Although most free radical are highly reactive and have very limited lifetime, some possess excellent stability. The magnetic properties of unpaired electron make such radicals promising building blocks for magnetic materials. Stable radicals also find other applications including organic conductors, sensors, antioxidants and polymerisation inhibitors.
There are however very few classes of stable free radicals. The most common stable radicals include nitroxides, triarylmethyls and hydrazyl derivatives. In particular, Blatter’s free radicals which were first reported in 1968, show excellent benchtop stability and are actively investigated for magnetic materials applications. However, functionalisation of Blatter’s radicals is difficult; for instance, the substituents at the C(3) position (shown in blue on the inset) are limited to alkyl, aryl and heteroaryl groups.
We have recently reported an unusual rearrangement of Nitron 1, a commercially available analytical reagent, to form a Blatter’type radical 2 with an amido-substituent at the C(3) position. The amide substituent can be further hydrolysed to yield an amino substituted radical 3. This is an unprecedented substitution pattern for Blatter-type radicals, which opens up many possibilities to develop further derivatives of this stable radical.
This project aims to develop mechanistic understanding of the new rearrangement, and build a structure-reactivity relationship. We will determine the structures of intermediates and by-products of this reaction, and will use quantitative analysis (e.g., reaction kinetics) to analyse substituent effects. The reaction can be conveniently monitored by EPR spectroscopy and other analytical techniques.
We believe that the mechanistic understanding of the new rearrangement will allow us to rationally design new reactions leading to stable radicals, and new substitution patterns for the Blatter-type radicals. For instance, we hypothesise that the rearrangement 1→2 proceeds via a hydrolytic opening of the triazolium ring. Understanding the factors that determine the rate of this, consequent and side reactions will allow us to determine whether similar process can be used to prepare Blatter’s radicals with different substituents at the C(3) position, beyond amino and amido groups.
Apart from the mechanistic study, we will also explore the feasibility of functional group transformations with the derivatives of radical 3, functionalising the exocyclic amino group and investigating other methods to generate Blatter-type radicals with new substituents. The magnetic properties of the new compounds will be characterised using EPR spectroscopy and magnetic measurements.
The project is a collaboration of two supervisors with genuinely complementary research expertise and interests which cover physical organic chemistry, free radical chemistry, EPR spectroscopy.
All research students follow our innovative Doctoral Training in Chemistry (iDTC): cohort-based training to support the development of scientific, transferable and employability skills. All research students take the core training package which provides both a grounding in the skills required for their research, and transferable skills to enhance employability opportunities following graduation. Core training is progressive and takes place at appropriate points throughout a student’s higher degree programme, with the majority of training taking place in Year 1. In conjunction with the Core training, students, in consultation with their supervisor(s), select training related to the area of their research.
The project will be a great opportunity to learn many new techniques. The supervisors will provide extensive training in physical organic chemistry, reaction kinetics and mechanisms. The student will learn to use EPR spectrometers and interpret EPR spectra, and will receive training in synthetic methodology and will have ample opportunities to practice synthetic skills.
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. Chemistry at York was the first academic department in the UK to receive the Athena SWAN Gold award, first attained in 2007 and then renewed in October 2010 and in April 2015.
This project is open to students who can fund their own studies or who have been awarded a scholarship separate from this project. The Chemistry Department at York is pleased to offer Wild Fund Scholarships to those from countries outside the UK. Wild Fund Scholarships offer up to full tuition fees for those from countries from outside the European Union. EU students may also be offered £6,000 per year towards living costs. For further information see: View Website
1. Grant, J. A., Lu, Z. Tucker, D. E., Hockin, B. M., Yufit, D. S., Fox, M. A., Kataky, R., Chechik, V., O'Donoghue, A. C., Nature Comm., 8, 15088 (2017).
2. Bodzioch, A., Zheng, M., Kaszyński P. & Utecht, G. J. Org. Chem. 79, 7294 (2014).
3. Jasiński, M., Szczytko, J., Pociecha, D., Monobe, H. & Kaszyński, P. J. Am. Chem. Soc. 138, 9421 (2016).
How good is research at University of York in Chemistry?
FTE Category A staff submitted: 47.06
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