1. a School of Chemistry , University of Birmingham , Edgbaston, Birmingham, B15 2TT, UK
2. b Institut des Sciences Moléculaires, CNRS UMR 5255, Université Bordeaux 1 , 33405, Talence, France
3. c School of Biosciences, University of Birmingham , Edgbaston, Birmingham, B15 2TT, UK
4. d Henry Wellcome Building for Biomolecular NMR Spectroscopy , School of Cancer Sciences, University of Birmingham , Edgbaston, Birmingham, B15 2TT, UK
5. e Chemistry Department , University of Warwick , Gibbet Hill Road, Coventry, CV4 7AL, UK
6. f School of Chemistry and Chemical Engineering, Queen's University (QUB) , David Keir Building, Stranmillis Road, Belfast, BT9 5AG, UK