Water-soluble Ir(III) complexes of deprotonated N-methylbipyridinium ligands: fluorine-free blue emitters

New blue or blue-green emitting iridium complexes have been synthesised with cyclometalating ligands derived from the 1-methyl-3-(2'-pyridyl) pyridinium cation. Efficient luminescence is observed in MeCN or aqueous solutions, with a large range of lifetimes in the mu s region and relatively high quantum yields.