P NMR chemical shifts are referenced externally to H3PO4 at 0.0 ppm in D2O. CDCl3, C6D6 and THF-d8 were purchased from Eurisotop and used as received. Coupling constants (J) are reported in Hertz (Hz) to the nearest 0.1 Hz. The multiplicity abbreviations used are: s (singlet), d (doublet), t (triplet), q (quartet), m (multiplet), br (broad). GCMS spectra were obtained on an Agilent 7890A GC system coupled to a 5975C inert XL EI/CI MSD triple axis-mass detector. Electron impact (EI) ionisation was utilised, specifically the method EI320-10-1-SPLIT. The column temperature was 320 °C, and the carrier gas was helium with a flow rate of 1 mL/min. GC-FID analyses were carried out using an Agilent 7890A gas chromatograph fitted with an Agilent HP5 column (30 m x 0.25 mm x 0.25 μm). Helium was used as the carrier gas (2.0 mL/min flow rate). The maximum column temperature was 340 °C and the instrument was operated in a splitless mode. UV-visible absorption spectra were recorded at room temperature using an Agilent Cary 60 spectrophotometer. Baseline corrections were achieved by reference to pure solvent. Emission spectra were recorded using a Cary Eclipse spectrometer operating in right-angle geometry mode, and all spectra were fully corrected for the spectral response of the instrument. All solutions used in fluorescence measurements had an absorbance below 0.2 at the excitation wavelength to minimize inner filter, unless stated otherwise. 16