Solution and solid-state Excited-State Intramolecular Proton Transfer (ESIPT) emitters incorporating Bis-triethyl-or triphenylsilylethynyl units

Massue, Julien; Felouat, Abdellah; Curtil, Mathieu; Vérité, Pauline M.; Jacquemin, Denis; Ulrich, Gilles

doi:10.1016/j.dyepig.2018.09.014

Cited by 37 publications

(32 citation statements)

References 46 publications

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“…Combining with the enlarged bond angle δ(O1 H2ÁÁÁN3) from 147.65 to 147.98 , we have the reasons to deem that the intramolecular hydrogen bond O1 H2ÁÁÁN3 of HNIBT-enol should be strengthened in S 1 state. [12,[53][54][55][56][57][58][59][60][61] In a similar manner, it can be found O1 H2 distance of HNIBT-MeOH-enol complex is increased in S 1 , whereas H2ÁÁÁN3 length of HNIBT-MeOH-enol complex is shortened with the enlarged bond angle δ(O1 H2ÁÁÁN3). Therefore, we can say the intramolecular hydrogen bond O1 H2ÁÁÁN3 of the HNIBT-MeOH-enol complex is also enhanced.…”

Section: Geometrical Structuressupporting

confidence: 65%

Revelation of ESIPT mechanism for the novel fluorescent system HNIBT in toluene and methanol solvents: A TDDFT study

Feng

et al. 2020

J Chinese Chemical Soc

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In this work, we devote to explore excited‐state intramolecular proton transfer (ESIPT) behavior for a novel fluorescent molecule naphthalimide‐based 2‐(2‐hydroxyphenyl)‐benzothiazole (HNIBT) [New J. Chem. 2019, 43, 9152.] in toluene and methanol (MeOH) solvents. Exploring weak interactions, stable HNIBT‐enol, and HNIBT‐MeOH‐enol complex can be found in S0 state via TDDFT/B3LYP/6‐311+G(d,p) level. Given photoexcitation, intramolecular hydrogen bond O1H2···N3 of HNIBT‐enol and HNIBT‐MeOH‐enol is dramatically enhanced, which offers impetus for facilitates ESIPT reaction. After repeated comparisons, we verify the unavailability of intermolecular hydrogen bonding effects between HNIBT‐enol and MeOH molecules. In view of excitation, HOMO (π) → LUMO (π*) transition and the changes of electronical densities indeed impulse ESIPT tendency. Via constructing potential energy curves (PECs), for both HNIBT‐enol and HNIBT‐MeOH‐enol complex, the ESIPT could only occur along with intramolecular hydrogen bond O1H2···N3. Through comparison, the potential barrier falls from 4.124 kcal/mol (HNIBT‐enol) to 2.132 kcal/mol (HNIBT‐MeOH‐enol). Therefore, we confirm that the ESIPT of the HNIBT system happens more easily in the MeOH solvent compared with the toluene solvent.

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Section: Geometrical Structuressupporting

confidence: 65%

Revelation of ESIPT mechanism for the novel fluorescent system HNIBT in toluene and methanol solvents: A TDDFT study

Feng

et al. 2020

J Chinese Chemical Soc

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“…HBO dyes 3 and 4 were synthesized according to reported procedures [24,41]. Generally speaking, HBO dyes 1 – 5 were prepared using a straightforward two-step procedure starting from commercially available mono-or bis-halogenated salicylaldehyde and 2-aminophenol.…”

Section: Methodsmentioning

confidence: 99%

“…In the solid-state, however, these detrimental motions are usually restricted or hindered and an enhancement of the fluorescence intensity is generally observed. Recently, several groups have successfully developed ESIPT emitters displaying good photoluminescent quantum yield in solution and in the solid-state, enlarging the potential fields of applications for these innovative dyes [22,23,24]. Nevertheless, providing additional examples of ESIPT dyes displaying strong fluorescence in solution and in the solid-state is still of high interest.…”

Section: Introductionmentioning

confidence: 99%

“…The structure of the 2-(2′-hydroxyphenyl) benzoxazole (HBO)-based ESIPT studied here is given in Figure 2. They featured mono-or bis-ethynyl extended trialkylsilyl moieties as these spacers have been reported to significantly enhance the photoluminescent quantum yield both in solution and in the solid-state [24]. The position of the alkynyl functionalization, as well as the nature of the alkyl group were modified in order to observe the influence of small structural modifications on the optical properties and RL efficiency.…”

Section: Introductionmentioning

confidence: 99%

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Natural Born Laser Dyes: Excited-State Intramolecular Proton Transfer (ESIPT) Emitters and Their Use in Random Lasing Studies

et al. 2019

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A series of five excited-state intramolecular proton transfer (ESIPT) emitters based on a 2-(2′-hydroxyphenyl) benzoxazole (HBO) scaffold, functionalized with a mono-or bis-(trialkylsilyl) acetylene extended spacer are presented. Investigation of their photophysical properties in solution and in the solid-state in different matrix, along with ab initio calculations gave useful insights into their optical behavior. Random lasing studies were conducted on a series of PMMA doped thin films, showing the presence of stimulated emission above the threshold of pumping energy density (ρth ≈ 0.5–2.6 mJ cm−2). In this work, the similarity of four level laser systems is discussed in light of the ESIPT photocycle.

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“…HBX heterocycles have been extensively used as highly emissive fluorophores due to a beneficial excited-state intramolecular proton transfer (ESIPT) photophysical process, paving the way to many innovative applications. [24,25] Alternatively, they are excellent chelates for a wide range of metallic or metalloid ions. [26][27][28] In this article, a series of cyclometalated iridium(III) complexes bearing a π-extended 2-(2-hydroxyphenyl) benzoxazole (HBO) ancillary ligand with terminal groups of different electronic nature (see Scheme 1) has been synthesized and their photophysical properties studied at room and low temperature.…”

Section: Introductionmentioning

confidence: 99%

Phosphorescent Cyclometalated Iridium(III) Complexes Bearing Ethynyl‐Extended 2‐(2'‐Hydroxyphenyl) Benzoxazole Ancillary Ligands

et al. 2020

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This article describes the synthesis and full photophysical studies at room and low temperature of a series of iridium(III) complexes incorporating an ethynyl-extended benzoxazole-based ancillary ligand. The electronic nature of the terminal end-group of the ancillary ligand was modulated by the simple introduction of electron-donating (Me, NBu 2 ) or -withdrawing (CN) groups. For all complexes, TD-DFT calculations showed that the lowest-lying transition was ligand-centered [a] Dr.Scheme 2. Synthesis of cyclometalated iridium(III) complexes 4-6 and 7-9. Results and Discussion SynthesisThe synthesis of the cyclometalated iridium(III) complexes 4-6 and 7-9 is presented on Scheme 2. The synthetic targets can be obtained straightforwardly in one step, starting from the previously reported 2-(2′-hydroxyphenyl)benzoxazole (HBO) ligands 1-3, [29] respectively functionalized by p-ethynyl-tolyl (R = Me), p-ethynyl-phenyl-N-dibutylamino (R = NBu 2 ) or p-ethynylbenzonitrile (R = CN) groups. The formation of the targeted cyclometalated iridium(III) complexes can be readily achieved by reacting the iridium(III) chloro-bridged dimers precursors A or B with two equivalents of HBO chelates 1-3, in the presence of an excess of potassium carbonate in a mixture of methanol and dichloromethane at 40°C (Scheme 2). Pure iridium(III) complexes were obtained in 47-72 % yield after purification on a silica gel column chromatography. All dimers were characterized with 1 H-NMR spectroscopy and high-resolution mass spectrometry (HR-MS), reflecting their molecular structure in each case. Formation of the targeted complexes 4-6 and 7-9 was notably confirmed by assessing the disappearance of the downfield H-bonded phenolic proton present in the molecular structure of starting HBO ligands 1-3 by 1 H-NMR spectroscopy. All spectra can be found in the Supporting Information (SI). As reported for other similar Ir (III) cyclometalated complexes, it is expected that complexes 4-9 adopt a distorted octahedral geometry with the nitrogen atoms of the pyridine moiety in trans position. [30] Absorption Absorption spectra of HBO ligands 1-3 and iridium(III) heteroleptic complexes 4-9, recorded in acetonitrile solution at room column chromatography on SiO 2 eluting with CH 2 Cl 2 /pet. ether to yield complexes 4-9 as yellow powders in 47-72 % yield. Complex 4: Yellow powder. 58 %. 1 H-NMR (400 MHz, CDCl 3 ) δ (ppm) = 8.74 (d, 1H, CH Ar, J = 5.2 Hz), 8.14 (d, 1H, CH Ar, J = 2.4 Hz), 8.02 (d, 1H, CH Ar, J = 5.6 Hz), 7.79 (d, 1H, CH Ar, J = 8 Hz), 7.72 (d, 1H, CH Ar, J = 8 Hz), 7.51-7.60 (m, 4H, CH Ar), 7.37 (d, 1H, CH Ar, J = 8 Hz), 7.32 (d, 2H, CH Ar, J = 8 Hz), 7.23 (dd, 1H, CH Ar, J = 9 Hz), 7.05-7.08 (m, 3H, CH Ar), 6.97 (t, 1H, CH Ar, J = 6 Hz), 6.68-6.87 (m, 6H, CH Ar), 6.62 (d, 1H, CH Ar, J = 9.2 Hz), 6.40 (d, 1H, CH Ar, J = 7.6 Hz), 6.11 (d, 1H, CH Ar, J = 7.6 Hz), 6.01 (d, 1H, CH Ar, J = 8.4 Hz), 2.28 (s, 3H, CH 3 ). ESI-HRMS: calcd. for C 44 H 31 IrN 3 O 2 [M + H] 826.2043, found [M + H] 826.2052. Complex 5: Yellow powder. 72 %. 1 H-NMR (400 MHz, ...

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Solution and solid-state Excited-State Intramolecular Proton Transfer (ESIPT) emitters incorporating Bis-triethyl-or triphenylsilylethynyl units

Cited by 37 publications

References 46 publications

Revelation of ESIPT mechanism for the novel fluorescent system HNIBT in toluene and methanol solvents: A TDDFT study

Revelation of ESIPT mechanism for the novel fluorescent system HNIBT in toluene and methanol solvents: A TDDFT study

Natural Born Laser Dyes: Excited-State Intramolecular Proton Transfer (ESIPT) Emitters and Their Use in Random Lasing Studies

Phosphorescent Cyclometalated Iridium(III) Complexes Bearing Ethynyl‐Extended 2‐(2'‐Hydroxyphenyl) Benzoxazole Ancillary Ligands

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