CCDC 2330325-233033 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing data_request@ccdc.cam.ac.uk, or by contacting the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: + 44 1223 336033. The raw data for all the figures are openly available on Figshare: International Collaboration Grant (EP/Y002695/1, A.F.R.K., T.K.). We acknowledge computational resources and support provided by DJEI/DES/SFI/HEA Irish Centre for High-End Computing (ICHEC). We are grateful to the NMR Facility in the School of Chemistry at the University of Leicester supported by the EPSRC (EP/W02151X/1). X-ray diffraction at the University of Leicester was supported by the EPSRC (EP/V034766/1).