Environment sensitive phenothiazine dyes strongly fluorescence in protic solvents

Han, Feng; Chi, Liang; Wu, Wenting; Liang, Xiaofen; Fu, Mengying; Zhao, Jianzhang

doi:10.1016/j.jphotochem.2007.11.007

Cited by 60 publications

(62 citation statements)

References 35 publications

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“…The photophysical properties of PTZ-5 and PTZ-4 have been reported previously. 15 The properties are recalled here for a clearer discussion. PTZ-5 and PTZ-4 have similar structures except for the C 15 ÀC 16 bond (Figure 1).…”

Section: à32mentioning

confidence: 99%

“…As expected, a larger Storks' The Journal of Physical Chemistry B ARTICLE shift was found in the more polar solvent. 15 Subsequently, the dark state equilibrium populations will be decreased by increasing the solvent polarity; the bright state populations will be increased so that fluorescence is enhanced. This is in agreement with the results in Figure 2b showing that the quantum yields increase with the increase in solvent polarity.…”

Section: à32mentioning

confidence: 99%

“…15 The difference in structure between PTZ-5 and PTZ-4 is the C 15 ÀC 16 bond. PTZ-5 has a similar structure with uracil at NÀC 15 27 .…”

Section: à33mentioning

confidence: 99%

“…15 The difference in structure between PTZ-5 and PTZ-4 is the C 15 ÀC 16 bond. PTZ-5 has a similar structure with uracil at NÀC 15 27 . The potential energy profiles of GS and the nπ* and ππ* states are shown in Figure 5 (the excited states are actually the mixes between nπ* and ππ*; these are identified by the relevant MOs).…”

Section: à33mentioning

confidence: 99%

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Solvent Effects on 3-Keto-1H-pyrido[3,2,1-kl]phenothiazine Fluorescence in Polar and Protic Solvents

et al. 2011

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The photophysical and photochemical properties of fluorophores are always affected by solvents. 1À26 These include solvent polarity, viscosity, temperature, and specific solvent and fluorophore interaction. There are two kinds of solvent effects: the general and the specific solvent effects.1,2 General solvent effects are due to the interactions of the fluorophore dipole with its environment. Solvent polarity is a major factor of general solvent effects. For example, an internal charge-transfer (ICT) state was formed for coumarin-151 (C151) in a polar solvent. Compared with the local excited (LE) state, the ICT state has a smaller nonradiative decay rate (k nr ). Thus, the fluorescence of C151 in high-polarity solvents enhanced with the decrease of k nr .3 In contrast to C151, the ICT state of neutral red has a smaller radiative decay rate (k r ) compared with its LE state. Therefore, the fluorescence quantum yield of neutral red decreased in highpolarity solvents. 4 Specific solvent effects, which are produced by interactions between the fluorophore and neighboring solvent molecules, are more complex than general solvent effects. The fluorescence properties of C151 and neutral red in protic solvents are also affected by specific solvent effects.3,4 Excitedstate proton transfer (ESPT) is considered a very important reaction in the excited-state dynamics of fluorophore.5À11 Electron transfer between the solute and the solvent also affects the photophysical and photochemical properties of fluorophores.14 Actually, the solvent effects on the excited-state dynamics of fluorophores are essential to its photophysical and photochemical properties. Investigating solvent effects on excited-state dynamics helps one to understand the fluorescence properties of fluorophores. Numerous theoretic efforts have been made to describe the excited-state dynamics of fluorophores in different circumstances.11À13,27À33 The energy gap law is well established.27 Lim et al. explored a "proximity effect" model to understand the photophysical properties of nitrogen-hytero cyclic or aromatic carbonyl compounds. 12,13 Zgierski et al. found a biradical radiationless decay channel in natural bases. 29À32Recently, Han et al. reported some environment-sensitive phenothiazine dyes.15 Among these (Figure1) are 3-keto-1H-pyrido[3,2,1-kl]phenothiazine (PTZ-5) and 2,3-dihydro-3-keto-1H-pyrido[3,2,1-kl]phenothiazine (PTZ-4), both of which show interesting photophysical properties. In protic solvents, PTZ-5 has shown significantly higher fluorescence quantum yields than in aprotic solvents, whereas PTZ-4 was quenched entirely. However, the effects of solvent properties on the fluorescence properties of these two dyes remain unclear.This paper focuses on the solvent effects on PTZ-5 fluorescence properties. PTZ-4 was also investigated as a comparison. The time-dependent density functional theory (TD-DFT) method was used to investigate the electronic states of PTZ-5 and PTZ-4. The general solvent effects on the fluorescence properties of PTZ-5 and PTZ-4...

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Section: à32mentioning

confidence: 99%

Section: à32mentioning

confidence: 99%

“…15 The difference in structure between PTZ-5 and PTZ-4 is the C 15 ÀC 16 bond. PTZ-5 has a similar structure with uracil at NÀC 15 27 .…”

Section: à33mentioning

confidence: 99%

Section: à33mentioning

confidence: 99%

See 2 more Smart Citations

Solvent Effects on 3-Keto-1H-pyrido[3,2,1-kl]phenothiazine Fluorescence in Polar and Protic Solvents

et al. 2011

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“…Han et al recently reported several phenothiazine derivative dyes as environment-sensitive fluorescence probes [29], finding that 2,3-dihydro-3-keto-1H-pyrido[3,2,1-kl]phonothiazine (PTZ4) and 3-keto-1H-pyrido[3,2,1-kl]phenothiazine (PTZ5) have similar fluorescence intensities in aprotic solvents. However, the fluorescence of PTZ4 was quenched, whereas that of PTZ5 was enhanced in protic solvents.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen Bonding Effects on the Photophysical Properties of 2,3-dihydro-3-keto-1H-pyrido[3,2,1-kl]phenothiazine

Yang

2012

Chinese Journal of Chemical Physics

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Time-dependent density functional theory (TDDFT) and femtosecond transient absorption spectroscopy were used to investigate the photophysical properties of 2,3-dihydro-3-keto-1H-pyrido[3,2,1-kl]phenothiazine (PTZ4) and 3-keto-1H-pyrido[3,2,1-kl]phenothiazine (PTZ5). The calculated results obtained from TDDFT suggest that the red-shifts of the absorption spectra of these two fluorophores in methanol are due to the formation of hydrogen-bonded complexes at the ground state. Four conformers of PTZ4 were obtained by TDDFT. The two fluorescence peaks of PTZ4 in tetrahydrofuran (THF) came from the ICT states of the four conformers. The fluorescence of PTZ4 in THF showed a dependence on the excitation wavelength because of butterfly bending. The excited state dynamics of PTZ4 in THF and methanol were obtained by transient absorption spectroscopy. The lifetime of the excited PTZ4 in methanol was 53.8 ps, and its relaxation from the LE state to the ICT state was completed within several picoseconds. The short lifetime of excited PTZ4 in methanol was due to the formation of out-of-plane model hydrogen bonds between PTZ4 and methanol at the excited state.

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Solute–Solvent Hydrogen Bond Formation in the Excited State. Experimental and Theoretical Evidence

Matei

Ionescu

Hillebrand

2010

Hydrogen Bonding and Transfer in the Excited State

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Hydrogen bonds (H-bonds) are of great importance in biological systems, as they are responsible for the secondary structure of proteins and nucleic acids and are also involved in the mechanisms of enzyme catalysis. Supramolecular chemistry makes use of H-bonds in building up novel compounds of various architectures.The identification of these interactions and the analysis of their influence on the photophysical properties are also important in designing new fluorophores for different applications, the processes involved being rather complex in nature and often only partially understood.The main feature reflecting H-bond interaction in both the ground and excited states is the solvatochromic effect on the absorption and fluorescence spectra. This implies that changes in the solvent nature or composition produce shifts in the position, shape and intensity of the spectral bands. The source of solvatochromic shifts is the different solvation of the ground and excited states: depending on the relative stabilization of these states by solvents, bathochromic (positive)or hypsochromic (negative)shifts of the maximum of the band can be observed experimentally. Thus, such changes are indicative of the interactions occurring between the solute and the solvent in its immediate vicinity. The solute-solvent interactions are classified into:1. non-specific interactions caused by polarity/polarizability effects; 2. specific interactions, such as H-bonds.

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Environment sensitive phenothiazine dyes strongly fluorescence in protic solvents

Cited by 60 publications

References 35 publications

Solvent Effects on 3-Keto-1H-pyrido[3,2,1-kl]phenothiazine Fluorescence in Polar and Protic Solvents

Solvent Effects on 3-Keto-1H-pyrido[3,2,1-kl]phenothiazine Fluorescence in Polar and Protic Solvents

Hydrogen Bonding Effects on the Photophysical Properties of 2,3-dihydro-3-keto-1H-pyrido[3,2,1-kl]phenothiazine

Solute–Solvent Hydrogen Bond Formation in the Excited State. Experimental and Theoretical Evidence

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