Luminescent neutral lanthanide complexes of 5-aryl-2,2′-bipyridine-6-carboxylic acids, synthesis and properties

Phosphorescent lanthanide complexes of 4-aryl-1-(2-pyridyl)-6,7-dihydro-5H-cyclopenta[c]pyridine-3-carboxylic acids and 5-tolyl-2,2′-bipyridine-6-carboxylic acid were prepared. The ligands were synthesized using the “1,2,4-triazine” methodology. In one case, the opportunity for copper complex preparation, followed by exchange of the metal cation from copper to europium to overcome synthetic difficulties, was demonstrated. The ability of tuning the properties of the complexes by means of varying the structure of the ligands was demonstrated. In particular, the introduction of the cyclopentene moiety allowed the preparation of highly soluble complexes in non-polar organic solvents.126