Scheme: University Research Fellowship
Organisation: University of Southampton
Dates: May 2013-Jun 2016
Summary: Solid state nuclear magnetic resonance (ssNMR) is a viable tool to study structural properties of materials and to have insight on the local environment of the nuclei at the molecular level.
My research focuses on development of methods for ssNMR as well as applications to materials. In particular we develop methods for the observation of nitrogen-14 (14N), which is the most abundant isotope of nitrogen but is not often the target for NMR investigation because of the challenges arising from the fact that 14N has a quadrupole moment, and that can cause severe difficulties for signal detection. We work on development of methods in this area with the goal to ease the study of the nitrogen environment without the need of costly isotopic labelling. This is a significant advantage for natural materials and drugs. Even though is fairly easy to achieve isotopic labelling of protein samples, 14N NMR can provide more details insight into the structure and dynamics of the materials.
My main area of interest, when it comes to applications of solid state NMR are (1) superconductors, and (2) catalysis.
1) Superconductors are materials which do not have resistance to DC currents below the so-called critical temperature (often well below 100 K). We have prepared fulleride-based superconductors in which the fullerene molecules host inside their cage a single hydrogen or water molecule. Cryogenic NMR revealed that the endohedral molecule display a very different behaviour from the atoms on and outside the cage, which puzzled many specialists in the field. A theoretical explanation for this is still missing.
For another superconductor, magnesium diboride, we explored the NMR properties of the carbon doped species, which has particularly favourable properties for industrial applications. Carbon-13 NMR revealed that carbon atoms replace individual boron atoms and do not cluster. This was an open question for researchers in the field.
Dates: Oct 2007-Apr 2013
Summary: My research is in the field of solid state nuclear magnetic resonance (NMR), with attention to magic-angle spinning (MAS). MAS improves resolution and signal intensity by means of rotating the sample at high speeds (many kHz) with a tilt angle of 54.74 degrees with respect to the main magnetic field. NMR can be very informative even when dealing with powders and amorphous materials. Long range order is not a requirement.
My research targets in this field are materials where potential applications are more than plausible.
My group has pioneered the work on cryogenic MAS on superconductors. Superconductors are materials which have no resistance to DC currents below their critical temperature. Hence, when single cristals are unavailable, to get valuable high resolution data by NMR, it is essentail to spin the sample at low temperature (often well below -150C). We have now published a proof-of-concept study in this field and we are expanding to new research targets, with particular attention to new superconducting materials and to materials where applications already exist.
Much of the solid state NMR with involves high resolution studies of nitrogen involves exchanging the naturally abundant nitrogen-14 (14N) isotope with the rare (and expensive) nitrogen-15 (15N) isotope. 15N is spin 1/2 hence it is much easier to and has much narrower lines. 14N on the other hand has spin 1 and it possesses a quadrupole moment which leads to line broadening and many other technical issues. In the last few years indirect detection of 14N has been revived and we are contributing to this field by developing new methods for more efficient detection of this isotope. Among the applications there are natural biomolecules as well as natural products, where spin labelling is not straighforward.
Recent work involves collaborations with groups studying materials of direct impact to society, including catalysts (Beckmann rearrangement, step in nylon production) and resins for coating boats