From Achiral Molecular Components to Chiral Supermolecules and Supercoil Self-Assembly

Yang, Wensheng; Chai, Xiangdong; Chi, Lifeng; Li, Xudong; Cao, Y. Charles; Lu, Ran; Jiang, Yinshan; Tang, Xinyi; Fuchs, Harald; Li, Tiejin

doi:10.1002/(sici)1521-3765(19990401)5:4<1144::aid-chem1144>3.3.co;2-b

Cited by 27 publications

(39 citation statements)

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“…Many of the homochiral supramolecular helical structures that have been described were created through the self‐assembly of chiral molecules and polymers 2. A few reports on the preparation of artificial homochiral helices from achiral components also exist 3. The generation of double‐helical architectures retains a unique fascination, as life itself is encoded within a double‐helical structure.…”

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confidence: 99%

Molecular and Supramolecular Homochirality: Enantiopure Perfluorocarbon Rotamers and Halogen‐Bonded Fluorous Double Helices

et al. 2006

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The beautiful examples of helical structures provided by nature have inspired huge efforts in the generation of synthetic helical assemblies.[1] Many of the homochiral supramolecular helical structures that have been described were created through the self-assembly of chiral molecules and polymers.[2] A few reports on the preparation of artificial homochiral helices from achiral components also exist.[3] The generation of double-helical architectures retains a unique fascination, as life itself is encoded within a double-helical structure. Both metal-ion coordination [4] and hydrogen bonding [5] are well-established agents for the self-assembly of double helices.Herein, we demonstrate how halogen bonding (XB) [6] directs the self-assembly of naked halide anions and longchain diiodoperfluoroalkanes (diiodo-PFAs), leading to the formation of a new type of artificial molecular double helix. In the homochiral supramolecular complex 4 (Figure 1), the perfluorinated module 3 exclusively adopts a right-handed (P) helical conformation (molecular chirality), which translates into chiral and enantiopure fluorous [7] double helices (supramolecular chirality), owing to strong and directional I À ···IÀC halogen bonding.Naked halide anions function as particularly effective halogen-bond acceptors.[8] Ternary mixtures of calixcrownarenes, KI, and diiodo-PFAs give supramolecular complexes in which the calixarene modules complex the K + ions, and the naked I À ions assemble the diiodo-PFAs into infinite fluorous halogen-bonded chains, which segregate the calixarene domains.[8e]We chose 4-tert-butylcalix[4]arenetetra-N,Ndiethylacetamide (1) for its ability to coordinate alkali and alkaline-earth metal cations, and to form separated ion pairs. Interestingly, calixarene 1 forms a supramolecular complex with KI that is characterized by a columnar stacking of 1&K + supercations intercalated by naked I À ions; this arrangement leaves voids parallel to the stacking direction.[9a] When 1 is combined with a divalent cation in 1&Sr(Pic) 2 (Pic = picrate), Figure 1. Structural formulas of the individual components 1-3, and a section of the crystal structure of the supramolecular complex 4. Hydrogen atoms and water molecules are omitted for clarity.

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confidence: 99%

Molecular and Supramolecular Homochirality: Enantiopure Perfluorocarbon Rotamers and Halogen‐Bonded Fluorous Double Helices

et al. 2006

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“…In the UV-vis spectra, a peak band is observed at 460 nm with a shoulder at 485 nm. The peak band at 460 nm can be assigned to the H-aggregation of BA and the shoulder at 485 nm is ascribed to the intermolecular charge trans- These changes confirmed that the hydrogen bonds have been formed between BA and melamine [14].…”

Section: Surface Pressure-area (π -A) Isothermsmentioning

confidence: 62%

“…It has been reported that supermolecules of barbituric acid and melamine in solution can form nanorods, nanofibers and helical structures [14,28,29,34]. We have reported that spiral architectures could be formed by BA itself on the water surface.…”

Section: Afm Of the Ba-m Lb Filmsmentioning

confidence: 87%

“…In a supramolecular level, the chirality of the whole system can be formed not only by the chiral molecules but also by the chiral building block in the system [6,7]. One extreme case is that achiral molecules could assemble into chiral supramolecular assemblies in an aggregate in solution [8,9], in crystals [10], in the Langmuir films [11], and in supramolecular assemblies [12][13][14]. This case is very important because it may relate to the origin of the chirality and even the origin of life.…”

Section: Introductionmentioning

confidence: 99%

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Supramolecular chirality of the hydrogen-bonded complex Langmuir–Blodgett film of achiral barbituric acid and melamine

Huang

Jiang

et al. 2005

Journal of Colloid and Interface Science

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“…In recent decades, great interest has been focused on exploring and extending the chirality by helical polymers [1][2][3] and supramolecular assemblies, [4][5][6][7][8] because these systems can be applied to developing novel chiroptical devices and chiral materials as enantioselective catalysts. [9][10][11][12] On the other hand, the oxazoline derivatives have attracted much attention because of their proved utility in different chemical fields, for example, in asymmetric catalysis, [13][14][15][16][17] supramolecular system, 18,19 and the synthesis of optically active compounds.…”

Section: Introductionmentioning

confidence: 99%

Metal‐induced supramolecular chirality in optically active polymers of oxazoline‐substituted N‐phenylmaleimides

Xi¹,

Jiang²,

Sun³

2007

Chirality

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Polymerization of N-phenylmaleimide derivatives bearing a chiral oxazoline substituent at ortho-position on the phenyl group (namely, N-[o-(4,5-dihydro-1,3-oxazol-2-yl)phenyl]maleimides, OPMI) was carried out with diethylzinc (Et2Zn) as an initiator. The resulting polymers exhibited a quite high specific rotation and a unique split-type circular dichroism. Furthermore, an induced Cotton effect was observed in the pi-pi* transition region of the chromophores upon complexation of these polymers with copper(II) salt in tetrahydrofuran solution, indicating the formation of chiral supramolecular aggregates. The induced supramolecular chirality was found to be dependent on the absolute configuration of monomer units, that is, the polymers with (R)-configurational oxazolinyl chromophores tended to form chiral aggregates with levorotatory handedness, while polymers obtained from the (S)-monomer offered dextrogyrate one upon the addition of Cu(II) salt.

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From Achiral Molecular Components to Chiral Supermolecules and Supercoil Self-Assembly

Cited by 27 publications

References 0 publications

Molecular and Supramolecular Homochirality: Enantiopure Perfluorocarbon Rotamers and Halogen‐Bonded Fluorous Double Helices

Molecular and Supramolecular Homochirality: Enantiopure Perfluorocarbon Rotamers and Halogen‐Bonded Fluorous Double Helices

Supramolecular chirality of the hydrogen-bonded complex Langmuir–Blodgett film of achiral barbituric acid and melamine

Metal‐induced supramolecular chirality in optically active polymers of oxazoline‐substituted N‐phenylmaleimides

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