Research Highlight
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The structure of crystalline polymer electrolyte Poly(ethylene oxide)6:LiAsF6. Left: Lithium cations (blue) are located within cylindrical tunnels formed by two separate poly(ethylene oxide) chains (showed in green and red). Right: Side view. The cations are coordinated (thin lines) by ether oxygens of the polymer chains with the AsF6- anions (white and purple) floating in the interchain space. (Prof Peter Bruce group). |
Concerns about the future of global oil and gas reserves, the resulting expected rise in energy prices and the effects of continuing to burn fossil fuels, such as climate change and air pollution, make it essential to improve energy efficiency in the short term and look to new, more sustainable ways of generating our energy in the future. Renewable energy, from wind, wave and tidal generators, solar power, fuel cells and improved rechargeable batteries will all play an important role in this, perhaps in an energy economy largely based on hydrogen. The School of Chemistry at St Andrews is an internationally-recognised centre for research in some of these areas, especially in new materials and concepts for Solid Oxide Fuel Cells and for rechargeable lithium batteries. Fuel cells convert the chemical energy from the electrochemical oxidation of a fuel, such as hydrogen, directly into electrical energy and are capable of efficiencies several times higher than for an internal combustion engine. Rechargeable lithium batteries offer a very flexible and light-weight way of storing and supplying energy suitable for use in portable electronic devices. Recent achievements at St Andrews include the launch of a company to develop the new SOFCroll fuel cell concept (Prof. Irvine) and the discoveries of new electrode materials to allow the direct use of methane in fuel cells (Dr Baker) and a whole new class of crystalline polymers for use as Li+-conducting electrolytes for Li batteries (Prof Bruce).
Research Highlight
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| PSC electron micrograph |
Porous single crystals (PSC) of metal oxides have been investigated and developed into self-supported nanoscale catalysts by Dr Wuzong Zhou's research group. They have produced PSC of Cr2O3 and WO3 using mesoporous SBA-15 as the template. Recent work includes PSC Cr2O3 and Co3O4 using cubic mesoporous KIT-6 as a template. Read more.
Research Highlight
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| STM image of DPP on a Cu surface |
Diketo-diphenyl-pyrrolo-pyrrole (DPP), an important red pigment molecule, is adsorbed on a partially oxidised Cu(110) surface. The picture shows a scanning tunneling microscope (STM) image of three molecules lying parallel on the surface; the individual rings of the molecule are easily recognised. Click on the picture for a larger image. (Image provided by Dr Steve Francis and Prof Neville Richardson)
Research Highlight
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| SAM formation |
Molecules forming SAMs consist of a head group (H) as a linker between the molecule and the substrate, a spacer, and a tail group (T) which allows one to vary the surface properties in a wide range. For example, changing from terminal CH3 to OH groups alters the wetting properties from hydrophobic to hydrophilic. Other possibilities include the attachment of redox active moieties or proteins which is of interest for a variety of applications, e.g. as (bio)-sensors. Dr Manfred Buck and his research team's efforts focus on the elucidation of the factors determining film formation and structures of SAMs in order to control their properties down to nanometer dimensions.Read more.
Research Highlight
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| The ferroelectric (left) and paraelectric (right) phases of Bi2WO6 |
Dr Phil Lightfoot's group is interested in the design, synthesis and characterisation of advanced inorganic materials with novel physical and chemical properties, and the understanding of the interplay of structure, composition and properties. They are using the principles of solid state chemistry to design new mixed metal oxides and oxyhalides related to the perovskite family which are expected to show interesting ferroelectric behaviour. These materials, for example SrBi2Ta2O9, are being used as information storage media, for example in smart cards. Detailed understanding of the crystal structures and properies of these materials aids in the design of new compositions. Read more.
Research Highlight
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| First native fluorination enzyme. |
Professor David O'Hagan's group have a general interest in bio-organic chemistry and a particular interest in fluorine chemistry. Recently they have been exploring methods for biological fluorination and have isolated an enzyme from a bacterium (Streptomyces cattleya) which can form C-F bonds. Recently Profs O'Hagan and Naismith reported the sequence and three-dimensional structureof the first native fluorination enzyme, 50-fluoro-50-deoxyadenosine synthase, from Streptomyces cattleya.This enzyme is the first of its class and they are now exploring the mechanism of this enzyme and assessing its applications. They are also exploring other enzymes in the bacterium which are also involved in fluorometabolite biosynthesis which carry out novel chemistry. They are also are interested in exploiting stereoelectronic effects associated with the C-F bond and consequently using the C-F bond as a tool to influence the solution conformation of organic compounds. Such molecules include fatty acids, amino acids and carbohydrates. These activities may extend the group's research interests into the area of materials chemistry (e.g. the synthesis of novel liquid crystals).Read more.
View 3D structure of the enzyme
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| Molecules found in broccoli inspire synthesis of biologically active molecules. |
Glucosinolates are natural products present in Brassicas, including vegetables such as Brussels sprouts and broccoli. These compounds are currently of great interest due to their apparent anti-cancer activity. Studies have shown that consumption of a diet rich in Brassica vegetables results in lower incidences of certain cancers. Dr Nigel Botting and his team are investigating their bioavailability and metabolism of glucosinolates, in a Food Standards Agency funded project, which involves collaboration with the MacCaulay Institute and the Robert Gordon University in Aberdeen. The St Andrews chemists have synthesised a new isotopically labelled version of two of the most active glucosinolates, glucoraphanin and gluconasturtiin, to allow them to look for metabolites and identify potential new biomarkers of glucosinolate exposure. Read more.
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| Zeolite material exposed to blood |
Nitric oxide is an amazing molecule, with many potential applications in medicine and biology. Unfortunately, as a gas it is difficult to deliver in the right amounts. Prof. Russell Morris and co-workers are developing new zeolites and metal organic frameworks that can be used to store nitric oxide and deliver it to the correct part of the body in the correct dosage. Read more
Research Highlight
Molecules derived from Plants
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| Antibiotics may be derived from daffodils |
Communiqués from the Health Protection Agency frequently draw attention to the worrying growth of antibiotic resistance amongst micro-organisms, and call for the provision of new therapeutic agents to combat this menace. Recent research from the Walton Group, carried out by PhD student Fernando Portela, has shown that dioxime oxalates are particularly clean and atom-efficient sources of iminyl radicals because the only by-product is CO2. The iminyl radicals go on to yield dihydropyrrole or phenanthridine derivatives, depending on the details of their structure. This is a new way of making antibiotics that is safe and more energy efficient. Trisphaeridine, for example, is an alkaloid originally isolated from plants of the Amarillidaceae family (amaryllis, daffodil) used in folk medicine in Eastern Europe for treating sores and tumors. The research featured on the cover of a recent issue of Tetrahedron (2008, 64, 11908.)
Research Highlight
Discovery Boosts Fight Against Infections
A breakthrough by an international research team led by scientists from the University of St Andrews could help fight deadly bacteria responsible for diseases like meningitis, blood disorders and hospital-acquired infections. The scientists’ discovery of a novel bacterial protein complex may ultimately help in designing drugs to disable pathogens that cause a wide range of serious and common disorders, according to Professor James Naismith of the Centre for Biomolecular Sciences at St Andrews. The research is published in Nature (3rd November). It is a joint effort involving St Andrews and the University of Guelph in Canada.
The research team described the first structure representing a previously unknown class of membrane proteins essential in allowing pathogens to elude host immune defences. This protein – Wza - enables the bacteria to move large, complex sugar-containing molecules called polysaccharides through the cell membrane. Once on the cell surface, these long polymer chains make a protective “coat” against the immune system. Prof Naismith said “This is the most strikingly beautiful structure I have seen in my career – the structure is dramatic and looks like a Greek amphora. It gives us a fascinating insight into this very important process. The structure manages a very difficult trick. Imagine two pieces of water separated by a layer of oil. Normally there is no way to move from one pool to the other, oil and water do not mix. Wza takes the carbohydrate from inside the cell, keeps it very wet and allows it cross the oily outer layer of the bacteria. The key trick is Wza does this without creating a hole in the bacteria.”
Read more about Prof Naismith's research programme
.Research Highlight
Polymer Actuators
| Video of polymer actuator (press play) |
Recently-published work by Dr Richard Baker's group, has used techniques based on Magnetic Resonance Imaging (MRI) to study the movement of water and ions inside a soft actuator device during operation. These techniques involved performing electrochemical experiments in situ within the MRI instrument and allowed the team to map changes in chemical environment, concentration and diffusion coefficient of water molecules in working actuators. Soft actuators are devices constructed of polymer or gel materials that are able to undergo dramatic and reversible shape deformation in response to the application of an electrical potential. We worked with soft actuators made from elements of an ionic polymer — Li+-exchanged Nafion -—soaked with water and coated with high surface area metal electrodes on opposite faces. Such devices are known as Ionic Polymer-Metal Composites (IPMCs) and are of great scientific and technological interest because of their unique properties and wide range of potential applications in medical, mechanical, electrical and aerospace engineering. These include their use in artificial valves and muscle in medicine and in the manipulation of fragile objects in robotics and in MEMS devices.
The work is published in J Phys Chem and Soft Matter, or you can read a summary.
Read more about Dr Baker's research programme
.Research Highlight
Ion-channel acts like a camera iris
| Video of mechanosensitive channel (press play) |
Recently-published work by a group led by Jim Naismith and Professor Ian Booth (Aberdeen), has studied an ion channel in E. coli. When E. coli (and other bacteria) move into a region of low osmotic pressure, they feel pressures at their membranes of up to 14 atm. The mechanosensitive channel, MscS, opens to allow rapid ion and water efflux, relieving the turgor pressure that would otherwise destroy the cell. In essence, this is a safety valve for bacteria. The work reveals that MscS opens like a camera iris to create a channel of 13 angstroms. This channel allows water and ions to flood out, decreasing the pressure, and then closes. The valve has to be closed under normal conditions otherwise the cell contents would be lost and the bacteria die. A structure and site directed mutagenesis shows how the protein senses the pressure and adapts its structure.
The work is published in Science.
Read more about Prof Naismith's research programme .
