Optical activity of SiC nanoparticles prepared from single-handed helical 4,4′-biphenylene-bridged polybissilsesquioxane nanotubes

Abstract

Single-handed helical SiC/C nanotubes were prepared by the carbothermal reduction of single-handed helical 4,4′-biphenylene-bridged polybissilsesquioxane nanotubes which were prepared through a supramolecular templating approach using a pair of enantiomers. The walls were constructed from amorphous carbon randomly doped with SiC nanoparticles. Circular dichroism (CD) spectra indicated that the optical activity mainly originated from the carbonaceous framework. Optically active SiC nanoparticles were obtained after calcining the SiC/C nanotubes in air. The CD spectrum of the SiC nanoparticles was simulated using time-dependent density functional theory. Their optical activity was proposed to originate from chiral defects. The chiral SiC nanoparticles imparted their single-handedness on the poly(n-nonyl-2-methylpropylsilane) main chain.