How the π Conjugation Length Affects the Fluorescence Emission Efficiency

Yamaguchi, Yoshihiro; Matsubara, Yoichi; Ochi, Takanori; Wakamiya, Tateaki; Yoshida, Zen‐ichi

doi:10.1021/ja8040493

Cited by 205 publications

(198 citation statements)

References 19 publications

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“…[30] Recently, a rudimentary definition of the effective conjugation length (A p ) made use of Equation (1), in which b is an unspecified constant taken to equal unity. [31] Although there is a smooth evolution of F F with the A p value computed from Equation (1), this is not a useful definition of the effective conjugation length for molecular systems. Indeed, there is no global correlation between A p and, for example, the emission maximum, although the data derived for the B series do show a smooth evolution.…”

Section: Resultsmentioning

confidence: 99%

Quasi‐One‐Dimensional Electronic Systems Formed from Boron Dipyrromethene (BODIPY) Dyes

Ziessel

Rihn

Harriman

2010

Chemistry A European J

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Synthetic strategies have been devised that allow the rational design and isolation of highly coloured boron dipyrromethene (BODIPY) dyes that absorb across much of the visible region. Each dye has an aryl polycycle (usually pyrene or perylene) connected to the central BODIPY core through a conjugated tether at the 3,5-positions. Both mono- and difunctionalised derivatives are accessible, in certain cases containing both pyrene and perylene residues. For all new compounds, the photophysical properties have been recorded in solution at ambient temperature and in a glassy matrix at 77 K. The presence of the aryl polycycle(s) affects the absorption and emission maxima of the BODIPY nucleus, thereby confirming that these units are coupled electronically. Indeed, the band maxima and oscillator strengths depend on the conjugation length of the entire molecule, whereas there is no sign of fluorescence from the polycycle. As a consequence, the radiative rate constant tends to increase with each added appendage. The nature of the linkage (styryl, ethenyl, or ethynyl) also exerts an effect on the photophysical properties and, in particular, the absorption spectrum is perturbed in the region of the aryl polycycle. The perylene-containing BODIPY derivatives absorb over a wide spectral range and emit in the far-red region in almost quantitative yield. A notable exception to this generic behaviour is provided by the anthracenyl derivative, which exhibits charge-transfer absorption and emission spectra in weakly polar media at ambient temperature. Regular BODIPY-like behaviour is restored in a glassy matrix at 77 K. Overall, these new dyes represent an important addition to the range of strongly absorbing and emitting reagents that could be used as solar concentrators.

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Section: Resultsmentioning

confidence: 99%

Quasi‐One‐Dimensional Electronic Systems Formed from Boron Dipyrromethene (BODIPY) Dyes

Ziessel

Rihn

Harriman

2010

Chemistry A European J

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“…We have also used extended conjugated active methylene but we got the rearranged product. All the final products were carefully purified and fully characterized by 1 H NMR, 13 C NMR and HRMS, which confirmed the expected molecular structures. The 1 H NMR spectra of the dye COS4 showed doublet peaks at 7.90 ppm and at 6.91 ppm having trans vicinal coupling constant (J = 15.5 Hz) which indicates that the olifinic protons at π-bridge are in trans form.…”

Section: Chemistrymentioning

confidence: 62%

“…Due to this limitation there is need to develop luminescent molecules with strong solid state and aggregate state emission properties. In the last decades, AIE molecules involving intramolecular restriction [11,12], planarity and rotation ability [13], twisted intramolecular charge transfer (TICT) [14][15][16] have been reported, since the first report of AIE material by Tang and co-workers in 2001 [17]. In recent years, variety of fluorophores have been designed and synthesized with conjugated [18] and twisted skeleton to exhibit AIE [12,19].…”

Section: Introductionmentioning

confidence: 99%

AIE Based Coumarin Chromophore - Evaluation and Correlation Between Solvatochromism and Solvent Polarity Parameters

Lanke

Sekar

2015

J Fluoresc

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A new class of red emitting extensively conjugated donor-π-acceptor type dyes bearing coumarin units have been synthesized by condensation of 7-(diethylamino)-2-oxo-2 H-chromene-3-carbaldehyde with different active methylenes. All the dyes are characterized by (1)H NMR, (13)C NMR and HRMS spectroscopy. The photophysical behaviour and the relation between structure and properties of the coumarin "push-pull" derivatives were investigated experimentally. The dyes exhibited positive solvatochromism and solvatofluorism in solution of varying polarity. These coumarin dyes show aggregation induced emission properties with red emitting fluorescence. They show absorption in the range of 501-528 and emission in the range of 547-630 nm. We evaluated photophysical properties of coumarin dyes using solvotochromism and solvent dependent shift in the emission wavelength. All the synthesized coumarin dyes COS1-COS4 are showing very good solvatochromic properties.

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“…[21][22][23][24][25][26][27] It has been reported that the uores-cence emission efficiency is affected by the p-conjugation length of compounds. 28 In the cases of TPE derivatives, the introduction of PAHs can extend the p-conjugation of compounds and their good performance in emission suggests that enlarging the pconjugation degree of AIE compounds is an effective strategy to obtain solid-state dyes. Based on this fact, we speculate that in solid state, intramolecular rotation of AIE compounds can be effectively restricted and p-p interactions are completely absent, whether the emission efficiency would increase with the increasing p-conjugation?…”

mentioning

confidence: 99%

A series of 4,5,9,10-tetrahydropyrene-based tetraarylethenes: synthesis, structures and solid-state emission behavior

et al. 2018

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By controlling the number of 4,5,9,10-tetrahydropyrene segments around the tetraarylethene core, a series of 4,5,9,10-tetrahydropyrene-based tetraarylethenes were synthesized and structurally characterized. An aggregation-induced emission (AIE) study indicated that all the compounds are AIE active: they are weak emitters in good solvents but highly emissive in the condensed phase, and hence are potential solidstate emitters. Their optical properties, electrochemical properties and theoretical calculations were investigated, and the results prove that the p-conjugation degree of these compounds increases with the increasing number of 4,5,9,10-tetrahydropyrene units. However, the fluorescence quantum yield in the solid state doesn't increase with increasing p-conjugation. We studied the reason for this by analyzing the crystal structures of some compounds, and proposed that the close degree of molecular packing in the solid state may be responsible for it. Loose packing of tetraarylethenes in the solid state can restrict the rotation of the aromatic rings but cannot constrain other non-radiative pathways efficiently, such as vibration, which leads to the unpredictable emission of the compounds. IntroductionThe design and synthesis of organic materials with efficient solid-state uorescence has attracted extensive attention because the performance of organic photoelectric devices is usually dependent on the solid-state properties of materials. 1-4And most luminogenic molecules, especially those with disclike shapes, normally exhibit quenched emission in the condensed state due to the formation of intermolecular pstacking interactions.5-7 Several strategies have been developed to solve this problem such as designing polymers with dendritic structures and using antiaggregation reagents to modulate aggregation. [8][9][10] In these methods, the design ideas are obstructing the formation of luminophoric aggregates. Recently, it has been proved that the construction of organic compounds with aggregation-induced emission property is a convenient but effective way to obtain outstanding luminogens.11-16 Different from the ordinary organic compounds usually with excellent single-molecule emission in solvents, AIE compounds are weakly emissive in good solvent but they become strong emitters when the condensed phase are formed. 17In aggregates, intramolecular rotation which acts as a nonradiative pathway can be restricted effectively, meanwhile the twisted structure of these compounds can avoid the formation of p-stacking to a certain extent, thus achieving high solid-state emission efficiency. As a representative member of AIE dyes, tetraphenylethene (TPE) has attracted much research attention because it enjoys the advantages such as efficient solid-state emission, facile synthesis and easy functionalization.18-20 In addition, by combing TPE and many kinds of polycyclic aromatic hydrocarbons (PAHs), a large number of novel TPE derivatives have been developed. [21][22][23][24][25][26][27] It has been reported that the uores-c...

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How the π Conjugation Length Affects the Fluorescence Emission Efficiency

Cited by 205 publications

References 19 publications

Quasi‐One‐Dimensional Electronic Systems Formed from Boron Dipyrromethene (BODIPY) Dyes

Quasi‐One‐Dimensional Electronic Systems Formed from Boron Dipyrromethene (BODIPY) Dyes

AIE Based Coumarin Chromophore - Evaluation and Correlation Between Solvatochromism and Solvent Polarity Parameters

A series of 4,5,9,10-tetrahydropyrene-based tetraarylethenes: synthesis, structures and solid-state emission behavior

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