Chemistry PhD: Heteroborolediides: A New Class of Donor-Acceptor Ligand.

Cyclopentadienyl ligands and their derivatives are ubiquitous to modern organometallic and coordination chemistry, their ease of derivatisation offering a facile means of controlling steric and electronic profiles, thus rendering them key tools for moderating metal reactivity. Currently topical in this respect are ‘hetero-Cp’ ligands, based on replacement of one or more ‘CH’ units with a heteroatom; these are isoelectronic with Cp^–, but exhibit distinctive donor/acceptor properties. Prominent examples include phospholides ([P_nC_5-nH_5-n]^–), which show enhanced p-acceptance relative to Cp^– and are suited to stabilising metals in low-oxidation states. Somewhat less studied are borolediides ([BC₄R₄]^2-), which combine enhanced s-donor and p-acceptor character relative to Cp^–, but also represent an appreciable synthetic challenge. Heteroborolediides represent an attractive, but entirely unexplored, extension to this field, both in terms of achieving nuanced control of ligand character, and the potential for hetero-atom stabilisation enabling more facile synthesis.

This project, funded by the Leverhulme Trust, will build on our recent report of the first diphosphaborolediide, [C₆H₄P₂BPh]^2- (1^2-; Chem. Eur. J. 2021, 27, 16342) to develop this new class of ligand. Initial targets will include developing the coordination chemistry of 1^2- and its complexes, and establishing the generality of the synthetic approach for allowing variation of ligand substituents. Subsequently, modified synthetic routes will be developed to enable wider variations of these substituents, along with the supporting aromatic scaffold and ultimately the nature of the heteroatoms.           

The project will involve substantial anaerobic synthesis, with extensive ‘hands-on’ use of advanced multinuclear NMR spectroscopic techniques as a primary means of compound characterisation and reaction monitoring, augmented by use of Sussex’s state-of-the-art X-ray diffraction facility. There will also be the opportunity, aligned with project need and interest, to learn and use electrochemical (CV, spectro-electrochemistry) and DFT techniques. 

How to apply:

Please submit a formal application using the online system at www.sussex.ac.uk/study/phd/apply attaching a CV, degree transcripts and certificates, statement of interest and two academic references. No research proposal required.

On the application system select Programme of Study – PhD Chemistry, and a January start date. Please ensure you state the project title under funding obtained and include the proposed supervisor’s name where required.

Ideal candidates will have a strong interest in synthetic inorganic / organometallic chemistry and/or ligand design.  

Eligible applicants will hold or be about to obtain a minimum 2:1 honours degree (or equivalent) in chemistry. Candidates for whom English is not their first language will require an IELTS score of 6.5 overall, with not less than 6.0 in any section.

Applications are particularly welcomed from candidates with protected characteristics – e.g., from Black and other ethnic minorities who are under-represented in postgraduate research at our institution.

For enquiries about the project, contact supervisor: i.crossley@sussex.ac.uk attaching a copy of your CV.

For more information on the Crossley Lab see: http://www.sussex.ac.uk/lifesci/crossleylab