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Linkage control between molecular and supramolecular chirality in 2₁-helical hydrogen-bonded networks using achiral components.

Sasaki T, Hisaki I, Miyano T, Tohnai N, Morimoto K, Sato H, Tsuzuki S, Miyata M - Nat Commun (2013)

Bottom Line: The mechanism of the handedness selectivity or switching phenomenon remains ambiguous, and most phenomena are observed by chance.Here we demonstrate the construction of chiral hydrogen-bonded twofold helical assemblies with controlled handedness in the crystalline state based on crystallographic studies.This study clearly reveals a connection between molecular chirality and supramolecular chirality in the crystalline state.

View Article: PubMed Central - PubMed

Affiliation: Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.

ABSTRACT
Chiral molecules preferentially form one-handed supramolecular assemblies that reflect the absolute configuration of the molecules. Under specific conditions, however, the opposite-handed supramolecular assemblies are also obtained because of flexibility in the bond length and reversibility of non-covalent interactions. The mechanism of the handedness selectivity or switching phenomenon remains ambiguous, and most phenomena are observed by chance. Here we demonstrate the construction of chiral hydrogen-bonded twofold helical assemblies with controlled handedness in the crystalline state based on crystallographic studies. Detailed investigation of the obtained crystal structures enabled us to clarify the mechanism, and the handedness of the supramolecular chirality was successfully controlled by exploiting achiral factors. This study clearly reveals a connection between molecular chirality and supramolecular chirality in the crystalline state.

No MeSH data available.


Related in: MedlinePlus

Enantiomeric and diastereomeric linkages between molecular chirality and supramolecular chirality.(a, i) Enantiomeric linkage in the hydrogen-bonding networks of A(2-o)–B(2-o), and (ii) pseudo-diastereomeric linkage in the hydrogen-bonding networks of A(2-o)–A(1) and A(2-o)–A(2-p). (b) Enantiomeric and diastereomeric linkages in the hydrogen-bonding networks of A(4-p)-c, A(4-p)-t, B(4-p)-c and B(4-p)-t, in which four diastereomeric linkages between molecular chirality and supramolecular chirality are observed.
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f3: Enantiomeric and diastereomeric linkages between molecular chirality and supramolecular chirality.(a, i) Enantiomeric linkage in the hydrogen-bonding networks of A(2-o)–B(2-o), and (ii) pseudo-diastereomeric linkage in the hydrogen-bonding networks of A(2-o)–A(1) and A(2-o)–A(2-p). (b) Enantiomeric and diastereomeric linkages in the hydrogen-bonding networks of A(4-p)-c, A(4-p)-t, B(4-p)-c and B(4-p)-t, in which four diastereomeric linkages between molecular chirality and supramolecular chirality are observed.

Mentions: All the resulting single crystals belong to chiral space groups and have 1D ladder-type HB networks with 21-helicity. The handedness of the 21-helicity was determined using the supramolecular tilt chirality method (Fig. 2b, inset (iii)) and is listed in Table 1, where right- or left-handedness of the SMC is symbolized as supP or supM, respectively, along with absolute configurations (that is, R and S) of the amines. First, we ascertained the usual enantiomeric relationship of the helical HB networks using A- and B-salts with methylbenzoic acid (2). The crystals of A(2-o) and B(2-o) belong to the monoclinic C2 space group. A(2-o) with (R)-isomers display R-supP, whereas B(2-o) with (S)-isomers is S-supM, as expected (Fig. 3a(i)). Non- and para-substituted acids introduced a drastic change; the crystals of A(1) and A(2-p) belong to the orthorhombic P212121 space group and are R-supM, in contrast to the R-supP structure of A(2-o) (Fig. 3a(ii)). This pair of supramolecules can be regarded as pseudo-diastereomers.


Linkage control between molecular and supramolecular chirality in 2₁-helical hydrogen-bonded networks using achiral components.

Sasaki T, Hisaki I, Miyano T, Tohnai N, Morimoto K, Sato H, Tsuzuki S, Miyata M - Nat Commun (2013)

Enantiomeric and diastereomeric linkages between molecular chirality and supramolecular chirality.(a, i) Enantiomeric linkage in the hydrogen-bonding networks of A(2-o)–B(2-o), and (ii) pseudo-diastereomeric linkage in the hydrogen-bonding networks of A(2-o)–A(1) and A(2-o)–A(2-p). (b) Enantiomeric and diastereomeric linkages in the hydrogen-bonding networks of A(4-p)-c, A(4-p)-t, B(4-p)-c and B(4-p)-t, in which four diastereomeric linkages between molecular chirality and supramolecular chirality are observed.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3644081&req=5

f3: Enantiomeric and diastereomeric linkages between molecular chirality and supramolecular chirality.(a, i) Enantiomeric linkage in the hydrogen-bonding networks of A(2-o)–B(2-o), and (ii) pseudo-diastereomeric linkage in the hydrogen-bonding networks of A(2-o)–A(1) and A(2-o)–A(2-p). (b) Enantiomeric and diastereomeric linkages in the hydrogen-bonding networks of A(4-p)-c, A(4-p)-t, B(4-p)-c and B(4-p)-t, in which four diastereomeric linkages between molecular chirality and supramolecular chirality are observed.
Mentions: All the resulting single crystals belong to chiral space groups and have 1D ladder-type HB networks with 21-helicity. The handedness of the 21-helicity was determined using the supramolecular tilt chirality method (Fig. 2b, inset (iii)) and is listed in Table 1, where right- or left-handedness of the SMC is symbolized as supP or supM, respectively, along with absolute configurations (that is, R and S) of the amines. First, we ascertained the usual enantiomeric relationship of the helical HB networks using A- and B-salts with methylbenzoic acid (2). The crystals of A(2-o) and B(2-o) belong to the monoclinic C2 space group. A(2-o) with (R)-isomers display R-supP, whereas B(2-o) with (S)-isomers is S-supM, as expected (Fig. 3a(i)). Non- and para-substituted acids introduced a drastic change; the crystals of A(1) and A(2-p) belong to the orthorhombic P212121 space group and are R-supM, in contrast to the R-supP structure of A(2-o) (Fig. 3a(ii)). This pair of supramolecules can be regarded as pseudo-diastereomers.

Bottom Line: The mechanism of the handedness selectivity or switching phenomenon remains ambiguous, and most phenomena are observed by chance.Here we demonstrate the construction of chiral hydrogen-bonded twofold helical assemblies with controlled handedness in the crystalline state based on crystallographic studies.This study clearly reveals a connection between molecular chirality and supramolecular chirality in the crystalline state.

View Article: PubMed Central - PubMed

Affiliation: Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.

ABSTRACT
Chiral molecules preferentially form one-handed supramolecular assemblies that reflect the absolute configuration of the molecules. Under specific conditions, however, the opposite-handed supramolecular assemblies are also obtained because of flexibility in the bond length and reversibility of non-covalent interactions. The mechanism of the handedness selectivity or switching phenomenon remains ambiguous, and most phenomena are observed by chance. Here we demonstrate the construction of chiral hydrogen-bonded twofold helical assemblies with controlled handedness in the crystalline state based on crystallographic studies. Detailed investigation of the obtained crystal structures enabled us to clarify the mechanism, and the handedness of the supramolecular chirality was successfully controlled by exploiting achiral factors. This study clearly reveals a connection between molecular chirality and supramolecular chirality in the crystalline state.

No MeSH data available.


Related in: MedlinePlus