scholarly journals A theoretical study about the excited state intermolecular proton transfer mechanisms for 2-phenylimidazo[4,5-b]pyridine in methanol solvent

RSC Advances ◽  
2017 ◽  
Vol 7 (54) ◽  
pp. 34034-34040 ◽  
Author(s):  
Dapeng Yang ◽  
Jinfeng Zhao ◽  
Min Jia ◽  
Xiaoyan Song
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Theoretical Study ◽  
Dynamical Behavior ◽  
The Novel ◽  
Intermolecular Proton Transfer ◽  
System 2 ◽  
Transfer Mechanisms

Within the framework of DFT and TDDFT methods, we have investigated the novel system 2-phenylimidazo[4,5-b]pyridine (PIP) with respect to the dynamical behavior of its excited state in methanol (MeOH) solvents.

scholarly journals A Solvent-Mediated Excited-State Intermolecular Proton Transfer Fluorescent Probe for Fe3+ Sensing and Cell Imaging

Molecules ◽  
2022 ◽  
Vol 27 (2) ◽  
pp. 516
Author(s):  
You Qian ◽  
Fuchun Gong ◽  
Jiguang Li ◽  
Pan Ma ◽  
Hanming Zhu ◽  
...  
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Fluorescent Probe ◽  
Cell Imaging ◽  
Cyano Group ◽  
Proton Donor ◽  
Cell Permeability ◽  
One Pot ◽  
Intermolecular Proton Transfer ◽  
Synthesis Strategy

Constructing excited-state intermolecular proton transfer (ESIPT-e) fluorophores represents significant challenges due to the harsh requirement of bearing a proton donor-acceptor (D-A) system and their matching proton donating-accepting ability in the same molecule. Herein, we synthesized a new-type ESIPT-e fluorophor (2-APC) using the “four-component one-pot” reaction. By the installing of a cyano-group on pyridine scaffold, the proton donating ability of -NH2 was greatly enhanced, enabling 2-APC to undergo ESIPT-e process. Surprisingly, 2-APC exhibited dual-emissions in protic solvents ethanol and normal fluorescence in aprotic solvents, which is vastly different from that of conventional ESIPT-a dyes. The ESIPT emission can be obviously suppressed by Fe3+ due to the coordination reaction of Fe3+ with the A-D system in 2-APC. From this basis, a highly sensitive and selective method was established using 2-APC as a fluorescent probe, which offers the sensitive detection of Fe3+ ranging from 0 to 13 μM with the detection limit of 7.5 nM. The recovery study of spiked Fe3+ measured by the probe showed satisfactory results (97.2103.4%) with the reasonable RSD ranging from 3.1 to 3.8%. Moreover, 2-APC can also exhibit aggregation-induced effect in poor solvent or solid-state, eliciting strong red fluorescence. 2-APC was also applied to cell-imaging, exhibiting good cell-permeability, biocompatibility and color rendering. This multi-mode emission of 2-APC is significant departure from that of conventional extended p-conjugated systems and ESIPT dyes based on a flat and rigid molecular design. The “one-pot synthesis” strategy for the construction of ESIPT molecules pioneered a new route to achieve tricolor-emissive fluorophores.

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