Carbon dioxide contributes to the greenhouse effect, but practicable solutions for its capture and storage have not really been found.
However, it might be possible to kill two birds with one stone if carbon dioxide could be used as a raw material. Unlike the carbon sources commonly used today—fossil fuels and natural gas— carbon dioxide is a renewable resource and an environmentally friendly chemical reagent.
Unfortunately, the carbon–oxygen bonds are too strong to be broken easily. Until now, this has mainly been achieved with the use of metal-containing catalysts. A German–Canadian cooperative effort has now developed a new concept that works without metals: as they report in the journal Angewandte Chemie, the team led by Gerhard Erker and Stefan Grimme at the University of Münster and Douglas W. Stephan at the University of Toronto uses so-called frustrated Lewis acid/base pairs to reversibly bind carbon dioxide under mild conditions.
An organic borane and an organic phosphine form a typical Lewis pair: As a Lewis base, the phosphine has too many electrons. The borane on the other hand, a Lewis acid, has an electron deficiency. The Lewis base thus makes its free electron pair available to the Lewis acid. The phosphine and borane form an adduct that is held together by way of the shared electron pair. However, if both partners have bulky side groups, they cannot come together to form the desired bond. They are then described as a “frustrated” Lewis pair.
The researchers exposed a solution of such a frustrated pair to an atmosphere of CO2 under two bars of pressure. This immediately resulted in a reaction, which formed a white solid. What happened? The phosphorus atom in the frustrated phosphine uses its electron pair to bind to the carbon of the CO2, and the boron atom of the frustrated borane snaps up the free electron pair of one of the oxygen atoms of the CO2 and binds to it. In this way, the carbon dioxide couples the two partners together, alleviating their frustration.
With the application of heat or certain solvents, the carbon dioxide can be released and the Lewis pair returned to its original frustrated state. The researchers are now investigating how the captured CO2 could be chemically transformed for use as a feedstock.
Author: Gerhard Erker, Universität Münster (Germany), http://www.uni-muenster.de/Chemie.oc/erker/index.html
Title: Reversible Metal-Free Carbon Dioxide Binding by Frustrated Lewis Pairs
Angewandte Chemie International Edition, doi: 10.1002/anie.200901636
Gerhard Erker | Angewandte Chemie
Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München
Second research flight into zero gravity
21.10.2016 | Universität Zürich
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.
Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
21.10.2016 | Health and Medicine
21.10.2016 | Information Technology
21.10.2016 | Materials Sciences