advanced Science Institute in Wako1. The method uses a ‘green’ catalyst system that transforms alkyl–boron molecules into carboxylic acids—an important ingredient for pharmaceutical production.

Organic boron compounds are attractive fixation substrates because they readily participate in carbon–carbon bond-forming reactions. Recently, chemists have used transition metal catalysts to activate hydrocarbons bonded to oxygenated boron esters; addition of CO2 then splits off the activated group and generates a carboxylic acid derivative. However, attempts to reproduce this chemistry with alkylboranes—a widespread class of important synthetic reagents—have had limited success because the so-called ‘catalytic transition metal alkyl’ intermediates are usually unstable and decompose before reacting with CO2.

Hou and colleagues turned to an innovative chemical system to resolve this instability. By combining electron-donating, bulky molecules called N-heterocyclic carbenes (NHCs) with copper atoms, they made metal alkyl complexes that can promote carbon–carbon bond formation with CO2 under mild conditions and at lower cost than most precious metal catalysts—ideal characteristics for sustainably recycling CO2 emissions.

First, the researchers produced an easily activated alkylborane by connecting borabicyclononane (BBN)—a highly strained set of boron–hydrocarbon rings—to the terminal atom of a carbon–carbon double bond. In this approach, the target hydrocarbon for CO2 addition is physically and electronically quite different from the two carbon–boron bonds of the BBN rings.

Hou and colleagues then mixed the alkylborane with the copper–NHC catalyst, a base, and CO2 in a pressurized chamber. After one day at 70 °C, they found that the target had transformed into a new carboxylic acid with near-quantitative yields. Diverse molecules bearing aromatic, halogenated, and bulky functional groups could all act as CO2 fixation substrates using this technique.

The copper–NHC catalyst offered another advantage to the team: a unique chemical environment that enabled isolation of several catalytic intermediates as solid crystals. X-ray measurements of these structures provided the first hard evidence that bonding interactions between alkoxide base molecules, copper atoms, and alkylboranes are critical to enabling CO2 addition (Fig. 1). “Fine-tuning the combination of central metals, bases, and supporting ligands will eventually lead to more efficient and selective catalysts,” notes Hou.

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

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

More articles from Life Sciences:

nachricht Solving the efficiency of Gram-negative bacteria
22.03.2019 | Harvard University

nachricht Bacteria bide their time when antibiotics attack
22.03.2019 | Rice 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: The taming of the light screw

DESY and MPSD scientists create high-order harmonics from solids with controlled polarization states, taking advantage of both crystal symmetry and attosecond electronic dynamics. The newly demonstrated technique might find intriguing applications in petahertz electronics and for spectroscopic studies of novel quantum materials.

The nonlinear process of high-order harmonic generation (HHG) in gases is one of the cornerstones of attosecond science (an attosecond is a billionth of a...

Im Focus: Magnetic micro-boats

Nano- and microtechnology are promising candidates not only for medical applications such as drug delivery but also for the creation of little robots or flexible integrated sensors. Scientists from the Max Planck Institute for Polymer Research (MPI-P) have created magnetic microparticles, with a newly developed method, that could pave the way for building micro-motors or guiding drugs in the human body to a target, like a tumor. The preparation of such structures as well as their remote-control can be regulated using magnetic fields and therefore can find application in an array of domains.

The magnetic properties of a material control how this material responds to the presence of a magnetic field. Iron oxide is the main component of rust but also...

Im Focus: Self-healing coating made of corn starch makes small scratches disappear through heat

Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again.

Superficial micro-scratches on the car body or on other high-gloss surfaces are harmless, but annoying. Especially in the luxury segment such surfaces are...

Im Focus: Stellar cartography

The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.

A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...

Im Focus: Heading towards a tsunami of light

Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.

"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

Solving the efficiency of Gram-negative bacteria

22.03.2019 | Life Sciences

Bacteria bide their time when antibiotics attack

22.03.2019 | Life Sciences

Open source software helps researchers extract key insights from huge sensor datasets

22.03.2019 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>