Self-directing chiral information in solid–solid transformation: unusual chiral-transfer without racemization from amorphous silica to crystalline silicon

Liu, Xinling; Tsunega, Seiji; Jin, Ren‐Hua

doi:10.1039/c6nh00214e

Cited by 17 publications

(34 citation statements)

References 59 publications

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“…In our recent work, we found that chirality in silica is still retained even after bundles of chiral SiO 2 nanofibres were downscaled into sub‐10 nm SiO 2 nanoparticles. Optical activity manifested through stretching vibrations of Si−O bonds in vibrational circular dichroism (VCD) spectra . The chirality of our SiO 2 nanofibres should be accounted for by the asymmetric arrangement of Si and O atoms in Si−O clusters on the molecular scale .…”

Section: Methodsmentioning

confidence: 99%

“…Optical activity manifested through stretching vibrations of Si−O bonds in vibrational circular dichroism (VCD) spectra . The chirality of our SiO 2 nanofibres should be accounted for by the asymmetric arrangement of Si and O atoms in Si−O clusters on the molecular scale . Therefore, by trapping Eu 3+ (or Tb 3+ ) ions with the eventual formation of Eu 2 O 3 (or Tb 2 O 3 ) nanoparticles in chiral silica matrices, a local chiral environment on the size‐scale less than 10 nm is provided by the surrounding chiral clusters of Si−O linkages.…”

Section: Methodsmentioning

confidence: 99%

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Circularly Polarized Luminescence from Inorganic Materials: Encapsulating Guest Lanthanide Oxides in Chiral Silica Hosts

Sugimoto

Liu

Tsunega

et al. 2018

Chemistry A European J

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Recently, circularly polarized luminescence (CPL)-active systems have become a very hot and interesting subject in chirality- and optics-related areas. The CPL-active systems are usually available by two approaches: covalently combining a luminescent centre to chiral motif or associating the guest of luminescent probe to a chiral host. However, all the chiral components in CPL materials were organic, although the luminescent components were alternatively organics or inorganics. Herein, the first totally inorganic CPL-active system by "luminescent guest-chiral host" strategy is proposed. Luminescent sub-10 nm lanthanide oxides (Eu O or Tb O ) nanoparticles (guests) were encapsulated into chiral non-helical SiO nanofibres (host) through calcination of chiral SiO hybrid nanofibres, trapping Eu (or Tb ). These lanthanide oxides display circular dichroism (CD) optical activity in the ultraviolet wavelength and CPL signals around at 615 nm for Eu and 545 nm for Tb . This work has implications for inorganic-based CPL-active systems by incorporation of various luminescent guests within chiral inorganic hosts.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Circularly Polarized Luminescence from Inorganic Materials: Encapsulating Guest Lanthanide Oxides in Chiral Silica Hosts

Sugimoto

Liu

Tsunega

et al. 2018

Chemistry A European J

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“…As described above, the chirality in silica is exactly based on irregular tetrahedra of SiO 4 throughout the silica network; thus, it would be a good candidate for transferring irregular tetrahedron structures to the reduced silicon. We performed the reduction of d ‐ and l ‐form silica pre‐sintered at 800 °C by Mg powders at 500–600 °C under an Ar atmosphere . The initial nanofibrous morphologies of the silica were completely destroyed after the reduction, whereas the silicon produced showed nanoflake morphology (Figure ).…”

Section: Chiral Silica's Potential As a Chiral Sourcementioning

confidence: 99%

“…We performed the reductiono fd-a nd l-form silica pre-sintered at 800 8Cb yM g powders at 500-600 8Cu nder an Ar atmosphere. [25] The initial nanofibrous morphologies of the silica were completely destroyed after the reduction, whereas the silicon produced showedn anoflake morphology ( Figure 13). As expected, the silicon flakes transformed from d-t ol-silica exhibited remarkable CD signals with am irror relationship in the absorption band of 400-500 nm (Figure 14).…”

Section: Enantiomerically Enriched Asymmetric Silica With Chiropticalmentioning

confidence: 99%

Understanding Silica from the Viewpoint of Asymmetry

Jin

2019

Chemistry A European J

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Silica is abundant in the Earth's crust, and silicate materials are used on the global scale, from industrial products for architecture, vehicles, electronics, and optics to consumption as foods, medicines, supplements, and cosmetics. Silica has become increasingly important in current science and technology, as seen in the components of advanced materials. The characteristic formula of silica is very simply often expressed as SiO2. However, it is difficult to draw silica precisely owing to its intricate chemical structures. We need to make a greater effort in understanding silica, even though silica chemistry has existed for over 200 years. Similar to the homochirality observed in natural amino acids, natural silica of quartz is chiral, and in some sense, the origin of life with chirality might be partly related to quartz‐like silica chirality. This review focuses on the asymmetry of silica from the view of the formation of irregular tetrahedron structures of SiO4. Silica is composed of several repeated tetrahedron units of SiO4, leading to the formation of inorganic polymers with divergently expanded 3D structures. In this large polymeric skeleton, not every unit of SiO4 can maintain an ideal tetrahedron, and thus, it becomes twisted. The twisting results in an asymmetric point on the Si atom, leading silica to become racemic in the stereochemical sense. Therefore, enantioselective preparation of silica should endow silica with chirality through the silica skeleton. Some recent achievements exhibit that silica is an effective chiral material and has great potential for transferring chirality from silica to other matter.

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“…We recently revealed that cluster-like sub-10-nm chiral domains are present in our chiral silica. 22,23 In other words, the chirality would arise from the asymmetric arrangement of Si and O atoms through the nanofibrous silica frames (<10 nm). Although the detailed arrangement of Si and O atoms is still unclear, a certain number of SiO 4 tetrahedrons should arrange into molecular-scale helixes or the SiO 4 tetrahedrons are chirally distorted.…”

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confidence: 99%

Double Chiral Hybrid Materials: Formation of Chiral Phenolic Resins on Polyamine-associated Chiral Silica

et al. 2017

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Chiral SiO 2 nanofibers associated with polyamines on their surfaces could promote polymerization between resorcinol and formaldehyde on silica surface to give phenolic resins (RF). In this process, the chiral information was effectively transferred from SiO 2 to the final phenolic resins forming double chiral hybrid.Keywords: Double chiral hybrid | Chiral SiO 2 nanofiber | Chiral phenolic resinThe synthesis of chiral polymers with optical activity is of major importance because of their great demand in many areas like life sciences, pharmaceuticals, and optics.13 To achieve chirality in polymers during the polymerization process, various chiral sources have been employed for chiral transfer, which includes chiral organometallic complexes catalysts, chiral organic solvents, chiral polymeric templates, and even circular polarized light.4 On the other hand, some inorganic materials (e.g., porous SiO 2 , metal nanoparticles) have been widely used as supports for the load of chiral components to construct various heterogeneous catalysts, which possess advantages like easy separation and recycling of catalysts; however, most of these inorganic supports are achiral. 57 Based on the best of our understanding, to date, there are no reports on chiral polymerization using achiral catalyst supported by chiral inorganic supports.For a long time, the chiral inorganics are less of a concern compared with organics, despite the existence of natural inorganic crystals with intrinsically chiral crystal structures (e.g., quartz) or surfaces (e.g., Pt(643)). 8,9 However, in the past two decades, the research on the chiral transfer between organics and inorganics has gained increasing attention, and a series of synthetic inorganics have been endowed with chirality by molecular imprinting from small chiral organic molecules (on the molecular scale) or by copying the helical shapes (with helical pitch sizes over tens of nanometers) of organic templates.10,11 Interestingly, without the combination of external chiral components, it has been demonstrated that some natural and synthetic chiral inorganics could be directly applied to the enantioselective separation and synthesis of chiral organic small molecules (e.g., amino acids, glucoses).9,1215 Consequently, these achievements have opened a new avenue for chirality transfer from inorganics to organics. Recently, we reported a successful approach for the preparation of carbon nanotubes via carbonization of hybrid nanofibers of phenolic resins-coated silica which were synthesized by polymerization of resorcinol and formaldehyde on the polyamine (catalyst)-associated silica (template and support) nanofibers. 16 On the other hand, we also succeeded in the synthesis of chiral silica promoted by crystalline complexes self-assembled from polyethyleneimine (PEI) and enantiomeric tartaric acid (tart).17 By combining the above two achievements, herein, we attempted the synthesis of chiral phenolic resins (RF) by polymerization of resorcinol (R) and formaldehyde (F), employing the SiO 2 /PEI chi...

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Self-directing chiral information in solid–solid transformation: unusual chiral-transfer without racemization from amorphous silica to crystalline silicon

Abstract: Self-transfer of chiral information was found in the magnesiothermic reduction of amorphous chiral SiO2 nanofibers into crystalline Si.

Cited by 17 publications

References 59 publications

Circularly Polarized Luminescence from Inorganic Materials: Encapsulating Guest Lanthanide Oxides in Chiral Silica Hosts

Circularly Polarized Luminescence from Inorganic Materials: Encapsulating Guest Lanthanide Oxides in Chiral Silica Hosts

Understanding Silica from the Viewpoint of Asymmetry

Double Chiral Hybrid Materials: Formation of Chiral Phenolic Resins on Polyamine-associated Chiral Silica

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