Probing solution behaviour of metallosupramolecular complexes using pyrene fluorescence

A new method for assessing the topology of metallosupramolecular assemblies using pyrene-appended ligands is reported. Two potentially tetradentate ligands containing one (L1) and two (L2) terminal pyrene moieties were synthesised and their complexes with Cu+ and Cd2+ were characterised. Photophysical measurements demonstrate that in [Cu2(L1)2]2+, [CdL1]2+ and [Cu2(L2)2]2+ the emission spectra are dominated by monomeric emission but in the cadmium complex of L2 (where the pyrene units are in close proximity) a quenching of the luminescence coupled with weak emission at 540 nm is indicative of excimer formation.