Self-assembly into infinite tapes by 2,7-disubstituted-1,8-naphthyridines in the solid state

Bailey, Andrew J.; Grossel, Martin C.

doi:10.1039/c0ce00243g

Cited by 6 publications

(4 citation statements)

References 38 publications

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“…This shows that 2 in its dimeric form has a weak C–H···OC hydrogen bond that can solidify the conformational form (Figure ) and prevent it from rotating to create the forms with intramolecular N–H···N H-bonding. Although this effect is relatively weak, intermolecular or intramolecular H-bonding of C–H···N/O has been reported earlier. , The change in the chemical shift (8.19–6.83 ppm) of the aromatic proton in the proximity of OC (dark blue) is also induced due to an anisotropic deshielding cone of OC in full agreement with similar heterocyclic ureas. ,, This interaction is more probable in the case of the hydrogen-bonded dimer in which rotation is limited due to six hydrogen bonds with the other monomer. Therefore, when the intermolecular H-bonding is broken, the rotation occurs implying that in the monomeric form, keto tautomer is more stable, whereas the keto dimer is a stable conformation when the two stickers are in close proximity to each other, in nonpolar solvents or the melt state.…”

Section: Resultssupporting

confidence: 77%

“…Although this effect is relatively weak, intermolecular or intramolecular H-bonding of C–H···N/O has been reported earlier. 34,35 The change in the chemical shift (8.19–6.83 ppm) of the aromatic proton in the proximity of O=C (dark blue) is also induced due to an anisotropic deshielding cone of O=C in full agreement with similar heterocyclic ureas. 33,34,36 This interaction is more probable in the case of the hydrogen-bonded dimer in which rotation is limited due to six hydrogen bonds with the other monomer.…”

Section: Resultsmentioning

confidence: 83%

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Supramolecular Mimic for Bottlebrush Polymers in Bulk

Golkaram¹,

Boetje²,

Dong³

et al. 2019

ACS Omega

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A series of poly(tetrahydrofuran)s with molecular weights above entanglement molecular weight Me were synthesized, and one of their end-groups was functionalized with a supramolecular entity so that the corresponding polymers form a brushlike structure suitable for comparison with conventional irreversible bottlebrush polymers. To compare their relaxation mechanisms, linear rheology was employed and showed that a hierarchical relaxation, which is usually observed in bottlebrush polymers, occurs in these materials, too. The polymer chain segments close to the supramolecular backbone are highly immobilized due to strong association in the center of polymer brush and cannot relax via reptation mechanism, which is mainly responsible for linear entangled polymer relaxations. Therefore, disentanglement can take much longer through contour length fluctuations and arm retraction processes similar to covalent bottlebrush polymers and combs. The relaxed ends of polymers then act as solvent to let the remaining segments of the polymeric brush undergo Rouse-like motions (constraint release Rouse). At longer times, additional plateau appears, which can be attributed to the relaxation of the entire supramolecular bottlebrush polymer via hopping or reptative motions. With an increase of temperature, viscoelastic solid behavior turns into viscoelastic liquid due to reversible depolymerization of the supramolecular backbone of the bottlebrush polymer. The elastic modulus (G′ in the order of kPa) was much less than the values found for the entanglement plateau modulus of linear poly(tetrahydrofuran) (in order of MPa). This low modulus value, which exists up to very low frequencies (high temperatures), makes them a good candidate for supersoft elastomers.

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Section: Resultssupporting

confidence: 77%

Section: Resultsmentioning

confidence: 83%

Supramolecular Mimic for Bottlebrush Polymers in Bulk

Golkaram¹,

Boetje²,

Dong³

et al. 2019

ACS Omega

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“…Thus, taking into account SIs in the quadruple hydrogen bonded complexes, ADDA/DAAD-type complex is more stable than ADAD/ DADA-pair [19,22,42]. It is known that 2,7-disubstituted-1,8-naphthyridines form quadruple hydrogen bonded complexes [9,15,36,[43][44][45], which in the case of 7-acylamino-[1H]-2-oxo-1,8-naphthyridine are stabilized by an ADAD/DADA motif [19]. It is also worth to mention that even weak CHÁÁÁN/O hydrogen bonding contacts may stabilize the infinite tapes of 2,7-disubstituted-1,8-naphthyridines in crystal [45].…”

Section: Introductionmentioning

confidence: 96%

“…It is known that 2,7-disubstituted-1,8-naphthyridines form quadruple hydrogen bonded complexes [9,15,36,[43][44][45], which in the case of 7-acylamino-[1H]-2-oxo-1,8-naphthyridine are stabilized by an ADAD/DADA motif [19]. It is also worth to mention that even weak CHÁÁÁN/O hydrogen bonding contacts may stabilize the infinite tapes of 2,7-disubstituted-1,8-naphthyridines in crystal [45]. The aim of this work is to perform a systematic study on the steric and electronic effects affecting the intermolecular interactions in 7-acylamino-[1H]-2-oxo-1,8-naphthyridines (Scheme 1) because very scarce data on the topic has been published so far [19,39].…”

Section: Introductionmentioning

confidence: 99%

Intermolecular steric hindrance in 7-acylamino-[1H]-2-oxo-1,8-naphthyridines: NMR, ESI-MS, IR, and DFT calculation studies

et al. 2011

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Intermolecular interactions of 7-(RCONH)-[1H]-2-oxo-1,8-naphthyridines (R = Me, Et, i-Pr, t-Bu, 1-adamantyl (1-Ad), CF 3 , and C 2 F 5 ) containing ADAD quadruple hydrogen bonding motif were studied by liquid and solid state NMR, ESI-MS, IR, and DFT calculations. 1 H NMR was used to determine the dimerization constants of i-Pr and 1-Ad congeners in CDCl 3 . 13 C and 15 N crosspolarization (CP) magic angle spinning (MAS) NMR data suggest that compounds possess similar solid state structures. Further, mass spectral data reveal that in gas phase both Me and 1-Ad derivatives form also multimers due to lack of competitive solvent interactions. The structures of the gas phase multimers depend on the size of the alkyl group. These results are in agreement with quantum chemical calculations. Geometry optimization and 1 H NMR spectra show that in dimers that carry bulky alkyl groups (t-Bu and 1-Ad) certain hydrogen bonds are weaker than in Me, Et, and i-Pr derivatives while strong electron acceptors, CF 3 and C 2 F 5 , deshields hydrogen bonded protons but creates significant electronic F/O repulsion yielding lowering of the energy of interaction. The influence of steric effect on dimerization of quadruply hydrogen bonded dimers was correlated with the Taft E s values.

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1,8‐Naphthyridinecarbaldehydes and Their Methyl‐Substituted Precursors: Synthesis, Molecular Structures, Supramolecular Motifs and Trapped Water Clusters

et al. 2017

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1,8‐Naphthyridinecarbaldehydes bearing chlorine, pyrrolidinyl, piperidinyl or morpholinyl groups, were synthesised by oxidation of their methyl‐substituted precursors. The prepared carbaldehydes represent valuable starting materials for the construction of systems that are useful for supramolecular and medicinal chemistry. Single‐crystal X‐ray diffraction studies of four carbaldehydes and six methyl derivatives provided interesting information about the supramolecular motifs in the crystal structures of solvent‐free and solvated naphthyridines. The formation of interesting water clusters, for example, T4(2) water tape, was observed in the case of 7‐methyl‐2‐(piperidin‐1‐yl)‐1,8‐naphthyridine as well as in the crystal structure of a by‐product 7‐(morpholin‐1‐yl)‐1,8‐naphthyridine‐2‐carboxylic acid. Knowledge of the detailed structural properties of water clusters is of great research interest to a broad range of scientific disciplines.

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Self-assembly into infinite tapes by 2,7-disubstituted-1,8-naphthyridines in the solid state

Cited by 6 publications

References 38 publications

Supramolecular Mimic for Bottlebrush Polymers in Bulk

Supramolecular Mimic for Bottlebrush Polymers in Bulk

Intermolecular steric hindrance in 7-acylamino-[1H]-2-oxo-1,8-naphthyridines: NMR, ESI-MS, IR, and DFT calculation studies

1,8‐Naphthyridinecarbaldehydes and Their Methyl‐Substituted Precursors: Synthesis, Molecular Structures, Supramolecular Motifs and Trapped Water Clusters

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