Generation of Supramolecular Chirality around Twofold Rotational or Helical Axes in Crystalline Assemblies of  Achiral Components

Miyata, Mikiji; Tohnai, Norimitsu; Hisaki, Ichiro; Sasaki, Toshiyuki

doi:10.3390/sym7041914

Cited by 36 publications

(39 citation statements)

References 48 publications

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“…Considering the shape of the cluster with protruding aromatic side parts and the lattice parameters, two‐dimensional arrangements of the clusters can be illustrated by in‐plane up and down ABAB order, as reflected in the SAXS pattern (Figure d). Taking into account that the 2D sheets of 1 consist of slipped aromatic chiral clusters with in‐plane up and down AB packing, the in‐plane hydrophilic dendrimer domains formed between the clusters would be alternatively arranged resulting in two different chiral spaces (Figure b) . Accordingly, we envisioned that the hydrophilic domains in an aromatic matrix can play a role as chiral containers for entrapping hydrophobic guests in a hydrophilic solvent, so that the 2D sheet with ordered chiral hydrophilic domains functions as an enantioselectively absorbing 2D material as one enantiomer would bind preferentially to the chiral void spaces …”

Section: Figurementioning

confidence: 99%

“…Taking into account that the 2D sheets of 1 consist of slipped aromatic chiral clusters with in-plane up and down AB packing, the in-plane hydrophilic dendrimer domains formed between the clusters would be alternatively arranged resulting in two different chiral spaces (Figure 4 b). [21] Accordingly, we envisioned that the hydrophilic domains in an aromatic matrix can play a role as chiral containers for entrapping hydrophobic guests in a hydrophilic solvent, so that the 2D sheet with ordered chiral hydrophilic domains functions as an enantioselectively absorbing 2D material as one enantiomer would bind preferentially to the chiral void spaces. [26,27] To explore the capability of the self-assembled sheets for enantioselective absorption, we selected hydrophobically substituted tartrate (G1) because the void space in the aromatic sheet of 1 is bounded by hydrophobic, aromatic interior walls and the in-plane size is roughly compatible with the size of the guest in a folded conformation ( Figures S8 and S11).…”

Section: Zuschriftenmentioning

confidence: 99%

“…We envisioned that, when a rectangular plate-like aromatic building block is face-on grafted with a chiral flexible chain, the aromatic stack would slip in a preferred direction caused by chiral transfer to break mirror symmetry, resulting in a chiral superstructure (Figure 1 b). [21][22][23] In this context, we synthesized a rectangular-shaped, planar aromatic segment with a hydrophilic chiral dendron at the center of the basal plane. The amphiphilic molecule 1 that forms a 2D porous structure consists of a tetrabranched aromatic segment and an internally grafted oligoether dendron.…”

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Single‐Layered Chiral Nanosheets with Dual Chiral Void Spaces for Highly Efficient Enantiomer Absorption

et al. 2020

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Although considerable effort in recent years has been devoted to the development of two‐dimensional nanostructures, single‐layered chiral sheet structures with a lateral assembly of discrete clusters remain elusive. Here, we report single‐layered chiral 2D sheet structures with dual chiral void spaces in which discrete clusters of planar aromatic segments are arranged with in‐plane AB order in aqueous methanol solution. The chirality of the sheet is induced by the slipped‐cofacial stacks of rectangular plate‐like aromatic segments in the discrete clusters which are arranged laterally with up and down packing, resulting in dual chiral void spaces. The chiral nanosheets function as superfast enantiomer separation nanomaterials, which rapidly absorb a single enantiomer from a racemic mixture with greater than 99 % ee.

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Section: Figurementioning

confidence: 99%

Section: Zuschriftenmentioning

confidence: 99%

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confidence: 99%

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Single‐Layered Chiral Nanosheets with Dual Chiral Void Spaces for Highly Efficient Enantiomer Absorption

et al. 2020

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“…This fact brought us a question "what is the origin of chirality in two-fold helix-based crystals?" The supramolecular-tilt-chirality method based on two concepts, tilt chirality and multi-point approximation, answered the question as described below (Figure 1) [22][23][24][25][26]. Inspired by the discovery of hidden chirality in a two-fold helix, we have been seeking for further hidden chirality not only in supermolecules [29] but also in a wide range of materials, including polymers.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Hidden Chirality: Two-Fold Helicity in β-Strands

Sasaki

Miyata

2019

Symmetry

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A β-strand is a component of a β-sheet and is an important structural motif in biomolecules. An α-helix has clear helicity, while chirality of a β-strand had been discussed on the basis of molecular twists generated by forming hydrogen bonds in parallel or non-parallel β-sheets. Herein we describe handedness determination of two-fold helicity in a zig-zag β-strand structure. Left-(M) and right-handedness (P) of the two-fold helicity was defined by application of two concepts: tilt-chirality and multi-point approximation. We call the two-fold helicity in a β-strand, whose handedness has been unrecognized and unclarified, as hidden chirality. Such hidden chirality enables us to clarify precise chiral characteristics of biopolymers. It is also noteworthy that characterization of chirality of high dimensional structures like a β-strand and α-helix, referred to as high dimensional chirality (HDC) in the present study, will contribute to elucidation of the possible origins of chirality and homochirality in nature because such HDC originates from not only asymmetric centers but also conformations in a polypeptide chain.Symmetry 2019, 11, 499 2 of 9 an approximation method of molecules: one-point and multi-point approximation in the former and the latter, respectively. We call the chirality, whose handedness cannot be recognized in a general way by mathematical crystallography but definitely exists in materials, as hidden chirality. Not only clear helices, including three-fold, four-fold, and six-fold helices in crystals as well as α-helices in proteins, but also helices having hidden chirality like two-fold helices, may serve as the origin of chirality [17,18,28].

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“…To understand correlation between molecular structure and molecular aggregation is one of important themes for designing novel organic solid materials and organic molecular crystals. [1][2][3][4][5][6] Crystal engineering often use a concept of supramolecular synthon 7 for leading objective crystal structure. Supramolecular synthons are kinetically defined structural units that transfer the essential features of a crystal structure, and a critical assumption is that the synthon is a reasonable approximation to the whole crystal.…”

Section: Introductionmentioning

confidence: 99%

Dimeric Molecular Aggregation Motif in Crystal of 2,7-Diethoxy-1-(4-Nitrobenzoyl)naphthalene: Correlation of Single Molecular Structure, Molecular Accumulation Structure and Non-Covalent-Bonding Interactions

Ohisa

Saeki

Shiomichi

et al. 2018

ECB

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Crystal structure of 2,7-diethoxy-1-(4-nitrobenzoyl)naphthalene C21H19NO5, is reported and discussed on the characteristics of the spatial organization of single molecule and molecular aggregation as contrasted with a homologous compound. The molecular structures of these compounds differ only in the kind of alkoxy group of 2,7-positions of the naphthalene rings, i.e., ethoxy groups for title compound and methoxy groups for homologue. In single molecular crystal structures of these compounds, 4-nitrobenzoyl group is non-coplanarly attached to the naphthalene ring. The molecules exhibit axial chirality, with either R or S stereogenic axis. The two pairs of the enantiomeric molecules are related by twofold helical axis in the asymmetric unit of P21/n space group for title compound and P21/c one for homologue, showing the number of molecules (Z) is four for both compounds. In their molecular packing structures, (R)-and (S)enantiomers are connected to each other by … stacking interactions, forming centrosymmetric dimeric molecular aggregates. However, the aggregation structures of the dimers are apparently different between title compound and homologue. The dimeric units of title compound are stacked into columnar structure with (sp 2)C-H…O=C non-classical hydrogen bonds between identical enantiomers along aaxis. The columns are connected by (sp 2)C-H…OEt non-classical hydrogen bonds between identical enantiomers along c-axis to give sheet-like aggregation spreading on ac-plane. The sheets are piled up through (sp 3)C-H… non-classical hydrogen bonds between opposite enantiomeric molecules of next dimeric aggregates along b-axis giving layers. On the other hand, the dimeric molecular aggregates of homologue are connected into flattish column by (sp 3)C-H…O=C non-classical hydrogen bonds and (sp 3)C-H… nonclassical hydrogen bonds between identical enantiomers. The columns are linked into waving plate through weak (sp 2)C-H… nonclassical hydrogen bonds. In title compound, difference between … stacking interactions and non-classical hydrogen bonds is smaller than homologue in contribution to the whole of molecular packing structure.

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Generation of Supramolecular Chirality around Twofold Rotational or Helical Axes in Crystalline Assemblies of Achiral Components

Cited by 36 publications

References 48 publications

Single‐Layered Chiral Nanosheets with Dual Chiral Void Spaces for Highly Efficient Enantiomer Absorption

Single‐Layered Chiral Nanosheets with Dual Chiral Void Spaces for Highly Efficient Enantiomer Absorption

Characterization of Hidden Chirality: Two-Fold Helicity in β-Strands

Dimeric Molecular Aggregation Motif in Crystal of 2,7-Diethoxy-1-(4-Nitrobenzoyl)naphthalene: Correlation of Single Molecular Structure, Molecular Accumulation Structure and Non-Covalent-Bonding Interactions

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