Diamond Concise Annual Review 2019/20

D I A M O N D L I G H T S O U R C E A N N U A L R E V I E W 2 0 1 9 / 2 0 D I A M O N D L I G H T S O U R C E A N N U A L R E V I E W 2 0 1 9 / 2 0 22 23 Crystallography Group T he Crystallography Science Group comprises the High-Resolution Powder Diffraction beamline (I11), the Extreme Conditions beamline (I15), the X-ray Pair Distribution Function (XPDF) beamline (I15-1), and the Small-Molecule Single-Crystal Diffraction beamline (I19) and gathers Diamond’s technical and scientific expertise in crystallography together. This provides a powerful platform for future development and pioneering experiments. The group’s beamlines use various techniques to study structural properties of crystalline, amorphous, and liquid materials in different conditions. These powerful facilities are used in a wide range of science disciplines, including Condensed Matter Physics, Chemistry, Engineering, Earth and Materials, and Life Sciences. Studies in the past year have included new insights into deep Earthminerology, and pioneering developments in the industrial uses of nanoparticles and nanocages. Understanding the Earth’s carbon cycle Synchotron technology is providing new insights on the mechanisms of the carbon cycle. It is known that active plate tectonics plays a key role in producing and sustaining the Earth’s environment. The global carbon cycle transports carbon into Earth’s deep interior by subduction of the carbonate-rich oceanic crust and removes carbon from the atmosphere allowing life to flourish. Although much carbon is re-released as carbon dioxide by volcanic activity, there is some evidence that crustal carbonate can reach the deep mantle and become stored as ‘super- deep diamonds’. However, knowledge of the minerology of carbonated rocks in the mantle is extremely limited. A team of researchers from the University of Bristol exposed carbonate rocks to extreme high temperature (2200K) and pressure (up to 90 GPa) reproducing the conditions of the Earth’s deep interior to see what minerals are formed. Angle dispersive synchrotron X-ray diffraction (XRD) measurements were made on beamline I15, where reaction products were identified from their crystalline Bragg diffraction peaks. The study showed that subduction does not take place further than 1000- 1500 km (halfway to the core-mantle boundary). At these depths, carbonate in a subducted slab reacts with surrounding silica to form minerals and solid carbon dioxide. As the slab temperature increases, the carbon dioxide releases pure carbon, which forms ‘super-deep diamonds’ which may be stored in the deep Earth over geological time-scales representing a long-term sink of carbon before eventually returning to the surface via upwelling mantle plumes. Drewitt JWE et al . doi: 10.1016/j.epsl.2019.01.041 Understanding the actions of nanoparticles Nanoparticlesinliquidsuspensionsarevaluableinmanyindustrialapplications. Previous research has shown that liquid molecules group themselves around a nanoparticle like a shell. These ‘hydration’ shells were known to have 3-5 layers but were not fully understood. A research team from the University of Bayreuth in Germany used X-ray diffraction techniques on Diamond’s I15-1 beamline to analyse the molecular structures of layers associated with magnetic nanoparticles that are used for targeted drug release and imaging. Using the pair distribution function (PDF) technique, the team determined the relationships between nanoparticles and surrounding liquid down to the atomic level. Their results show that the crystalline structure of the nanoparticle has a significant influence on the realignment of nearby water molecules – some molecules adhere to nanoparticles through dissociative bonds and others by molecular adsorption. This new knowledge may help improve the self-assembly of nanoparticles and drive understanding of nanoparticles in the liquid environment. Thom ä SLJ et al . doi:10.1038/s41467-019-09007-1 Breakthrough in nanocage development Nanocages are complex, functional structures with nanometre-sized cavities. They already have a range of applications in chemistry, medicine and environmental science. Numerous research teams have been studying large molecules with an inner cavity that can host a smaller ‘guest’ molecule. The nature of the host can modify the properties of the guest molecule – for example, neutralising an explosive compound. Although a wide range of host molecules have been investigated, until now none have been made using cyclic‘antiaromatic’ molecules which are unusually unstable and difficult to isolate. Researchers working in the Nitschke group at the University of Cambridge synthesised a host species from antiaromatic compounds in order to study the properties of ‘guests’ nesting inside the unusual nanospace. Using X-ray crystallography on the Small Molecule Single Crystal Diffraction beamline l19, they were able to determine the structure of the new host. Their work demonstrated the construction of an anti-aromatic-walled nanospace within a self-assembled nanocage which is the first of its kind. The study also demonstrated the magnetic effects on guests nesting inside this nanospace. Further work is nowneeded to fully understand and exploit any potential applications. Yamashina M et al . doi:10.1038/s41586-019-1661-x