Chiral Template-Driven Macroscopic Chirality Control: Structure-Second-Harmonic Generation Properties Relationship

Abstract

Chirality is one of the most important topics in chemistry attributable to the peculiar stereochemical properties. Since the chirality belongs to one of the noncentrosymmetric (NCS) crystal classes, chiral materials may reveal second-harmonic generation (SHG) properties, one of the unique structure-related properties. The high efficiency of SHG can be achieved by the well-controlled alignment of NCS chromophores such as d(0) transition metal cations in distorted octahedra, lone pair cations, highly polarizable d(10) cations, pi-delocalized anionic groups, etc. Chiral organic structure-directing agents can also serve as chiral templates by aligning inorganic units in hybrid solid-state materials. In this Minireview, recently reported ten chiral materials containing both chiral templates and SHG active unsymmetrical metal cations are introduced. The relationship between the asymmetric arrangement of the NCS chromophores achieved by the interaction with chiral templates and the resulting SHG properties are investigated, which might provide further insight for designing novel chiral materials.