Lanthanide complexes as smart CD probes for chirality sensing of biological substrates

Lanthanide tris(beta-diketonates) and porphyrinates acted as effective circ ular dichroism (CD) probes for chirality sensing of neutral and zwitterioni c guests. They were electrically neutralized but formed highly coordinated 1 :1 complexes with various guests. When a chiral, non-chromophoric guest w as combined with a chromophoric lanthanide probe, the resulting highly coor dinated complex exhibited characteristic CD signal, the sign of which was d ependent on the absolute configuration of the bound guest. Since there are wide variations of coordinating ligands and lanthanide centers, lanthanide coordination chemistry offers great possibilities for the design of new CD chirality sensory systems especially for biologically important guests.