Molecular Technology for Chirality Control: From Structure to Circular Polarization

Chirality control is significantly important as one of the molecular technologies; molecular chirality affects both light propagation behaviors and intermolecular interactions in the molecular materials. This chapter introduces the molecular technologies of the fabrication of molecules, molecular aggregations, and nanostructures, those of the detection of circularly polarized luminescence (CPL), circular dichroism (CD), magnetic CPL, and magnetic CD. There are several kinds of sources of circularly polarized light: chiral molecules, materials in a magnetic field, chirality of molecular aggregates, and two-dimensional chirality of nanostructures. The optical activity of the larger chiral materials has been experimentally investigated by measuring changes in macroscopic polarization, which is classically done by CD spectrometer for molecules. Molecular chirality can directly induce CD and CPL. However, there is no still rational strategy to design chiral lanthanide(III) complexes achieving excellent CPL performance due to the lack of conventionally accepted theory to rationalize the CPL activity of lanthanide(III).