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Updated: Jun 9, 2025
Line Shape Analysis of Dynamic NMR Spectra for Characterizing Coordination Sphere Rearrangements at a Chiral Rhenium Polyhydride Complex
Published on: July 27, 2022
Nanoscale chirality generated in zinc(II) orthophosphate clusters: evidence by vibrational circular dichroism
Sumio Aisawa1, Nami Horiguchi1, Chika Chida1
1Faculty of Science and Engineering, Iwate University, 4-3-5 Ueda, Morioka, Iwate, 020-8551, Japan. aisawa@iwate-u.ac.jp.
Abstract:
Layered zinc(II) hydroxides (LZH) intercalating the deprotonated forms of R-(-) or S-(+)-1,1'-binaphthyl-2,2'-diyl hydrogenphosphate (denoted as R- or S-BNDHPH, respectively) were prepared from Zn(NO3)2 at pH 5 and 60 °C by the mixing method. The obtained hybrid compounds (denoted as R- or S-BNDHP-/LZH, respectively) were heated from room temperature up to 800 °C under nitrogen atmosphere. According to the thermal gravimetric/differential thermal analysis measurements, hydroxyl groups were dehydrated at 270-400 °C, followed by the decomposition of organic components at 420-600 °C. X-ray diffraction patterns and scanning electron microscopy images indicated that the final products were a mixture of α-Zn3(PO4)2, ZnO crystals and non-crystalline zinc(II) orthophosphates. Vibrational circular dichroism (VCD) spectra were recorded before and after calcination. Before calcination, R- or S-BNDHP-/LZH exhibited VCD peaks assigned to intercalated R- or S-BNDHP-. The calcined products exhibited several VCD peaks in the range of 900-1200 cm-1, maintaining the mirror-image relationship between R-BNDHP-/LZH and S-BNDHP-/LZH used as starting materials. The observed peaks were assigned to the PO (symmetric), -POO-, and PO (asymmetric) stretching vibrations of the PO43- groups. According to theoretical simulations, the observed VCD activity can be rationalised in terms of vibrational coupling between two PO43- groups in a generated chiral zinc(II) orthophosphate cluster.
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