Study of chiral imaging sensors using induced circularly polarized luminescence from rare earth complexe

Induced circularly polarized luminescence （iCPL) from emitting probe molecules has been studied for the structure of the probes and environment around the complex. Rare-earth complexes such as [Eu（pda)2]-（pda = 1,10 phenanthroline 2,9 dicarboxylic acid) have been selected as the probes due to their high emissive properties and relatively large g values, and its achiral structures. When the rare-earth complexes exhibit CPL in spite of their achiral structures, the observation will mean that the structure of the complex is distorted to chiral by other chiral molecules or environments. This type of iCPL is available for chiral sensing system. The CPL sensing system has a potential to be employed in a microscopic sensing system with high sensitivity, and a single molecule CPL spectroscopy. In this view point, we have searched achiral emissive rare earth complexes which are likely distorted to chiral structure and show strong CPL signal when they sense chiral molecules or environments. We found [Eu（pda)2]-and [Eu（bda)2]-（bda = 2,2'-bipyridine-6,6'-dicarboxic acid) exhibits intense iCPL by some amino acids such as S（R)-2-Pyrrolidone-5-Carboxylic acid in aqueous solution. Furthermore, we have examined iCPL detection via microscopic system and made iCPL mapping for a conjugatedsystem using [Eu（pda)2]-as a iCPL probe molecule.