Nonlinear dependence of solvent polarity effects on twisted intramolecular charge-transfer states and linear relation for electronic spectra in a stilbazolium-like dye

2002 ◽  
Vol 147 (2) ◽  
pp. 93-101 ◽  
Author(s):  
Chuan-Lang Zhan ◽  
Duo-Yuan Wang
Keyword(s):  
Charge Transfer ◽  
Electronic Spectra ◽  
Linear Relation ◽  
Intramolecular Charge Transfer ◽  
Solvent Polarity ◽  
Nonlinear Dependence ◽  
Twisted Intramolecular Charge Transfer ◽  
Polarity Effects

Effect of bulky meso-substituents on photoinduced twisted intramolecular charge transfer processes in meso-diarylamino subporphyrins

2016 ◽  
Vol 20 (06) ◽  
pp. 663-669 ◽  
Author(s):  
Seung-Kyu Lee ◽  
Jun Oh Kim ◽  
Daiki Shimizu ◽  
Atsuhiro Osuka ◽  
Dongho Kim
Keyword(s):  
Charge Transfer ◽  
Intramolecular Charge Transfer ◽  
Solvent Polarity ◽  
Intramolecular Electron Transfer ◽  
Separation Processes ◽  
Time Resolved ◽  
Twisted Intramolecular Charge Transfer ◽  
Transfer Processes ◽  
Steady State Time ◽  
Photoexcited State

Photoexcited-state dynamics of meso-diarylamino subporphyrins 4–6 in cyclohexane, toluene, and acetonitrile have been studied by steady-state/time-resolved absorption and fluorescence experiments and quantum calculations. While 4 emits fluorescence from the locally excited state regardless of solvent polarity, the fluorescence of 5 and 6 are solvent-polarity dependent. The observed efficient fluorescent quenching of 5 and 6 has been ascribed to twisted intramolecular charge transfer (TICT), in which the two N–C[Formula: see text] bonds in 5 and the C[Formula: see text]–N bond in 6 are twisted to facilitate the intramolecular electron transfer. In 2-methyltetrahydrofuran (2-MeTHF), the fluorescence of 5 and 6 are both almost completely quenched at 297 K, but restored at 77 K (below the melting point of 2-MeTHF) because of the frozen molecular twisting. Furthermore, electrochemical studies also revealed the charge separation processes of 4–6 are thermally unfavorable in nonpolar toluene and cyclohexane unless their structures change contrary to the observed efficient fluorescence quenching. These observations support the TICT mechanism. In addition, the formation of TICT state is affected by steric effect as the size of the meso-substituents increases.

scholarly journals A Novel Dialkylamino GFP Chromophore as an Environment-Polarity Sensor Reveals the Role of Twisted Intramolecular Charge Transfer

Chemosensors ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 234
Author(s):  
Cheng Chen ◽  
Sean A. Boulanger ◽  
Anatolii I. Sokolov ◽  
Mikhail S. Baranov ◽  
Chong Fang
Keyword(s):  
Charge Transfer ◽  
Transient Absorption ◽  
Fluorescent Protein ◽  
Intramolecular Charge Transfer ◽  
Multivariable Analysis ◽  
Solvent Polarity ◽  
Dimethylamino Group ◽  
Twisted Intramolecular Charge Transfer

We discovered a novel fluorophore by incorporating a dimethylamino group (–NMe2) into the conformationally locked green fluorescent protein (GFP) scaffold. It exhibited a marked solvent-polarity-dependent fluorogenic behavior and can potentially find broad applications as an environment-polarity sensor in vitro and in vivo. The ultrafast femtosecond transient absorption (fs-TA) spectroscopy in combination with quantum calculations revealed the presence of a twisted intramolecular charge transfer (TICT) state, which is formed by rotation of the –NMe2 group in the electronic excited state. In contrast to the bright fluorescent state (FS), the TICT state is dark and effectively quenches fluorescence upon formation. We employed a newly developed multivariable analysis approach to the FS lifetime in various solvents and showed that the FS → TICT reaction barrier is mainly modulated by H-bonding capability instead of viscosity of the solvent, accounting for the observed polarity dependence. These deep mechanistic insights are further corroborated by the dramatic loss of fluorogenicity for two similar GFP-derived chromophores in which the rotation of the –NMe2 group is inhibited by structural locking.

scholarly journals Controlling the Twisted Intramolecular Charge-Transfer Character of Pyrene Derivatives Through Solvent Polarity

2021 ◽  
Author(s):  
Young Mo Sung ◽  
Eun Suk Kwon ◽  
Yusuke Makida Maruyama ◽  
Youngsik Shin ◽  
Soo-Ghang Ihn ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Structural Changes ◽  
Intramolecular Charge Transfer ◽  
Photophysical Properties ◽  
Critical Role ◽  
Solvent Polarity ◽  
Twisted Intramolecular Charge Transfer ◽  
Excited State Dynamics ◽  
Pyrene Derivatives

Abstract Intramolecular charge transfer (ICT) plays a critical role in determining the photophysical properties of organic molecules, including their luminescence efficiencies. Twisted intramolecular charge transfer (TICT) is a process in which structural change accompanies ICT. Despite significant research, the relationship between TICT and solvent polarity, and its effects on photophysical properties, have been rarely investigated. Herein, we used time-resolved spectroscopy to study TICT in pyrene derivatives that are promising blue organic light emitting diode (OLED) emitter candidates; these derivatives show strong solvent-dependent charge-transfer (CT) behavior. Slight structural changes that do not affect excited state dynamics were observed in nonpolar solvents, while polar solvents were found to affect excited state dynamics and CT characteristics. The TICT behavior of these pyrene derivatives could be modulated through structural modification. Our study provides valuable guidelines for the control of optical properties, including the luminescence efficiencies of OLED emitters that show TICT characteristics.

Dynamic adjustment of emission from both singlets and triplets: the role of excited state conformation relaxation and charge transfer in phenothiazine derivates

2021 ◽  
Author(s):  
Weidong Qiu ◽  
Xinyi Cai ◽  
Mengke Li ◽  
Liangying Wang ◽  
Yanmei He ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Intramolecular Charge Transfer ◽  
Dynamic Adjustment ◽  
Twisted Intramolecular Charge Transfer

Dynamic adjustment of emission behaviours by controlling the extent of twisted intramolecular charge transfer character in excited state.

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