Title
Tempo-spatial chirogenesis. Limonene-induced mirror symmetry breaking of Sisingle bondSi bond polymers during aggregation in chiral fluidic media
Author
Michiya Fujiki, Keisuke Yoshida, Nozomu Suzuki, Nor Azura Abdul Rahim, Jalilah Abd Jalil
Year
2016
Journal
Journal of Photochemistry and Photobiology A: Chemistry
Abstract
Herein, we designed photoluminescent polymer aggregates surrounded by organic media containing (S)-/(R)-limonene and (1S)-/(1R)-α-pinene as an artificial model of an open-flow cell-wall free coacervate in a fluidic medium in the ground and photoexcited states. The aggregates were build-up of stiff circular dichroism (CD)-silent and circularly polarized luminescence (CPL)-silent bis(p-n-butylphenyl)polysilanes, nBuPS, and four other diarylpolysilanes. (S)- and (R)-limonene induced more efficiently to their chirality tonBuPS during aggregation, as proven by CD and CPL spectral analysis, compared to (1S)- and (1R)-α-pinene. The nBuPS aggregates generated in a mixture of limonene, methanol, and chloroform had a dissymmetry factor (gabs) as high as +0.04 for (R)-limonene and −0.03 for (S)-limonene at the first Cotton band and a weak dissymmetry factor (glum) of +0.004 for (R)-limonene and −0.003 for (S)-limonene. The gabs factor, however, greatly depended on the volume fraction and chirality of limonene in the tersolvents. These behaviors were ascribed to the tempo-spatial stability and instability of the aggregates suspension in the fluidic media, as revealed by time-course dynamic light scattering measurement.
Instrument
J-725
Keywords
Circular dichroism, Aggregation, Stereochemistry, Circularly polarized luminescence, Polymers