Polymorphic Equilibrium Responsive Thermal and Mechanical Stimuli in Light-emitting Crystals of <i>N</i>-Methylaminonaphthyridine

Harada, Naomi; Abe, Yukitaka; Karasawa, Satoru; Koga, Noboru

doi:10.1021/ol302963e

Cited by 55 publications

(66 citation statements)

References 18 publications

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“…10 N,N-BisĲ5,7-ditrifluoromethyl-1,8-naphthyridin-2-yl)amine (1). 1,8-Naphthyridine derivatives, 1,8Nap-NH 2 , 1,8Nap-Cl and 1,8Nap-NHMe, were prepared by using the procedure reported previously.…”

Section: Methodsmentioning

confidence: 99%

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Crystalline transformations of dinaphthyridinylamine derivatives with alteration of solid-state emission in response to external stimuli

et al. 2015

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Dinaphthyridinylamine derivatives, Ĳ1,8Nap) 2 NR (R = H (1), Me (2) and Ph (3)), were prepared as fluorophores in response to external stimuli. From crystallization, single crystals (1) containing water molecules as crystal solvents and crystal polymorphs (3-α and 3-β) containing MeOH molecules were obtained. In the crystal packing of 1, a γ-herringbone (γ-HB) fashion with π-π interaction was observed. In contrast, the packing of 3-α was in a HB fashion with intermolecular CH-N interaction, while the packing of 3-β was in a slipped columnar fashion with π-π interaction between the naphthyridine planes. The observed difference of crystal packings influenced the solid-state emission spectra. Crystals 1, 2 and 3 showed piezochromic behaviors, in which by thoroughly grinding the crystals, the solid-state emission blue color (λ f max = ca. 450 nm) turned into yellowish green (λ f max = ca. 510 nm) for the amorphous solid. In addition, crystals 3-α and 3-β showed various phase transitions including single-crystal-to-single-crystal (SCto-SC) transformation in response to external stimuli. Crystal 3-β desorbed the MeOH molecules under ambient atmosphere to provide crystal 3-β′ (λ f max = 449 nm), while the resulting crystal 3-β′ returned to crystal 3-β upon exposure to MeOH vapor, indicating vapochromic behavior. Furthermore, crystal 3-β′ was heated at ca. 160°C to afford crystal 3-α (SC-to-SC transformation). The gummy oil in the resulting supercooled liquid (SCL) state after melting the crystals was scratched by using a fine wire at and above 80°C (>T g , glass temperature) to form crystal 3-α with blue emission (SCL-to-SC transformation). CrystEngCommThis journal is

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Section: Methodsmentioning

confidence: 99%

“…3 They are known to show various crystal transformations between polymorphs. 10 This time, N,N-bisĲ5,7-ditrifluoromethylnaphthyrid-2-yl)amine derivatives ĲĲ1,8Nap) 2 NR; R = H (1), Me (2) and Ph (3) were prepared as new fluorophores. Many molecules exhibiting such polymorphism-dependent emission have been reported.…”

Section: Introductionmentioning

confidence: 99%

Crystalline transformations of dinaphthyridinylamine derivatives with alteration of solid-state emission in response to external stimuli

et al. 2015

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“…Reduction of 2 with tin afforded 2‐chloro‐3,5‐diaminopyridine ( 3 ) as a white solid. Finally, by Combes synthesis in the presence of hexafluoroacetylacetone and montmorillonite K10 as catalyst, 15Nap‐Cl was obtained as a yellowish solid.…”

Section: Resultsmentioning

confidence: 99%

“…Interestingly, the fluorescence quantum yields Φ fl are independent of the polarity of the solvents, and a relatively high Φ fl of 33 % was observed in water. As the polarity of the solvent increased, Φ fl increased, which is the opposite behavior to that of the typical push–pull‐type fluorophores such as TFMAQ and 18Nap derivatives . Compounds 15Nap‐EA , and 15Nap‐DEA have similar absorption spectra and similar

λ_{\max}^{ab}

values.…”

Section: Resultsmentioning

confidence: 99%

Fluorescence Properties and Exciplex Formation of Emissive Naphthyridine Derivatives: Application as Sensors for Amines

Hirota

Usui

Fuchi

et al. 2019

Chemistry A European J

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Water‐soluble donor–acceptor‐type fluorophore 15Nap‐Cl having two trifluoromethyl groups and a Cl group on a 1,5‐aminonaphthyridine framework was prepared. Fluorophore 15Nap‐Cl showed strong solvatochromic fluorescence, and, as the solvent polarity increased, a bathochromic shift was observed accompanied by an increase in the fluorescence quantum yield. In addition, in the presence of amines such as ethylamine, diethylamine, and aniline, further considerable bathochromic shifts in the fluorescence were observed. Density functional calculations identified the source of the fluorescence behavior as exciplex formation between 15‐Nap‐Cl and the corresponding amine. The fluorescence behavior was exploited to fabricate a sensor that can identify various primary, secondary, and tertiary amines.

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“…This is accompanied by a lower critical solution temperature (LCST) behavior, resulting in a turbid solution. In addition, UBD have been used in our laboratory for the development of functional materials; namely, radical nanoparticles have been employed for metal-free magnetic resonance imaging contrast agents [13], and push-pull-type, aminoquinoline-based fluorescent probes have been constructed for bioimaging applications [14][15][16][17][18]. Among the latter, we have successfully developed a tumor-imaging probe activated by heat treatment [19].…”

Section: Introductionmentioning

confidence: 99%

Effect of Hydrophobicity on the Self-Assembly Behavior of Urea Benzene Derivatives in Aqueous Solution

et al. 2018

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Urea benzene derivatives (UBD) with amphiphilic side chains showed self-assembly behavior in aqueous solution to form nanoparticles~100 nm in size. Subsequent thermal treatment led to additional self-assembly of the nanoparticles due to dehydration of the amphiphilic side chains, producing microparticles. This self-assembly process was accompanied by a lower critical solution temperature (LCST) behavior, as revealed by the abrupt decrease in solution transmittance. In this study, three UBD (UBD-1-3) with different lengths of the alkyl segment in the amphiphilic side chain (namely, hexyl, heptyl, and octyl, respectively) were prepared to investigate the self-assembly behavior in aqueous solution. UBD-1-3 formed identical nanoparticles, with sizes in the 10~80 nm range but with different LCST values in the order 3 < 2 < 1. These results suggest a relationship between the hydrophobicity and the self-assembly behavior of UBD.

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Polymorphic Equilibrium Responsive Thermal and Mechanical Stimuli in Light-emitting Crystals of N-Methylaminonaphthyridine

Cited by 55 publications

References 18 publications

Crystalline transformations of dinaphthyridinylamine derivatives with alteration of solid-state emission in response to external stimuli

Crystalline transformations of dinaphthyridinylamine derivatives with alteration of solid-state emission in response to external stimuli

Fluorescence Properties and Exciplex Formation of Emissive Naphthyridine Derivatives: Application as Sensors for Amines

Effect of Hydrophobicity on the Self-Assembly Behavior of Urea Benzene Derivatives in Aqueous Solution

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