Sensitised luminescence from phenanthridine appended lanthanide complexes:analysis of triplet mediated energy transfer processes in terbium, europium and neodymium complexes

Time resolved luminescence spectroscopy and laser flash photolysis have bee n used to probe the energy transfer processes in the europium, neodymium an d terbium complexes of ligand, 1. The ligand, chosen because of the high ki netic stability of lanthanide complexes derived from amide-functionalised a zamacrocycles, bears a phenanthridine chromophore that absorbs light at 355 nm, and which can be protonated at low pH. We show that triplet mediated e nergy transfer to the metal centre occurs in the protonated complexes.