Synthesis, crystal structure and dynamic behavior of naphthalene-based calix[3]amide: Cyclic trimers of 2-alkylamino-6-naphthoic acid

Katagiri, Kosuke; Sawano, Kanako; Okada, Miho; Yoshiyasu, Shiho; Shiroyama, Reiko; Ikejima, Norio; Masu, Hyuma; Katō, Takako; Tominaga, Masahide; Azumaya, Isao

doi:10.1016/j.molstruc.2008.04.020

Cited by 7 publications

(7 citation statements)

References 18 publications

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“…It turned out to be a cyclic trimer of 1b , which had been synthesized in a different manner by Azumaya and coworkers. 15 This cyclic trimer, the amount of which did not increase with the progress of polymerization, was probably formed by self‐condensation of 1b in the early stage of polymerization, where deprotonated 1b could react with 1b untreated with base. As the polymerization of the corresponding p ‐substituted benzene monomer did not afford cyclic oligomers as byproducts under the same conditions, 14 the proton abstraction by the base from the amino group of 1b might be slower than that in the benzene monomer, resulting in the occurrence of the reaction of deprotonated 1b with nondeprotonated 1b .…”

Section: Resultsmentioning

confidence: 97%

Synthesis of poly(naphthalenecarboxamide)s with low polydispersity by chain‐growth condensation polymerization

Mikami

Daikuhara

Kasama

et al. 2011

J. Polym. Sci. A Polym. Chem.

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Condensation polymerization of 6‐(N‐substituted‐amino)‐2‐naphthoic acid esters (1) was investigated as an extension of chain‐growth condensation polymerization (CGCP). Methyl 6‐(3,7‐dimethyloctylamino)‐2‐naphthoate (1b) was polymerized at −10 °C in the presence of phenyl 4‐methylbenzoate (2) as an initiator and lithium 1,1,1,3,3,3‐hexamethyldisilazide (LiHMDS) as a base. When the feed ratio [1a]0/[2]0 was 10 or 20, poly(naphthalenecarboxamide) with defined molecular weight and low polydispersity was obtained, together with a small amount of cyclic trimer. However, polymer was precipitated during polymerization under similar conditions in [1a]0/[2]0 = 34. To increase the solubility of the polymer, monomers 1c and 1d with a tri(ethylene glycol) (TEG) monomethyl ether side chain instead of the 3,7‐dimethyloctyl side chain were synthesized. Polymerization of the methyl ester monomer 1c did not proceed well, affording only oligomer and unreacted 1c, whereas polymerization of the phenyl ester monomer 1d afforded well‐defined poly(naphthalenecarboxamide) together with small amounts of cyclic oligomers in [1d]0/[2]0 = 10 and 29. The polymerization at high feed ratio ([1d]0/[2]0 = 32.6) was accompanied with self‐condensation to give polyamide with a lower molecular weight than the calculated value. Such undesirable self‐condensation would result from insufficient deactivation of the electrophilic ester moiety by the electron‐donating resonance effect of the amide anion. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

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Section: Resultsmentioning

confidence: 97%

Synthesis of poly(naphthalenecarboxamide)s with low polydispersity by chain‐growth condensation polymerization

Mikami

Daikuhara

Kasama

et al. 2011

J. Polym. Sci. A Polym. Chem.

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“…The disordered moieties have two carbon atoms in common (C14/C14B) and (C2/C2B). It is worth noting that the crystal structure of CoumDimer shows almost the same dihedral angle as the cyclic trimer comprised of three units of 2‐amino‐6‐naphthoic acid …”

Section: Resultsmentioning

confidence: 99%

The Coumarin‐Dimer Spring—The Struggle between Charge Transfer and Steric Interactions

Kielesiński

Morawski

Sobolewski

et al. 2017

Chemistry A European J

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The synthesis of a weakly coupled, strongly polarized coumarin dimer has been achieved for the first time. The three-step strategy comprises the Skattebøl formylation followed by the Knoevenagel reaction and the formation of a tertiary amide by using a peptide-type procedure. The molecule consists of two different coumarin moieties: One is a classical donor-acceptor system and the second one possesses a weaker amide donor at the 7-position. The polarized coumarin dimer can form an electronically conjugated structure possessing an electric dipole larger than that of 7-(dimethylamino)coumarin-3-carboxylic acid. The limited flexibility of the inter-coumarin connection results in stable conformers of different electric dipole moments and complex photophysics. In the solid state, this compound has a strongly bent conformation with the two coumarin units forming an angle of around 74°. In solution, two conformers are in equilibrium. The existence of the molecule as two conformers in the ground state has been confirmed by optical studies, and further corroborated by molecular calculations. The fluorescence spectra possess a unique feature: A charge-transfer band (ca. 550 nm) is visible only in nonpolar or weakly polar solvents. Optical spectroscopy studies coupled with molecular calculations allowed us to rationalize this phenomenon: The large amplitude of intramolecular motions is responsible for the conformational isomerization as well as producing a conical intersection between the potential energy surfaces of the excited singlet state and the ground state, which opens an internal conversion channel that effectively competes with the fluorescence of the conformers.

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“…Azumaya and co-workers reported that the self-condensation reaction of 6-allylamino-2-naphthoic acid readily afforded a cyclic trimer . Inspired by this work, we anticipated that N-substituted poly(2,6-naphthalenecarboxamide)s would adopt a helical conformation .…”

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confidence: 88%

“…along the short axis of the naphthalene ring, 12 this CD behavior can be attributed to solvent-dependent change of the syn-anti ratio of two successive naphthalene rings in poly1 h . 8 The polyamide with lower molecular weight, poly1 l , exhibited similarly shaped CD spectra, but the intensity was lower compared to that of poly1 h ( Figure S3). Molecular-weight-dependent CD intensity is often observed in helical polymers.…”

mentioning

confidence: 96%

“…Azumaya and co-workers reported that the self-condensation reaction of 6-allylamino-2-naphthoic acid readily afforded a cyclic trimer. 8 Inspired by this work, we anticipated that N-substituted poly(2,6-naphthalenecarboxamide)s would adopt a helical conformation. 9 Since the naphthalene ring is more hydrophobic than the benzene ring, the helical folding of the naphthalene polyamide is expected to be prompted by the solvophobic effect more efficiently than in the case of N-substituted poly( p-benzamide)s. Furthermore, we expected that it would be easy to identify the helical structure by measuring CD spectra because the direction of the electric transition dipole moments of 6-acylamino-2-naphthalenecarboxamide derivatives is thought to be similar to that of 6-methoxy-2-naphthoic acid esters, which have used as CD chromophores for the exciton chirality method.…”

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confidence: 97%

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Helical Folding of Poly(naphthalenecarboxamide) Prompted by Solvophobic Effect

et al. 2009

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Much attention has been paid to controlling the helical structure of polymers, oligomers, and supramolecules by utilizing solvophobic effect, hydrogen bonding, and other noncovalent interactions 1 because the one-handed helical conformations of biological macromolecules, such as DNA and proteins, which are stabilized by these interactions, are crucial for molecular recognition and information storage. 2 For instance, oligo(m-phenylene ethynylene)s with oligo(ethylene glycol) side chains recognize chiral small molecules on the basis of a folded helical structure induced by a solvophobic effect; in polar solvents, the polar side chain of the oligomers is solvated, but the hydrophobic main chain is intramolecularly self-associated. 3 This amphiphilic type of heterogeneity is crucial for induction of helical folded structure. On the other hand, helical poly(phenylacetylene) bearing an alanine residue with a long alkyl chain adopts a helical structure stabilized by hydrogen bonding. 4 Furthermore, hydrogen-bondassisted helical folded structures of aromatic oligoamides have been reported. 5 However, solvophobic effect-induced helical folding of aromatic oligoamide and polyamide has not been reported yet.We have demonstrated that poly( p-benzamide)s with a chiral tri(ethylene glycol) side chain adopt a thermodynamically controlled one-handed helical conformation in solution. 6 The helical structure was confirmed by X-ray crystallographic analysis of oligo(N-methyl-p-benzamide)s, which adopt a helical conformation with three monomer units per turn in the crystal, and by exciton model analysis of the CD spectra induced by the secondary structure of the polyamide. As for the effect of solvents, we have shown that the polyamide adopts the helical conformation in common organic solvents, such as chloroform, acetonitrile, and methanol, and clear solvent dependency has not been observed. However, the effects of more polar solvents, such as mixtures of water and methanol, have not been clarified. On the other hand, the CD spectra of poly(m-benzamide)s having chiral side chains suggest that these meta-type polyamides adopt different conformations in water from those in organic solvents, 7 but unambiguous evidence for the helical structure of the polyamides has not been obtained due to the difficulties of exciton model analysis of the CD spectra.Azumaya and co-workers reported that the self-condensation reaction of 6-allylamino-2-naphthoic acid readily afforded a cyclic trimer. 8 Inspired by this work, we anticipated that N-substituted poly(2,6-naphthalenecarboxamide)s would adopt a helical conformation. 9 Since the naphthalene ring is more hydrophobic than the benzene ring, the helical folding of the naphthalene polyamide is expected to be prompted by the solvophobic effect more efficiently than in the case of N-substituted poly( p-benzamide)s. Furthermore, we expected that it would be easy to identify the helical structure by measuring CD spectra because the direction of the electric transition dipole moments of 6-acylamino-2-n...

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Synthesis, crystal structure and dynamic behavior of naphthalene-based calix[3]amide: Cyclic trimers of 2-alkylamino-6-naphthoic acid

Cited by 7 publications

References 18 publications

Synthesis of poly(naphthalenecarboxamide)s with low polydispersity by chain‐growth condensation polymerization

Synthesis of poly(naphthalenecarboxamide)s with low polydispersity by chain‐growth condensation polymerization

The Coumarin‐Dimer Spring—The Struggle between Charge Transfer and Steric Interactions

Helical Folding of Poly(naphthalenecarboxamide) Prompted by Solvophobic Effect

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