Rotational dynamics in molecular crystals influence not only internal structures but also bulk properties such as photophysical behavior.In this work,we present novel crystalline chiral binuclear N-heterocyclic carben...Rotational dynamics in molecular crystals influence not only internal structures but also bulk properties such as photophysical behavior.In this work,we present novel crystalline chiral binuclear N-heterocyclic carbene(NHC)Au(I)complexes,1-R and 1-S,which display a distinct axially chiral conformation with C_(2)-symmetry,derived from non-equivalent orientations of phenyl groups on the NHC ligands.These phenyl moieties undergo two distinct types of rapid rotational motion,as revealed by variable-temperature solid-state^(2)H NMR studies.Such dynamic motions promote structural symmetrization within the crystal,shifting from C_(2)-symmetry toward a more D_(2)-like symmetry.This symmetry evolution significantly affects the chiroptical properties of the crystals.Both experimental measurements and TD-DFT calculations confirm that such motion modulates chiroptical properties,leading to temperature-dependent changes in emission intensity and the luminescence dissymmetry factor(g_(lum)).These results highlight dynamic molecular rotation as a powerful tool for tuning symmetry and chiroptical responses in crystalline materials,offering new design principles for solid-state chiral systems.展开更多
基金supported by the Japan Society for the Pro-motion of Science(JSPS)via KAKENHI grants JP20H04666,JP21K14637,JP22K18333,JP22H00318 and JP25K23603by the JST via CREST grant JPMJCR19R1+1 种基金by FOREST grant JPMJFR232Cby the Institute for Chemical Reaction Design and Discovery(ICReDD)established by the World Premier International Research Initiative(WPI),MEXT,Japan.
文摘Rotational dynamics in molecular crystals influence not only internal structures but also bulk properties such as photophysical behavior.In this work,we present novel crystalline chiral binuclear N-heterocyclic carbene(NHC)Au(I)complexes,1-R and 1-S,which display a distinct axially chiral conformation with C_(2)-symmetry,derived from non-equivalent orientations of phenyl groups on the NHC ligands.These phenyl moieties undergo two distinct types of rapid rotational motion,as revealed by variable-temperature solid-state^(2)H NMR studies.Such dynamic motions promote structural symmetrization within the crystal,shifting from C_(2)-symmetry toward a more D_(2)-like symmetry.This symmetry evolution significantly affects the chiroptical properties of the crystals.Both experimental measurements and TD-DFT calculations confirm that such motion modulates chiroptical properties,leading to temperature-dependent changes in emission intensity and the luminescence dissymmetry factor(g_(lum)).These results highlight dynamic molecular rotation as a powerful tool for tuning symmetry and chiroptical responses in crystalline materials,offering new design principles for solid-state chiral systems.
