Molecular Architecture towards Helical Double‐Stranded Polymers

Yang, Hui‐Chun; Lin, Shu‐Wha; Yang, Hsiao-Ching; Lin, Cheng-Lan; Tsai, Lun; Huang, Shou‐Ling; Chen, I. Wen-Peter; Chen, Chun‐Hsien; Jin, Bih‐Yaw; Luh, Tien‐Yau

doi:10.1002/anie.200503406

Cited by 101 publications

(23 citation statements)

References 48 publications

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“…[3] As described previously, [3,4] the ferrocene moiety is employed as a linker for these double-stranded polymers because the spacing occupied by the ferrocene moiety appears to be within the limit of span for the vinylcyclopentane monomeric unit in polynorbornenes (5)(6). [3,4,51,52] It has certain rigidity but is also somewhat flexible to accommodate the pending norbornene moieties in 3 in close proximity for the polymerization process. In addition, it may serve as a kind of stuffing to prop up the two polymeric backbones.…”

Section: Resultsmentioning

confidence: 98%

“…[4] Isotacticity and trans double bonds of the backbones [51,54] were adopted for the modeling. The groups of carboxy and methyl ester on the cyclopentadienyl moieties are anti relative to the ferrocene moiety.…”

Section: Resultsmentioning

confidence: 99%

“…[3][4][5]50] Such extraordinary long features were previously ascribed to those significantly deviated from the average molecular weight. [3,4] These oligobisnorbornenes are prepared from a Grubbs I catalyst-mediated ring-opening metathesis polymerization (ROMP). [56,57] Depending on the quenching reagent, some of the terminal groups of the oligoAbstract: Self-assembly at the molecular level in solutions or on a surface is a subject of current interest.…”

Section: Introductionmentioning

confidence: 97%

“…[4,54,55] However, it is puzzling that submicron-long strings are sometimes observed from dropcast films. [3][4][5]50] Such extraordinary long features were previously ascribed to those significantly deviated from the average molecular weight. [3,4] These oligobisnorbornenes are prepared from a Grubbs I catalyst-mediated ring-opening metathesis polymerization (ROMP).…”

Section: Introductionmentioning

confidence: 98%

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Oligomeric Tectonics: Supramolecular Assembly of Double‐Stranded Oligobisnorbornene through π–π Stacking

Lee

Lin

Liao

et al. 2009

Chemistry A European J

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Self-assembly at the molecular level in solutions or on a surface is a subject of current interest. Herein we describe the tailoring of oligobisnorbornene 1, which represents an innovative concept of a preorganized building block on the tens of nanometer scale. The rodlike 1 has vinyl and styrenyl end groups. Scanning tunneling microscopy (STM) reveals that the oligomers aggregate anisotropically along the long axis and form a one-dimensional assembly in which, remarkably, no interstitial gap appears between neighboring oligomers. Dynamic light-scattering (DLS) measurements indicate that the assembly develops in solution. With a shear treatment for dropcast films, a unidirectionally ordered domain with a defect density less than 0.5 % can be prepared. Simulation results by molecular dynamics suggest that there may be multiple interactions such as pi-pi stacking and dipolar attractions taking place between the termini of the oligomers. To demonstrate the importance of double bonds in the oligomeric backbones and termini towards the tectonic assembly, a hydrogenated analogue was synthesized; pi-pi interactions are thus less significant and the film morphology is completely different from that of 1. This work extends the concept of molecular tectonics to preorganized oligomers and opens up a new avenue of nanopatterning toward nanodevices.

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 98%

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Oligomeric Tectonics: Supramolecular Assembly of Double‐Stranded Oligobisnorbornene through π–π Stacking

Lee

Lin

Liao

et al. 2009

Chemistry A European J

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“…Site specific control by a chiral auxilliary at the terminal position is known to induce helical chirality . We recently reported a series of covalently linked, DNA‐like double‐stranded symmetrical ladderphanes 1 by ring opening metathesis polymerization of the corresponding bisnorbornene derivatives 2 . In addition to three dimensional organic or organometallic linkers, a range of different oligoaryls has been used to connect two strands into ladder‐like polymers.…”

Section: Introductionmentioning

confidence: 99%

Double‐stranded ladderphanes with C₂‐symmetric planar chiral ferrocene linkers

Zhang

Liu

et al. 2017

J. Polym. Sci. Part A: Polym. Chem.

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Eight ladderphanes with C 2 -symmetric planar chiral ferrocene linkers are synthesized by ring opening metathesis polymerization of bisnorbornene monomers using Grubbs-I catalyst. The aminobenzoate in both monomers and polymers shows absorption maximum around 320 nm. Both monomers and polymers are Circular dichroism (CD) active. Little enhancements of CD profiles around 320 nm are observed for ladderphanes having chiral chloro-or phenyl-substituted ferrocene linkers. However, ladderphanes with a phenyl substituent on the cyclopendienyl ring exhibits enhancement of CD curves aound 240-300 nm. The congested phenyl moieties in adjacent linkers in this polymer might be well oriented such that interactions between these aromatic substituents on different monomeric units might provoke the enhancement of the CD curves in this region. When the methyl-substituted cyclopendienyl ligand is used for chiral ferrocene linkers, the ladderphanes exhibit two-fold enhancement of CD spectrum around 320 nm. This enhancement is further increased when the cyclopentadienyl ligand contains an additional phenyl substituent, owing to exciton coupling between aminobenzoate moieties in adjacent monomeric units. Moreover, the intensity of the CD curves in the region of 240-300 nm is significantly increased. These results suggest that the later polymer may adopt a posible helical structure.

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