Infrared Studies of the Association of Secondary Amides in Various Solvents

Klemperèr, William; Cronyn, Marshall W.; Maki, August H.; Pimentel, George C.

doi:10.1021/ja01651a091

Cited by 76 publications

(41 citation statements)

References 3 publications

(3 reference statements)

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“…For the solutions of DMAPA in the Amide‐A region (NH stretching vibrations) the IR intensity of the signal attributed to the free amide groups and located in the region of 3426 cm −1 decreases with an increase in monomer concentration, while the intensity of the band located in the region of 3200–3400 cm −1 corresponding to the associated amides was found to increase . The absorption bands attributed to the cyclic dimer and linear associate were found to locate at 3275 cm −1 and 3373 cm −1 correspondingly.…”

Section: Resultsmentioning

confidence: 92%

“…In the Amide‐I region (CO stretching vibrations) a bathochromic shift from 1681 cm −1 (free monomer) to 1668 cm −1 (cyclic dimer) and to 1661 cm −1 (linear associate) caused by H‐bonding between amide molecules was observed . The shift of the absorption maximum in the Amide‐II region (NH bending and CN stretching vibrations) from 1513 (free monomer) to 1546 cm −1 (linear associate) with an increase in amide concentration serves as the evidence of the H‐bond formation …”

Section: Resultsmentioning

confidence: 92%

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Influences of monomer self‐association on the radical solution homopolymerization of N‐[3‐(dimethylamino)propyl](meth)acrylamide

Каморин

Rumyantsev

Казанцев

et al. 2016

J of Applied Polymer Sci

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The specific dependencies of the initial reduced polymerization rate on the initial monomer concentration were introduced for the radical homopolymerization of N‐[3‐(dimethylamino)propyl]acrylamide (DMAPA) and N‐[3‐(dimethylamino)propyl]methacrylamide (DMAPMA) in toluene, DMF, and water at 60 °С. The degree of the monomer self‐association and the ratio of the amides constituting various types of associates were evaluated using FT‐IR spectroscopy and computer simulation for the solutions of DMAPA and DMAPMA in toluene with different monomer concentrations. The hypothesis linking the type of predominant pre‐reaction monomer assemblies and the revealed concentration effects was proposed for the homopolymerization of aminoamide monomers and explaining unconventional experimental data. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44412.

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Section: Resultsmentioning

confidence: 92%

Section: Resultsmentioning

confidence: 92%

Influences of monomer self‐association on the radical solution homopolymerization of N‐[3‐(dimethylamino)propyl](meth)acrylamide

Каморин

Rumyantsev

Казанцев

et al. 2016

J of Applied Polymer Sci

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“…[69][70][71][72] The NH stretch frequency of 3377 cm À1 of monomer 1 lies in the weak bonding regime. 69 The broad width of the N-H stretch also suggests a N-HÁ Á ÁOQC bonding. On the other hand, the amide I stretch frequency of 1683 cm À1 is indicative of a free CQO stretch as is widely seen in the literature.…”

Section: N-há á áOq Q Qc and C-há á áOq Q Qc Hydrogen Bonding With Oxmentioning

confidence: 99%

Hydrogen bonding and chemical shift assignments in carbazole functionalized isocyanides from solid-state NMR and first-principles calculations

Gowda

Vasconcelos

Schwartz

et al. 2011

Phys. Chem. Chem. Phys.

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Carbazole functionalized polyisocyanides are known to exhibit excellent electronic properties (E. Schwartz, et al., Chemistry of Materials, 2010, 22, 2597). The functionalities and properties of such materials crucially depend on the organization and stability of the polymer structure. We combine solid-state Nuclear Magnetic Resonance (NMR) experiments with first-principles calculations of isotropic chemical shifts, within the recently developed converse approach, to rationalize the origin of isotropic chemical shifts in the crystalline monomer l-isocyanoalanine 2-(9H-carbazol-9-yl) ethyl amide (monomer 1) and thereby gain insight into the structural organization of its polymer (polymer 2). The use of state-of-the-art solid-state NMR experiments combined with Density Functional Theory (DFT) based calculations allows an unambiguous assignment of all proton and carbon resonances of the monomer. We were able to identify the structure stabilising interactions in the crystal and understand the influence of the molecular packing in the crystal structure on the chemical shift data observed in the NMR spectra. Here the Nuclear Independent Chemical Shift (NICS) approach allows discriminating between 'physical' interactions amongst neighboring molecules such as ring-current effects and 'chemical' interactions such as hydrogen bonding. This analysis reveals that the isocyanide monomer is stabilized by multiple hydrogen bonds such as a bifurcated hydrogen bond involving -N-H, -C-H and O=C- moieties and Ar-H···C≡N- hydrogen bonding (Ar = aromatic group). Based on the geometrical arrangement it is postulated that the carbazole units are involved in the weak σ-π interactions giving rise to a Herringbone packing of the molecules. The chemical shift analysis of the polymer spectra readily establishes the existence of N-H···O=C hydrogen bonds despite the limited resolution exhibited by the polymer spectra. It is also elucidated that the relative arrangement of the carbazole units in the polymer differs significantly from that of the monomer.

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“…As CH 2 Cl 2 has sufficient solubility in peptides and amides, it was chosen as the solvent. The [n(NH)] bands of these compounds in CH 2 Cl 2 are shifted to lower wavenumbers of 10-20 cm À1 than those in CCl 4 [7,10]. The FTIR spectra of I-III, tripeptides IV-VIII and KNI-272, and tetrapeptides IX-XIV were measured in CH 2 Cl 2 at a concentration that prevented selfassociation of the hydroxy and amido groups.…”

Section: Ftir Spectroscopymentioning

confidence: 99%

Intramolecular hydrogen bondings and conformations of peptidic HIV-1 protease inhibitors studied by FTIR and CD spectroscopies

Takasuka

Fujioka

Iwata

2005

Vibrational Spectroscopy

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Infrared Studies of the Association of Secondary Amides in Various Solvents

Cited by 76 publications

References 3 publications

Influences of monomer self‐association on the radical solution homopolymerization of N‐[3‐(dimethylamino)propyl](meth)acrylamide

Influences of monomer self‐association on the radical solution homopolymerization of N‐[3‐(dimethylamino)propyl](meth)acrylamide

Hydrogen bonding and chemical shift assignments in carbazole functionalized isocyanides from solid-state NMR and first-principles calculations

Intramolecular hydrogen bondings and conformations of peptidic HIV-1 protease inhibitors studied by FTIR and CD spectroscopies

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