scholarly journals Quantifying internal charge transfer and mixed ion-electron transfer in conjugated radical polymers

2020 ◽  
Vol 11 (36) ◽  
pp. 9962-9970 ◽  
Author(s):  
Shaoyang Wang ◽  
Alexandra D. Easley ◽  
Ratul M. Thakur ◽  
Ting Ma ◽  
Junyeong Yun ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Charge Transfer ◽  
Internal Electron ◽  
Internal Charge Transfer ◽  
Internal Charge

Conjugated radical polymers can exhibit internal electron transfer depending on the radical loading.

1,3,5-Triarylpyrazolines — pH-driven off-on-off molecular logic devices based on a “receptor1-fluorophore-spacer-receptor2” format with internal charge transfer (ICT) and photoinduced electron transfer (PET) mechanisms

2015 ◽  
Vol 93 (2) ◽  
pp. 199-206 ◽  
Author(s):  
Ramon Zammit ◽  
Maria Pappova ◽  
Esther Zammit ◽  
John Gabarretta ◽  
David C. Magri
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Charge Transfer ◽  
Photoinduced Electron Transfer ◽  
Photophysical Properties ◽  
Molecular Probes ◽  
Quantum Yields ◽  
Ph Sensing ◽  
Internal Charge Transfer ◽  
Internal Charge

The excited state photophysical properties of the 1,3,5-triarylpyrazolines 1–4 were studied in methanol and 1:1 (v/v) methanol–water, as well as 1:4 (v/v) methanol–water and water by fluorescence spectroscopy. The molecules 2–4 incorporate a “receptor1-fluorophore-spacer-receptor2” format while 1 is a reference compound based on a “fluorophore-receptor1” design. The molecular probes operate according to photoinduced electron transfer (PET) and internal charge transfer (ICT) processes. At basic and neutral pHs, 2–4 are essentially nonfluorescent due to PET from the electron-donating dimethylamino moiety appended on the 5-phenyl ring to the excited state of the 1,3,5-triarylpyrazoline fluorophore. At proton concentrations of 10−3 mol/L, the dimethylamino unit is protonated resulting in a strong blue fluorescence about 460 nm with significant quantum yields up to 0.54. At acid concentrations above 10−2 mol/L, fluorescence quenching is observed by an ICT mechanism due to protonation of the pyrazoline chromophore. Symmetrical off-on-off fluorescence–pH profiles are observed, spanning six log units with a narrow on window within three pH units. Hence, 2–4 are novel examples of ternary photonic pH sensing molecular devices.

A benzothiazole-based fluorescence turn-on sensor for copper(II)

2021 ◽  
Author(s):  
Gyeongjin Kim ◽  
Donghwan Choi ◽  
Cheal Kim
Keyword(s):  
Charge Transfer ◽  
Limit Of Detection ◽  
Theoretical Calculations ◽  
Enhanced Fluorescence ◽  
Turn On ◽  
Fluorescent Response ◽  
Chelation Enhanced Fluorescence ◽  
Fluorescence Turn On ◽  
Internal Charge Transfer ◽  
Internal Charge

Abstract A new benzothiazole-based chemosensor BTN (1-((Z)-(((E)-3-methylbenzo[d]thiazol-2(3H)-ylidene)hydrazono)methyl)naphthalen-2-ol) was synthesized for the detection of Cu2+. BTN could detect Cu2+ with “off-on” fluorescent response from colorless to yellow irrespective of presence of other cations. Limit of detection for Cu2+ was determined to be 3.3 µM. Binding ratio of BTN and Cu2+ turned out to be a 1:1 with the analysis of Job plot and ESI-MS. Sensing feature of Cu2+ by BTN was explained with theoretical calculations, which might be owing to internal charge transfer and chelation-enhanced fluorescence processes.

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