Conformational analysis of dipeptide‐derived polyisocyanides

Cornelissen, Jeroen J. L. M.; Graswinckel, W.S.; Rowan, Alan E.; Sommerdijk, Nico A. J. M.; Nolte, Roeland J. M.

doi:10.1002/pola.10713

Cited by 49 publications

(46 citation statements)

References 34 publications

(60 reference statements)

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“…These CD spectra are similar to those measured for polyisocyanides derived from a-alanine dipeptides, confirming that the amide groups in a hydrogen bond have a similar effect on the n-p* transitions of the imine chromophores. [23] In contrast to polyisocyano-a-alaninepeptides, the assumed right-handed or P screw sense results in a negative Cotton effect and the magnitude of the effect is smaller. The first observation can be tentatively rationalized by the opposite direction of the first amide group, whereas the smaller magnitude is likely caused by the larger distance to the polymer backbone as is clear from the schematic representation in Figure 5.…”

Section: Resultsmentioning

confidence: 96%

Synthesis, Characterization, and Folding Behavior of β‐Amino Acid Derived Polyisocyanides

Wezenberg

Metselaar

Rowan

et al. 2006

Chemistry A European J

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Helical polymers of isocyanopeptides derived from beta-amino acids have been synthesized and their architectures have been studied in detail. Similar to their alpha-amino acid analogues, the helical conformation in these macromolecules is stabilized by internal hydrogen-bonding arrays along the polymeric backbone. Unexpectedly, the flexibility of the beta-peptide side arms results in a rearrangement of the initial macromolecular architecture, leading to a more stable helical structure possessing a better defined hydrogen-bonding pattern, as was concluded from IR and temperature-dependent circular dichroism studies. Based on these results we propose a dynamic helical model for the beta-amino acid derived polyisocyanopeptides; this model is in contrast to the kinetically stable helical macromolecules that are formed upon polymerization of alpha-amino acid based isocyanopeptides.

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Section: Resultsmentioning

confidence: 96%

Synthesis, Characterization, and Folding Behavior of β‐Amino Acid Derived Polyisocyanides

Wezenberg

Metselaar

Rowan

et al. 2006

Chemistry A European J

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“…[12] As a consequence, the 4 1 helical conformation, which is generally presumed to be present in the polyisocyanide architectures, is probably a 39 10 helical conformation for polyisocyanodipeptides LL-PIAA and LD-PIAA. In related polymers containing porphyrin-functionalized alanines as side chains, an angle of 228 was found between repeat units n and (n + 4).…”

Section: Resultsmentioning

confidence: 99%

“…It is assumed that this ordering of amides locally creates a large permanent dipole which greatly influences the n-p* transitions of the imine chromophores. [12] The influence of the amide groups on the circular dichroic absorption of the imines enables one to study the hydrogenbonding behavior of the polymers by using the imine chromophores as so-called "spectator groups" for the amide functions closest to the polymer backbone. Figure 3a shows a strong difference in intensity of the Cotton effect around l = 310 nm between the three different diastereomeric polyisocyanotripeptides prepared at room temperature.…”

Section: Resultsmentioning

confidence: 99%

Polyisocyanides Derived from Tripeptides of Alanine

Metselaar

Adams

Nolte

et al. 2007

Chemistry A European J

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Helical polymers of isocyanotripeptides derived from alanine have been synthesized and their architectures studied in detail. The helical conformation of the polyisocyanotripeptides is stabilized by internal hydrogen-bonding arrays between the tripeptide side chains. The possibility of extending the well-defined hydrogen-bonded array, from dipeptide to tripeptide side chains, depends strongly on the stereochemistry of the constituent alanine amino acids, as has been shown by circular dichroism and IR studies. In polymers containing a weaker hydrogen-bonding array adjacent to the polymer backbone, due to steric interactions between the alanine methyl groups, a stronger second hydrogen-bonding array was present between the peptide bonds furthest away from the main chain, which is probably a result of stretching/compression of the helical-polymer conformation.

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“…[11][12][13] On the basis of molecular modeling, vibrational circular dichroism (CD) and solid-state nuclear magnetic resonance (NMR) analyses, a main chain of polyisocyanopeptides is predicted to form an ∼ 4/1 helical conformation, in which four repeating units constitute one helical turn and the helical handedness is dependent on the chirality of amino acid residues as pendant groups. 12,14,15 In addition, polyisocyanopeptides bearing electronically or optically functionalized pendants have great potential to be promising electron-, hole-or energy-transporting materials because of their densely packed pendant array.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of polyisocyanides bearing oligothiophene pendants: higher-order structural control through pendant framework design

Ikai

Takagi

Shinohara

et al. 2015

Polym J

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L-Alanine-based polyisocyanides bearing oligothiophene (OT) pendants (poly-3a and poly-3b) were synthesized and the influence of the OT pendants on the chiroptical properties and helix-forming abilities of the polymers was investigated. Poly-3a bearing a quinquethiophene unit with two n-hexyl chains successfully formed a preferred-handed helical conformation by simultaneous interactions of the OT-pendant π-π stacking and hydrogen bonding of the amide groups. In contrast, poly-3b, which possesses a branched alkyl chain on behalf of the terminal n-hexyl chain of poly-3a, did not form a higher-ordered helical conformation. The results suggest that the structure of the alkyl chains positioned far from the polymer backbones remotely and sensitively affected the ability of the polymer to form a helical conformation. We also found that the structure of the OT pendants significantly affect the molecular weight as observed by AFM measurements. The polyisocyanide poly-3c bearing a bithiophene unit was additionally synthesized to examine the influence of the number of thiophene rings within the OT pendants on the higher-order structure formation.

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Conformational analysis of dipeptide‐derived polyisocyanides

Cited by 49 publications

References 34 publications

Synthesis, Characterization, and Folding Behavior of β‐Amino Acid Derived Polyisocyanides

Synthesis, Characterization, and Folding Behavior of β‐Amino Acid Derived Polyisocyanides

Polyisocyanides Derived from Tripeptides of Alanine

Synthesis of polyisocyanides bearing oligothiophene pendants: higher-order structural control through pendant framework design

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