Mechanism of diastereoisomer-induced chirality of BiOBr.

Kun Ding,Lu Han,Yingying Duan,Jing Ai,Shunai Che,Zhibei Qu

doi:10.1039/d1sc05601h

Kun Ding, Lu Han + Show 4 more

Open Access

https://doi.org/10.1039/d1sc05601h

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Abstract

Chiral molecule-driven asymmetric structures are known to be elusive because of the intriguing chirality transfer from chiral molecules to achiral species. Here, we found that the chiral assembly of BiOBr is independent of the chirality of the organic molecular inducer but dependent on geometric structural matching between the inducer and inorganic species. Diastereoisomeric sugar alcohols (DSAs) with identical numbers of carbon chiral centers and functional groups but with different R/S configurations and optical activities (OAs) were chosen as symmetry-breaking agents for inducing chiral mesostructured BiOBr films (CMBFs) under hydrothermal conditions. Multiple levels of chirality with different handedness were identified in the CMBFs. Density functional theory (DFT) calculations and molecular dynamics (MD) simulations suggest that asymmetric defects in the Br–Bi tetragonal cone caused by physically adsorbed DSAs on the surfaces of the BiOBr crystals are the geometric basis for triggering the chiral twist in the BiOBr monolayer. Our findings provide new insights for understanding the origin of chirality and the chiral transfer mechanism underlying the assembly of achiral species.

Highlights

Density functional theory (DFT) calculations and molecular dynamics (MD) simulations suggest that asymmetric defects in the Br–Bi tetragonal cone caused by physically adsorbed Diastereoisomeric sugar alcohols (DSAs) on the surfaces of the BiOBr crystals are the geometric basis for triggering the chiral twist in the BiOBr monolayer
The DSAs in the chiral mesostructured BiOBr films (CMBFs) were completely removed by several washes
Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, solid-state 13C CP/MAS NMR spectroscopy (Fig. S4 and S5†), and thermogravimetric analysis (TG) curves (Fig. S6†) indicate that the surfaces of the CMBFs are free of chiral ligands

Summary

Introduction

Chiral molecule-driven asymmetric structures are ubiquitous in biological organisms[1,2,3] and have been arti cially mimicked to fabricate chiral materials, including organics,[4,5,6,7,8,9] inorganics,[10,11,12,13,14,15,16] and organic–inorganic hybrids.[17,18,19] The great potential of assembled chiral inorganics in optics, electricity, magnetism, biology, and chemistry has attracted tremendous interest in the chiral molecule-driven assembly of chiral inorganic nanostructures.[20,21,22,23,24] the chemical and physical chirality origins of inorganic nanostructures involving chiral crystal surfaces,[25,26,27,28] screw dislocation,[29,30,31] chiral imprinting,[32,33] and chiral geometries and assemblies induced by chemisorbed chiral molecules have been proposed,[13,14,15,34,35] chirality transfer from the molecular level to the macroscopic level of inorganic nanostructures across nanometers, micrometers and beyond is still not well understood.[36]. Multiple levels of chirality with different handedness were identified in the CMBFs. Density functional theory (DFT) calculations and molecular dynamics (MD) simulations suggest that asymmetric defects in the Br–Bi tetragonal cone caused by physically adsorbed DSAs on the surfaces of the BiOBr crystals are the geometric basis for triggering the chiral twist in the BiOBr monolayer.

Results

Conclusion