From In Situ Crystal Seed Generation to Chirality Control: Stage-Specific Irradiation by Plasmon-Coupled Circularly Polarized Light and High Enantioselectivity

The synergy between localized surface plasmon resonance
(LSPR)
of nanoparticles and circularly polarized light (CPL) is expected
to achieve enantiocontrol by amplifying the chiral electromagnetic
field of CPL. In prior studies, through the combination of highly
focused CPL via optical tweezers and lithographic LSPR-active nanostructures,
full-time irradiation in chiral crystallization enabled enantiocontrol,
with a crystal enantiomeric excess (CEE) reaching 56%. To explore
a more feasible and effective strategy, we developed a two-stage crystallization
approach for NaClO3 and tetraphenylethylene (TPE), where
plasmon-coupled CPL was applied exclusively for in situ crystal seed
generation. High enantioselectivity was achieved: 79–100% CEE
for NaClO3, and 52% and −44% batch-to-batch enantioselectivity
for TPE, implicating a nucleation-governed and seed-amplification
mechanism for the enantiocontrol of CPL. Meanwhile, chemically synthesized
nanoparticles and direct CPL irradiation (for TPE) were employed,
suggesting an easier protocol. This work provides a practical and
efficient enantiocontrol strategy driven by plasmon-coupled CPL, with
the advantages of minimal CPL irradiation and a simplified plasmonic
optical setup.