Molecular Design of Highly Fluorescent Dyes

Niko, Yosuke; Konishi, Gen‐ichi

doi:10.5059/yukigoseikyokaishi.70.918

Cited by 18 publications

(8 citation statements)

References 81 publications

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“…Next, we were attentive to find out the difference in the dipole moment between excited and ground state, being an important parameter to decipher the solvatochromism. On the basis of the reported weak donor- and strong acceptor-linked fluorophore, 8,9 we expected a larger dipole moment for the excited state in comparison to the ground state for these molecules. In fact, significant increments of Stokes shift by changing apolar to polar medium also indicate that the emitting state’s dipole moment (μ) is more than the ground state.…”

Section: Resultsmentioning

confidence: 94%

“…8 The nitroaromatics A and B were reported to be strong fluorescent compounds where B , in particular, displayed dual Fl. 9 Further, a comparative study on the impact between cyano and nitro functionality toward solvatochromism for a biphenyl system with a strong (amine) donor was known in the literature studies 4a,1b where the cyano group offered strong emission and solvent-dependence in comparison to nitro. 1b…”

Section: Introductionmentioning

confidence: 99%

“…Despite these common tendencies of nitroaromatics, many fluorophores were identified to exhibit excellent quantum yield in aprotic medium. , With an aim of finding unusual photophysical behavior, Konishi explored the solvatochromic fluorophores A–C (Figure ), attached with a relatively weak donor and strong acceptor . The nitroaromatics A and B were reported to be strong fluorescent compounds where B , in particular, displayed dual Fl . Further, a comparative study on the impact between cyano and nitro functionality toward solvatochromism for a biphenyl system with a strong (amine) donor was known in the literature studies , where the cyano group offered strong emission and solvent-dependence in comparison to nitro…”

Section: Introductionmentioning

confidence: 99%

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Weak Donor-/Strong Acceptor-Linked Anthracenyl π-Conjugates as Solvato(fluoro)chromophore and AEEgens: Contrast between Nitro and Cyano Functionality

et al. 2018

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Steady development on photophysical behaviors for a variety of organic fluorophores inspired us to generate anthracene-based fluorescent molecules with a strong acceptor and a significantly weak donor through a π-spacer. Such molecules are found to have substantial twisted conformational orientations in the solid state and enhanced apolar character because of the attachment of tolyl or mesityl group with an anthracenyl core. Upon exposure to a variety of solvents, strong solvatochromism was noticed for 4-nitro compound (84 nm red shift) in contrast to the cyano analogue (18 nm red shift). Both these probes were highly emissive in apolar solvents while nitro-analogue, in particular, could discriminate the solvents of E T (30) (a measure of microscopic solvent polarity) ranging from 31 to 37. Thus, 4-nitro compounds can be successfully employed to detect and differentiate the apolar solvents. On the contrary, the 2-nitro analogue is almost nonemissive for the same range of solvents perhaps because of favorable excited-state intramolecular proton-transfer process. The fundamental understanding of solvatochromic properties through the formation of twisted intramolecular charge-transfer (TICT) state is experimentally analyzed by synthesizing and studying the π-conjugates linked to only benzene in place of nitro or cyanobenzene, which exhibits no solvatochromism and that helped finding the possible emission, originated from the locally excited state. Moreover, the molecular structures for these compounds are determined by the single-crystal X-ray diffraction studies to examine the change in emission properties with molecular packing and alignment in the aggregated state. The measurement of dihedral angles between the substituents and anthracenyl core was helpful in finding the possible extent of electronic conjugations within the system to decipher both solvatochromism and aggregation enhanced emission (AEE)-behavior. The cyano analogue exhibited prominent AEE-behavior, whereas nitro analogues showed the aggregation-caused quenching effect. The reason behind such dissimilarity in solvatochromism and AEE-behavior between cyano- and nitro-linked anthracenyl π-conjugates are also addressed through experimental outcomes.

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Section: Resultsmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Weak Donor-/Strong Acceptor-Linked Anthracenyl π-Conjugates as Solvato(fluoro)chromophore and AEEgens: Contrast between Nitro and Cyano Functionality

et al. 2018

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“…13,14 Special attention has been paid to 1pyrenyl carbonyl compounds such as aldehyde, ketones, acids, esters, amides, etc., exhibiting strongly environment-sensitive uorescence and used as molecular probes. [15][16][17][18][19][20][21] Recent works by the Konishi group have provided a basis for understanding the photophysical properties of this class of uorophores. [15][16][17]21 As far as pyrenyl ketones are concerned, research reports have mainly concentrated on pyrenyl alkyl ketones.…”

Section: Introductionmentioning

confidence: 99%

“…[15][16][17][18][19][20][21] Recent works by the Konishi group have provided a basis for understanding the photophysical properties of this class of uorophores. [15][16][17]21 As far as pyrenyl ketones are concerned, research reports have mainly concentrated on pyrenyl alkyl ketones. This class of perylenyl uorophores shows short uorescence lifetimes (10 À9 -10 À8 s, compared with >10 À7 s for pyrene) and low quantum yields due to efficient intersystem crossing.…”

Section: Introductionmentioning

confidence: 99%