Study on the synthesis and structure–effect relationship of multi‐aryl imidazoles with their fluorescence properties

Tian, Mi; Wang, Chao; Wang, LiGong; Luo, Kai; Zhao, An; Guo, Can‐Cheng

doi:10.1002/bio.2580

Cited by 21 publications

(11 citation statements)

References 38 publications

(42 reference statements)

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“…Blue fluorescent phenanthroimidazole derivative, 1,4bis(1H-phenanthro [9,10-d]imidazol-2-yl)benzene (BPIB), is known to show high luminescence efficiency in solution due to the rigid and π-conjugated molecular structure. 62,63 However, fluorescence is completely diminished in the aggregated or solid-state. The optimized structure of BPIB showed the planar geometry, which could lead to the π-π stacking interactions in the aggregated state, quenching the fluorescence.…”

Section: Resultsmentioning

confidence: 99%

Unraveling Molecular Assembly and Tracking Lipid Droplets Dynamics using Fluorescent Phenanthroimidazole Derivatives

Kundu

Saha

et al. 2022

Preprint

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A judicious structural modification of molecular building units imparts significant variation in the evolution dynamics of supramolecular self-assembled architectures and their functional properties. The incorporation of alkyl chains into the rigid and π-conjugated molecular backbone not only directs the self-assembly but also enhances the hydrophobicity of the probe, facilitating specific interactions with hydrophobic organelle like lipid droplets (LDs). Such a fluorescent molecular probe is ideally suited for elucidation of complex self-assembly processes and to decipher the intracellular dynamics of LDs. Invoking the concept, the main skeleton of 1,4-bis(1H-phenanthro[9,10-d]imidazol-2-yl)benzene abbreviated as BPIB, was functionalized with a varying number of octyl chains to obtain BPIB1 and BPIB2. The alkyl chains were crucial to circumvent the π-π stacking leading to the strong fluorescence in aggregates and solid-state. Contrary to BPIB and BPIB2, intermolecular interactions-driven spontaneous self-association of BPIB1 having an amine nitrogen center and a long alkyl chain resulted in a stimuli-responsive fluorescent organogel. We deciphered the reversible morphological transformation between supramolecular fibers and spherical nanoaggregates using fluorescence lifetime imaging microscopy. The gradual progression in the fluorescence lifetime provides a unique strategy for exploring the dynamics of the self-assembly process. Furthermore, BPIB1 was found to be a specific marker for LDs in multiple cell lines. The fluorescence correlation spectroscopy revealed the microenvironments near LDs. Highly photostable BPIB1 was employed for the real-time tracking of the LDs dynamics in live cells. Thus, a combined microscopic and spectroscopic approach demonstrated in the present study opens up new avenues for further exploration of intriguing molecular aggregation and intracellular dynamics.

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Section: Resultsmentioning

confidence: 99%

Unraveling Molecular Assembly and Tracking Lipid Droplets Dynamics using Fluorescent Phenanthroimidazole Derivatives

Kundu

Saha

et al. 2022

Preprint

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“…A similar observation was reported previously for fluorescent imidazole‐based emitters. [ 28 ] Owing to the larger size of the Ph and t Bu substituents compared to the parent and methylated structures, the torsion angle, α, deviates from the usually favorable α = 0°–19.5° and 40.8°, respectively, which in turn disrupts conjugation between the BIm and Py heterocycles, increasing the C BIm –C Py bond length slightly (Table S5, Supporting Information). A consequence of this conformational change is a predicted increase in the LUMO energy.…”

Section: Resultsmentioning

confidence: 99%

“…The destabilization is more pronounced in BIm( t Bu)PyPXZ as the inductively electron‐withdrawing phenyl group in BIm(Ph)PyPXZ counteracts the decrease in conjugation due to this bulky substituent. [ 28 ] In each example there is very little change in the Highest Occupied Molecular Orbital (HOMO) level, which is localized on the PXZ. HOMO to LUMO transitions dominate vertical excitations to the S 1 while the T 1 state is a more complex picture involving several different transitions (Table S7, Supporting Information).…”

Section: Resultsmentioning

confidence: 99%

Substitution Effects on a New Pyridylbenzimidazole Acceptor for Thermally Activated Delayed Fluorescence and Their Use in Organic Light‐Emitting Diodes

Hall

Rajamalli

Du̅da

et al. 2021

Advanced Optical Materials

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In this work a new acceptor is used for use in thermally activated delayed fluorescence (TADF) emitters, pyridylbenzimidazole, which when coupled with phenoxazine allows efficient TADF to occur. N‐functionalization of the benzimidazole using methyl, phenyl, and tert‐butyl groups permits color tuning and suppression of aggregation‐caused quenching (ACQ) with minimal impact on the TADF efficiency. The functionalized derivatives support a higher doping of 7 wt% before a fall‐off in photoluminescence quantum yields is observed, in contrast with the parent compound, which undergoes ACQ at doping concentrations greater than 1 wt%. Complex conformational dynamics, reflected in the time‐resolved decay profile, is found. The singlet−triplet energy gap, ΔEST, is modulated by N‐substituents of the benzimidazole and ranges of between 0.22 and 0.32 eV in doped films. Vacuum‐deposited organic light‐emitting diodes, prepared using three of the four analogs, show maximum external quantum efficiencies, EQEmax, of 23.9%, 22.2%, and 18.6% for BIm(Me)PyPXZ, BIm(Ph)PyPXZ, and BImPyPXZ, respectively, with a correlated and modest efficiency roll‐off at 100 cd m–2 of 19% 13%, and 24% of the EQEmax, respectively.

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“…Scheme 1 depicts the synthetic procedure for the preparation of compounds 1a – 1c according to previous studies [ 42 , 43 ]. The two adjacent phenyl rings of compound 1a were connected through C–C bond to form compound 1b , which exhibited a rigid structure and high degree of coplanarity, to investigate the relationship between molecular structures and optical behaviors.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Bisimidazole Derivatives for Selective Sensing of Fluoride Ion

Zhang

Liu

2017

Molecules

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Rapid and efficient analysis of fluoride ion is crucial to providing key information for fluoride ion hazard assessment and pollution management. In this study, we synthesized one symmetrical structure called 1,4-bis(4,5-diphenyl-1H-imidazol-2-yl)benzene (1a) and two asymmetrical structures, namely 2-(4-(4,5-diphenyl-1H-imidazol-2-yl)phenyl)-1H-phenanthro(9,10-d)imidazole (1b) and 2-(4-(4,5-diphenyl-1H-imidazol-2-yl)phenyl)-1H-imidazo(4,5-f)(1,10)phenanthroline (1c), which served as an efficient anion sensor for fluoride ion over a wide range of other anions (Cl−, Br−, I−, NO3−, ClO4−, HSO4−, BF4−, and PF6−) owing to imidazole group in the main backbone. The absorption intensity of compound 1a at λmax 358 nm slightly decreased; however, a new band at λmax 414 nm appeared upon the addition of fluoride ion, while no evident change occurred upon the addition of eight other anions. The photoluminescence intensity of compound 1a at λmax 426 nm was nearly quenched and fluorescence emission spectra were broadened when fluoride ion was added into dimethyl sulfoxide (DMSO) solution of compound 1a. Compared with the optical behaviors of the DMSO solution of compound 1a in the presence of Bu4N+F−, compounds 1b and 1c exhibited considerable sensitivity to fluoride ion due to the increase in coplanarity. Furthermore, compared with the fluorescence emission behaviors of the DMSO solutions of compounds 1a and 1b in the presence of Bu4N+F−, compound 1c exhibited the most significant sensitivity to fluoride ion due to the charge transfer enhancement. Consequently, the detection limits of compounds 1a–1c increased from 5.47 × 10−6 M to 4.21 × 10−6 M to 9.12 × 10−7 M. Furthermore, the largest red shift (75 nm) of the DMSO solution compound 1c in the presence of fluoride ion can be observed. Our results suggest that the increase in coplanarity and the introduction of electron-withdrawing groups to the imidazole backbone can improve the performance in detecting fluoride ion.

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Study on the synthesis and structure–effect relationship of multi‐aryl imidazoles with their fluorescence properties

Cited by 21 publications

References 38 publications

Unraveling Molecular Assembly and Tracking Lipid Droplets Dynamics using Fluorescent Phenanthroimidazole Derivatives

Unraveling Molecular Assembly and Tracking Lipid Droplets Dynamics using Fluorescent Phenanthroimidazole Derivatives

Substitution Effects on a New Pyridylbenzimidazole Acceptor for Thermally Activated Delayed Fluorescence and Their Use in Organic Light‐Emitting Diodes

Synthesis of Bisimidazole Derivatives for Selective Sensing of Fluoride Ion

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