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 d0 transition metal cations in distorted octahedra, lone pair cations, highly polarizable d10 cations, π‐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.

1D Chiral Lead Halide Perovskites with Superior Second‐Order Optical Nonlinearity

“…Such an outstanding SHG effect that is significantly larger than our previous work and other chiral hybrid perovskites (Table S4, Supporting Information), even among the highest in the whole hybrid perovskite materials to our knowledge. [ 45,46 ] These results suggest that ( R/S ‐2‐MPD)PbBr 3 crystals have high‐performance second‐order NLO properties which make it promising candidate for NLO applications.…”

“…[ 43,44 ] In particular, chiral halide perovskites serve as ideal candidates for SHG because of their asymmetric structures to meet the requirements for second‐order optical nonlinearity. [ 45–47 ] However, although several chiral perovskite crystals have been reported to exhibit SHG responses, [ 13,48–51 ] it remains very challenging to fabricate hybrid perovskites for practical NLO applications featuring simultaneously large SHG coefficient, good optical transparency, high laser damage thresholds (LDT), and stable physical and chemical properties. [ 52,53 ] In this work, we have constructed a series of chiral lead halide hybrid perovskites ( R/S ‐2‐MPD)PbX 3 (X = Cl, Br, I), templated by 2‐methylpiperidine enantiomers ( R/S ‐2‐MPD).…”

(R)- and (S)-[C8H10NO3]2[NbOF5]: noncentrosymmetric niobium oxyfluorides with large optical anisotropy

“…[30][31][32] Recently, our group has been quite successful in systematically synthesizing a series of novel NCS organic-inorganic hybrid materials or coordination compounds by utilizing chiral structure-directing agents or chiral ligands. [33][34][35][36][37] We found that the crystals exhibit large birefringence (Δn exp ) of 0.19-0.199@589.3 nm; thus, the origin of the large optical anisotropy is elucidated through a more detailed analysis. The newly synthesized materials also exhibit large band gaps along with strong stability in various solvents.…”

Methylpiperazine based 0D chiral hybrid lead halides for second harmonic generation

“…27,28 Furthermore, HOMHs can obtain chiral properties to feature unique properties such as CD, CPL, ferroelectricity, piezoelectricity, pyroelectricity, spin-optoelectronics and NLO properties. 18,21,[28][29][30][31][32][33][34] Billing et al firstly incorporated the S-MBA (MBA, methylbenzylammonium) chiral ligands into lead-based HOMHs to synthesize the first 1D chain crystal. 35,36 Our group has explored the second-order NLO properties of 2D chiral HOMHs R-MPEA (MPEA, methylphenethylamine) based on lead 37 and some environmentally friendly metals such as Sn 38 and Cu(I).…”