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
Reptile vocalization is surprisingly flexible
30.05.2017 | Max-Planck-Institut für Ornithologie
New photocatalyst speeds up the conversion of carbon dioxide into chemical resources
29.05.2017 | DGIST (Daegu Gyeongbuk Institute of Science and Technology)
The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde.
The researchers demonstrated the feasibility of using plasma to amplify short laser pulses of picojoule-level energy up to 100 millijoules, which is a 'gain'...
Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.
Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
30.05.2017 | Life Sciences
30.05.2017 | Power and Electrical Engineering
29.05.2017 | Earth Sciences