Amide Conformational Switching Induced by Protonation of Aromatic Substituent

Yamasaki, Ryu; Tanatani, Aya; Azumaya, Isao; Saito, Shôichi; Yamaguchi, Akemi; Kagechika, Hiroyuki

doi:10.1021/ol034344g

Cited by 88 publications

(79 citation statements)

References 17 publications

(9 reference statements)

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“…In fact, prior studies have shown that the bent (E) configuration of the amide becomes more energetically favorable relative to the linear configuration (Z) when the amide is functionalized with alkyl group, thus hindering junction formation. [46][47][48] To further investigate this, we performed DFT calculations (details in ESI †) to determine the structure of our series of molecules in the gas phase and in solution using the SMD solvation model (Density-based Solvation Model). Tetrachloroethene (or perchloroethylene, PCE) was substituted for 1,2,4-trichlorobenzene (TCB) during the solution phase calculations since TCB is not included in Gaussian 09.…”

Section: Resultsmentioning

confidence: 99%

Structure–function relationships in single molecule rectification by N-phenylbenzamide derivatives

et al. 2016

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We examine structure-function relationships in a series of N-phenylbenzamide (NPBA) derivatives by using computational modeling to identify molecular structures that exhibit both rectification and good conductance together with experimental studies of bias-dependent single molecule conductance and rectification behavior using the scanning tunneling microscopy break-junction technique. From a large number of computationally screened molecular diode structures, we have identified NPBA as a promising candidate, relative to the other structures that were screened. We demonstrate experimentally that conductance and rectification are both enhanced by functionalization of the NPBA 4-carboxamido-aniline moiety with electron donating methoxy groups, and are strongly correlated with the energy of the conducting frontier orbital relative to the Fermi level of the gold leads used in break-junction experiments.

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Section: Resultsmentioning

confidence: 99%

Structure–function relationships in single molecule rectification by N-phenylbenzamide derivatives

et al. 2016

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“…The rotational barriers were estimated by the coalescence method, and the results are shown in Table and in the Supporting Information. The rotational barrier of 3 was roughly estimated to be 14.1 kcal mol −1 , which is close to that of N ‐methyl acetanilide ( 2 ), while those of 4 and 5 were decreased to 13.0 and 12.1 kcal mol −1 , respectively. It is noteworthy that the rotational barrier of 5 was comparable to that of N ‐acyl pyrroles and showed a possibility of N ‐alkynyl substituted anilides as a new type of ground‐state‐destabilized amides .…”

Section: Resultsmentioning

confidence: 89%

N‐Ethynylation of Anilides Decreases the Double‐Bond Character of Amide Bond while Retaining trans‐Conformation and Planarity

Yamasaki

Morita

Iizumi

et al. 2019

Chemistry A European J

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Activated amide bonds have been attracting intense attention; however, most of the studied moieties have twisted amide character. To add a new strategy to activate amide bonds while maintaining its planarity, we envisioned the introduction of an alkynyl group on the amide nitrogen to disrupt amide resonance by nN→Csp conjugation. In this context, the conformations and properties of N‐ethynyl‐substituted aromatic amides were investigated by DFT calculations, crystallography, and NMR spectroscopic analysis. In contrast to the cis conformational preference of N‐ethyl‐ and vinyl‐substituted acetanilides, N‐ethynyl‐substituted acetanilide favors the trans conformation in the crystal and in solution. It also has a decreased double bond character of the C(O)−N bond, without twisting of the amide. N‐Ethynyl‐substituted acetanilides undergo selective C(O)−N bond or N−C(sp) bond cleavage reactions and have potential applications as activated amides for coupling reactions or easily cleavable tethers.

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“…The broadening of allyloxy groups were probably due to the steric hindrance caused by N-butylation, which could hinder the rotation around amide linkage. 44,45 To prove this speculation further, the model compound N,N 0 -dibutyl-N,N 0 -diphenyl 2,5-bis(allyloxy) terephthalamide (N-B-CM) was prepared (Scheme 3). It was fully characterized by 1 H/ 13 C NMR (Supporting Information Figs.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and properties of poly(p-phenylene terephthalamide) bearing both polar and unsaturated substituents introduced via claisen rearrangement reaction

Wang

Guan

et al. 2016

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

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A series of novel wholly aromatic copolyamides, poly(p-phenylene terephthalamide)-ran-poly[p-phenylene 2,5-bis(allyloxy)terephthalamide] x (50,5,25, 50, 60, 75, 90, and 100) represents the molar fraction of allyloxy containing structure unit), were prepared via low temperature solution copolycondensation of p-phenylenediamine, terephthaloyl chloride, and 2,5-bis(allyloxy)terephthaloyl chloride. They were converted to the target copolymers, poly(p-phenylene terephthalamide)-ran-poly[p-phenylene 2,5-diallyl23,6-dihydroxyterephthalamide] (CRPPTA-x), through Claisen rearrangement reaction, as characterized by a comprehensive analyses of NMR, FT-IR, gel permeation chromatography, and differential scanning calorimetry. Although APPTA-x had a poor solubility in common organic solvents, the rearranged products with high co-unit contents, that is, CRPPTA-60, 75, 90, and 100, were readily dissolved in m-cresol, DMF, DMAc, DMSO, and NMP. The effect of these four polymers, used as sizing agents, on the interfacial adhesion between Kevlar fiber and epoxy resin was investigated by the contact angle method, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and microbond tests. Compared with the naked fibers, the sized fibers displayed enhanced surface energy and roughness. The fibers sized with 0.5 wt % CRPPTA-60 solution in NMP exhibited a maximum increase of 19% in interfacial shear strength.

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Amide Conformational Switching Induced by Protonation of Aromatic Substituent

Cited by 88 publications

References 17 publications

Structure–function relationships in single molecule rectification by N-phenylbenzamide derivatives

Structure–function relationships in single molecule rectification by N-phenylbenzamide derivatives

N‐Ethynylation of Anilides Decreases the Double‐Bond Character of Amide Bond while Retaining trans‐Conformation and Planarity

Synthesis and properties of poly(p-phenylene terephthalamide) bearing both polar and unsaturated substituents introduced via claisen rearrangement reaction

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