Hydroxy-benzimidazoles as blue-green emitters: Synthesis, structural and DFT studies

Sathyanarayana, Reshma; Kumar, Vasantha; Pujar, G. H.; Poojary, Boja; Shankar, Madan Kumar; Sangappa, Y.

doi:10.1016/j.jphotochem.2020.112751

Cited by 11 publications

(9 citation statements)

References 47 publications

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“…33,34 Barriers on the potential energy curve of the excited state can partially or fully frustrate the ESIPT photo-reaction, leading to dual emission or to the emission of the normal form only. [35][36][37][38][39][40][41] Following the emission of the tautomeric form, the proton transfers to its original position (ground state intramolecular proton transfer, GSIPT), which restores the normal form (Scheme 1).…”

Section: Introductionmentioning

confidence: 99%

Tuning ESIPT-coupled luminescence by expanding π-conjugation of a proton acceptor moiety in ESIPT-capable zinc(ii) complexes with 1-hydroxy-1H-imidazole-based ligands

et al. 2022

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Section: Introductionmentioning

confidence: 99%

Tuning ESIPT-coupled luminescence by expanding π-conjugation of a proton acceptor moiety in ESIPT-capable zinc(ii) complexes with 1-hydroxy-1H-imidazole-based ligands

et al. 2022

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“…In the case of barriers on excited state potential energy surfaces, the molecule can be trapped in a local minimum of the normal form, leading to the emission of the normal form. Modifying the barrier height in the excited state, one can achieve dual emission associated with the luminescence of both forms [ 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 ]. The sensitivity of ESIPT-capable compounds to various stimuli makes them an appealing platform for numerous applications [ 67 , 68 , 69 ].…”

Section: Introductionmentioning

confidence: 99%

ESIPT-Capable 4-(2-Hydroxyphenyl)-2-(Pyridin-2-yl)-1H-Imidazoles with Single and Double Proton Transfer: Synthesis, Selective Reduction of the Imidazolic OH Group and Luminescence

et al. 2023

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1H-Imidazole derivatives establish one of the iconic classes of ESIPT-capable compounds (ESIPT = excited state intramolecular proton transfer). This work presents the synthesis of 1-hydroxy-4-(2-hydroxyphenyl)-5-methyl-2-(pyridin-2-yl)-1H-imidazole (LOH,OH) as the first example of ESIPT-capable imidazole derivatives wherein the imidazole moiety simultaneously acts as a proton acceptor and a proton donor. The reaction of LOH,OH with chloroacetone leads to the selective reduction of the imidazolic OH group (whereas the phenolic OH group remains unaffected) and to the isolation of 4-(2-hydroxyphenyl)-5-methyl-2-(pyridin-2-yl)-1H-imidazole (LH,OH), a monohydroxy congener of LOH,OH. Both LOH,OH and LH,OH demonstrate luminescence in the solid state. The number of OH···N proton transfer sites in these compounds (one for LH,OH and two for LOH,OH) strongly affects the luminescence mechanism and color of the emission: LH,OH emits in the light green region, whereas LOH,OH luminesces in the orange region. According to joint experimental and theoretical studies, the main emission pathway of both compounds is associated with T1 → S0 phosphorescence and not related to ESIPT. At the same time, LOH,OH also exhibits S1 → S0 fluorescence associated with ESIPT with one proton transferred from the hydroxyimidazole moiety to the pyridine moiety, which is not possible for LH,OH due to the absence of the hydroxy group in the imidazole moiety.

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“…However, if kinetic barriers are high enough to impede the ESIPT photoreaction, the N-form of the molecule can emit itself and can produce dual emission associated with the emission of both forms of the molecule. [21][22][23][24][25][26][27][28][29][30][31] Furthermore, the emission of ESIPT-dyes often involves triplet excited states, giving rise to phosphorescence (including room temperature phosphorescence) and thermally-activated delayed fluorescence. [32][33][34][35][36][37][38][39][40][41] This plethora of emissive excited states makes ESIPT-capable compounds an appealing platform for the design of multicolor luminescent materials.…”

Section: Introductionmentioning

confidence: 99%

Luminescence of ESIPT-capable zinc(ii) complexes with a 1-hydroxy-1H-imidazole-based ligand: exploring the impact of substitution in the proton-donating moiety

et al. 2023

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Hydroxy-benzimidazoles as blue-green emitters: Synthesis, structural and DFT studies

Cited by 11 publications

References 47 publications

Tuning ESIPT-coupled luminescence by expanding π-conjugation of a proton acceptor moiety in ESIPT-capable zinc(ii) complexes with 1-hydroxy-1H-imidazole-based ligands

Tuning ESIPT-coupled luminescence by expanding π-conjugation of a proton acceptor moiety in ESIPT-capable zinc(ii) complexes with 1-hydroxy-1H-imidazole-based ligands

ESIPT-Capable 4-(2-Hydroxyphenyl)-2-(Pyridin-2-yl)-1H-Imidazoles with Single and Double Proton Transfer: Synthesis, Selective Reduction of the Imidazolic OH Group and Luminescence

Luminescence of ESIPT-capable zinc(ii) complexes with a 1-hydroxy-1H-imidazole-based ligand: exploring the impact of substitution in the proton-donating moiety

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