Acid-induced conformational alteration of cis-preferential aromatic amides bearing N-methyl-N-(2-pyridyl) moiety

Okamoto, Iwao; Terashima, Masayuki; Masu, Hyuma; Nabeta, Mayumi; Ono, Kaori; Morita, Nobuyoshi; Katagiri, Kosuke; Azumaya, Isao; Tamura, Osamu

doi:10.1016/j.tet.2011.08.085

Cited by 35 publications

(30 citation statements)

References 39 publications

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“…The interconversion of conformers is difficult because of the partly double character of the C−N amidic bond. The geometry of amidic groups in pyridine‐related amides is a subject of interest due to their possible application as molecular devices ,,. Moreover, the amidic bond folding processes are of great importance due to their high impact on photophysical properties of the molecules ,.…”

Section: Resultsmentioning

confidence: 99%

Screening of the Structure of Americium Extractants Based on a 2,2’‐Bipyridyl Scaffold: a Simple Way to a N2,O2‐Tetradentate Ligands Library for Rational Design of An/Ln Extractants

et al. 2018

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A library of N-ethylanilides of 2,2'-bipyridine-6,6'-dicarboxylic acids were synthesized to evaluate the influence of the side chains on the extraction properties. The structure of the various diamides is studied in solid state by X-ray and in solution by 2D NMR. In the solid-state, the diamides featured flat Cs geometry irrespective of the nature and position of the substituents. Carboxylic groups in the crystals shifted from the residing planes of both pyridine and aromatic anilide rings indicating disruption of the conjugated system. The solution behaviour is substituent dependent. Only three types of relative orientations of amidic fragments and pyridine rings were found in solutions of diamides depending on the nature of the amidic side chain substituents. The conformations of the diamides mostly depended on the size of the substituent and less on their electronic properties. Solubility of the diamides and their metal extraction properties in relation to americium and europium ions were studied the diamides, bearing substituents in pyridine rings and in phenyl ring of diamide moiety (one or two alkyl-, alkoxy-, fluorine-, carboxylic-groups). The symmetrical substitution in the pyridine moiety critically diminished both solubility and metal extraction. Metal ions recovery strongly depended on the substitution in the anilidic moiety; distribution coefficients depended more on the spatial arrangement of the substituents and to a lesser extent on their electronic properties.[a] Dr.

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Section: Resultsmentioning

confidence: 99%

Screening of the Structure of Americium Extractants Based on a 2,2’‐Bipyridyl Scaffold: a Simple Way to a N2,O2‐Tetradentate Ligands Library for Rational Design of An/Ln Extractants

et al. 2018

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“…Aminopyridine rings are cis relative the oxygen atom of amidic group. The latter is fundamental difference of represented structure from N-alkylanilides of 2,2′-bipyridyl-6,6′-dicarboxylic acid [11,13] and N-alkylanilides of 2,6-pyridinedicarboxylic acid [16,17]. Contrary to the tertiary amides of 2,2′-bipyridyl-6,6′-dicarboxylic acid, the molecule of 2a is almost flat: the torsion angle N1-C6-C6′-N1′ is 180.0(1)°.…”

Section: Compound Number and Structurementioning

confidence: 99%

“…The angle between pyridine rings of bypyridyl moiety and aminopyridine groups is 23.19°. Torsion angle N1-C2-C1-N2 is 3.4(2)°, which evidenced the better conjugation between bipyridyl moiety and amidic group and aminopyridine aromatic ring when comparing with N-ethyl-derivatives [16,17]. The complexes with nitrates of lanthanum, samarium, europium, and dysprosium were synthesized by interaction of the ligands with nitrates of corresponding metals in acetonitrile (Scheme 4).…”

Section: Compound Number and Structurementioning

confidence: 99%

Effect of Heterocyclic Ring on LnIII Coordination, Luminescence and Extraction of Diamides of 2,2′-Bipyridyl-6,6′-Dicarboxylic Acid

et al. 2019

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We have synthesized and examined several complexes of lanthanides with diamides of 2,2′-bipyridyl-6,6′-dicarboxylic acid bearing various hetaryl-based side chains for the elucidation of the effect of the heterocycle on the structure and properties of the ligands. The multigram scale methods for the preparation of various N-alkyl-hetaryls and their diamides were developed. The solid state structure of 6-methyl-2-pyridylamide of 2,2′-bipyridyl-6,6′-dicarboxylic acid possesses a flat structure where the conformation is completely different from that previously observed for N-alkylated 2,2′-bipyridyl-6,6′-dicarboxamides and 2,6-pyridinedicarboxamides. The complexes of new ligands were synthesized and NMR and X-Ray studied their structure in solution and solid state. The results demonstrate that complexes possess the same structures both in solid state and in solution. Stability constants of the complexes were less when comparing with dimethyl-substituted diamides, but higher than for unsubstituted dianilide. Contrarily, the extraction ability of 2-pyridyl-diamide is significantly lower than for corresponding anilide. Specific interaction of extractant with solvent molecules, which is not available for electron-sink pyridine amides, can explain this. The luminescence of new Eu complexes was significantly higher than for all previously 2,2′-bipyridyl-6,6′-dicarboxamides and QY reaches 18%. Asymmetry ratios of Eu complexes were 25% higher when compared other complexes with 2,2′-bipyridyl-6,6′-dicarboxamides, which indicates large deviation from the inversion center.

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“…The fourth possible conformer (ZE) is the same as EZ, due to the C2 symmetry axis in the molecule (Figure 2), and all conformers are actually the racemic mixture of the RR and SS enantiomers, which cannot be discriminated by NMR. This analysis assumes free rotation around Ar-N bonds, as hindered rotation for these bonds is usually described only for 2substituted tertiary anilides [23][24][25]. Each formamide is denoted as E(E), Z(Z), E(Z) and Z(E) according to its own configuration and to the other one, specified between brackets.…”

Section: Conformational Analysis and Nmr Assignment In Chloroformmentioning

confidence: 99%

Long-range anisotropic effects in a V–shaped Tröger's base diformanilide: Conformational study by NMR assignment and DFT calculations

Trupp¹,

Laurella

Tettamanzi

et al. 2018

Journal of Molecular Structure

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Herein we describe the synthesis and conformational analysis of a Tröger's base diformanilide whose distinctive NMR spectra was fully assigned via DFT calculations. The complexity of the spectra originated by the presence of three conformers in equilibrium shows that the nuclei in each side of the molecule are sensitive to the configuration not only of the closest formamide moiety but also of the farthest one, due to long-range anisotropic effects. The temperature and the solvent polarity influence were analyzed to determine the different conformer populations and the corresponding rotational activation parameters.

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Acid-induced conformational alteration of cis-preferential aromatic amides bearing N-methyl-N-(2-pyridyl) moiety

Cited by 35 publications

References 39 publications

Screening of the Structure of Americium Extractants Based on a 2,2’‐Bipyridyl Scaffold: a Simple Way to a N2,O2‐Tetradentate Ligands Library for Rational Design of An/Ln Extractants

Screening of the Structure of Americium Extractants Based on a 2,2’‐Bipyridyl Scaffold: a Simple Way to a N2,O2‐Tetradentate Ligands Library for Rational Design of An/Ln Extractants

Effect of Heterocyclic Ring on LnIII Coordination, Luminescence and Extraction of Diamides of 2,2′-Bipyridyl-6,6′-Dicarboxylic Acid

Long-range anisotropic effects in a V–shaped Tröger's base diformanilide: Conformational study by NMR assignment and DFT calculations

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