Lignins are amongst the most abundant biopolymers on Earth, and are key components of the cell walls of many vascular plants. However, our fundamental knowledge of the photochemistry of the molecular building blocks that make up lignins (i.e. the monolignols, p-coumaryl, coniferyl and sinapyl alcohols) is currently limited. In this project, we will conduct novel experiments to explore the basic electronic spectroscopy and photochemical properties of key monolignols. Experiments will be performed on isolated gas-phase molecules, free from the influences of the other components in the complex native plant environment. In particular, we propose to investigate the key question of how the UV properties of monolignols are affected if the molecule is neutral, protonated or deprotonated. This critical issue has been almost entirely ignored to date, despite the fact that lignols exist in aqueous environments, where protonation state can vary. Data will be obtained for the uncharged lignols initially using two-colour photoionization spectroscopy (MCRC group). These results will then be directly compared against photodissociation spectra obtained using laser-interfaced electrospray mass spectrometer (CED group), where the monolignol molecules can be produced in their protonated/deprotonated forms in the gas phase. The mass selectivity allows potentially for laser bandwidth limited UV spectra to be recorded not only of the protonated/deprotonated molecule but also any photoproducts. Further experiments will be conducted on aggregates of the lignols (both neutral and ionic), involving pairs of lignols and also lignol-water molecule complexes to perform the first molecular-level investigations of how the UV properties evolve upon aggregation and also microsolvation. The availability of experimental systems for obtaining the gas-phase UV laser spectra of both neutral and charged lignol species within a single department is unique to York, and therefore offers a prime opportunity to perform internationally-leading measurements in this emerging field.
The project will provide very broad training opportunities in a range of highly-transferrable skills including mass spectrometry, (soft ionization techniques, CID, and mass spectral analysis), and laser spectroscopy (use of class 4 laser systems). Training will also be offered in computational chemistry techniques (ab initio and DFT) to support the interpretation of experimental results. The Dessent/Cockett research groups foster a lively scientific environment for students, with regular group meetings, directed literature reading, close links to the other internal and external research groups, rapid publication of post-graduate results and attendance at external UK and international scientific meetings.
All Chemistry research students have access to our innovative Doctoral Training in Chemistry (iDTC): cohort-based training to support the development of scientific, transferable and employability skills: https://www.york.ac.uk/chemistry/postgraduate/idtc/.
The Department of Chemistry holds an Athena SWAN Gold Award and is committed to supporting equality and diversity for all staff and students. The Department strives to provide a working environment which allows all staff and students to contribute fully, to flourish, and to excel: https://www.york.ac.uk/chemistry/ed/.
This project is available to students from any country who can fund their own studies. The Department of Chemistry at the University of York is pleased to offer Wild Fund Scholarships. Applications are welcomed from those who meet the PhD entry criteria from any country outside the UK. Scholarships will be awarded on supervisor support, academic merit, country of origin, expressed financial need and departmental strategy. For further details and deadlines, please see our website.
You should expect hold or expect to achieve the equivalent of at least a UK upper second class degree in Chemistry or a related subject. Please check the entry requirements for your country: