2015 saw many interesting breakthroughs in chemistry and materials science. Here, we report some of the most relevant scientific breakthroughs, including antibiotics from dirt, a catalyst to deactivate chemical weapons, a new solar cell material, and two-dimensional boron.
A New Antibiotic
Probably the most significant 2015 discovery is the development of a new antibiotic, the first one in 30 years, teixobactin. Scientists produced the antibiotic by growing a new bacterium in soil; this microorganism produced several chemical compounds, including teixobactin.
Teixobactin showed powerful activity towards several Gram-positive strains, including Staphylcoccus aureus, which is sometimes resistant to other antibiotics. Teixobactin, however, is not effective towards Gram-negative strains.
This discovery was important also for the technology employed. Researchers employed a new tool called the iChip in the growth and identification of the bacterium which produced teixobactin; this is much more sensitive than similar tools used before. This makes scientists hope that they will be able to identify more antibacterial compounds in the future, using the same technique.
Deactivating Chemical Weapons
Scientists from Northwestern University (US) developed a new catalyst which showed very good activity in deactivating chemical weapons, such as nerve gas agents. The catalyst is a metal-organic framework (MOF) molecule based on zirconium (Zr); in fact, it is made of the organic frame MOF-808, containing 6 connected Zr nodes.
Researchers tested the material on dimethyl 4-nitrophenyl phosphate (DMNP), a harmless molecule which has a similar reactivity to nerve gas (i.e. sarin and tabun). Results showed that the Zr-based catalysts converted DMNP into non-toxic phosphate compounds faster than any other MOF materials tested before; moreover, the catalyst could be used more than once without losing its activity.
This catalyst could be used in protective clothing for military deployed in dangerous areas, as well as in the controlled disposal of chemical weapons.
Iron Dye-based Solar Cells
2015 saw important progress in the field of renewable energy; Swedish scientists developed a potential new solar cell material, which is cheaper and has a smaller impact on the environment. The new material is made of a thin coating of nanostructured titanium dioxide (TiO2) combined with an iron-containing dye – an iron-nitrogen-heterocyclic-carbene complex. This dye replaced conventional dyes used in these types of systems, which are normally based on ruthenium, a much rarer and more expensive element.
The iron-based complex showed high efficiency in harvesting the light and converting it into electrons; this was due to the long life-time of the complex in the excited state.
Although the system is not ready yet to be commercialized (it needs further improvement), it opened a new door for solar cells materials based on iron and/or cheaper and more abundant elements.
Progress in Green Chemistry
Scientists from Colorado State University (US) prepared a new plastic material which is completely recyclable. They made poly-γ-butyrolactone, a polymer prepared through the polymerization of the monomer γ-butyrolactone; this result was very surprising since scientists thought it was not possible to polymerize this monomer.
This new polymer follows several green chemistry principles, since it is made from bioderived materials (i.e. from renewable sources, not derived from fossil fuels) and it can be prepared in mild conditions, using an appropriate catalyst. Moreover, this plastic is completely recyclable. In fact, researchers saw that by treating the polymer at a temperature between 220 and 300 oC, it is completely converted back into the monomer. This means that there are no polymer wastes to pollute the environment and that the monomer can be reused; both these factors lead to a smaller impact on the environment.
New 2-D Materials and Blackest Ever Material
Other interesting news from 2015 include the development of new two-dimensional (2D) materials, and the blackest material ever made.
More specifically, a 2D sheet of boron was made for the first time, within a research project which saw several US universities involved. The material, called borophene, is made of an atom-thin layer of boron. Researchers in a joint project between US and Chinese universities, on the other hand, synthesized for the first time a 2-D layer made of tin; the material is called stanene.
Scientists are interested in 2-D materials since they sometimes show different properties if compared with the corresponding 3-D materials. In the case of borophene, for instance, the 2-D boron layer shows some metallic properties, even if bulk or nanoscale boron behaves as a non-metal.
The blackest ever material was also reported; scientists from KAUST university (Saudi Arabia) synthesized a material which absorbs any light hitting it almost completely (between 98 and 99 %). This is the closest researchers have come to obtaining the ideal black body material, which aborbs 100 % of any incident light radiation.
More Developments Coming
This highlight of 2015 discoveries, although not complete, gives an idea of the importance of chemistry and materials science research in many fields, such as medicine, energy, defense, etc.
Surely, 2016 will give further developments in these areas, with new interesting breakthroughs and/or optimization of the compounds already existing.
Decoding Science. One article at a time.