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 been used to probe the energy transfer processes in the europium, neodymium and terbium complexes of ligand, 1. The ligand, chosen because of the high kinetic stability of lanthanide complexes derived from amide-functionalised azamacrocycles, bears a phenanthridine chromophore that absorbs light at 355 nm, and which can be protonated at low pH. We show that triplet mediated energy transfer to the metal centre occurs in the protonated complexes.