Effect of solvent environment on the Photophysics of a newly synthesized bioactive 7-oxy(5-selenocyanato-pentyl)-2H-1-benzopyran-2-one

Solvent-dependent electronic structures of selected donor (D)-acceptor (A) phenanthrimidazole derivatives containing styryl as an electron acceptor fragment in fluorescent charge transfer (CT) states have been investigated. Radiative charge recombination [CT / S 0 ] is discussed in terms of the Mulliken-Murrell model of the CT complexes and the Marcus theory of photoinduced electron transfer (ET). Solvatochromic effects on the fluorescence spectra indicate the CT character of the emitting singlet states and the analysis leads to the electron transfer in the Marcus inverted region. The fluorescence rate constants (k r ) and transition dipole moments (M) indicate that the electronic coupling between the emitting CT state and the ground state is a governing factor of the radiative transitions. Large values of M indicate a nonorthogonal geometry (confirmed by XRD) of the donor and acceptor subunits in the fluorescent states. Emission spectra of N,N-dimethyl-4-(2-styryl-1H-phenanthro[9,10-d]imidazol-1-yl)benzenamine is of interest because of the existence of dual emitting states where a locally excited state is responsible for fluorescence in nonpolar solvents. In polar solvents fluorescence is from a twisted intramolecular charge transfer (TICT) state. Density functional theory (DFT) calculations support the formation of the TICT state. The twist of the -N(CH 3 ) 2 group and the change in its hybridization in the excited state develops a high dipole moment and thereby stabilizes it to give the TICT fluorescence in polar solvents.

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“…It may be that the hydrogen bonding interaction in polar protic environment enhances the stabilization of the excited state. 27…”

Section: Radiative and Non-radiative Rate Constantsmentioning

confidence: 99%

Photophysical properties of the intramolecular excited charge-transfer states of π-expanded styryl phenanthrimidazoles – effect of solvent polarity

et al. 2014

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“…It indicates that the radiative and non-radiative rates are more sensitive toward protic solvents. It may be that the hydrogen bonding interaction in polar protic environment enhances the stabilization of the S 1 state as a result the non-radiative relaxation rate increases [27].…”

Section: Solvent Modulated Absorption and Emission Behaviormentioning

confidence: 99%

Multiple Linear Regression Solvatochromic Analysis of Donar-Acceptor Imidazole Derivatives

et al. 2015

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Catalytic synthesis of some polysubstituted imidazoles under solvent-free condition is reported and their characterization has been carried out spectral techniques. Electronic spectral studies reveal that their solvatochromic behavior depends both the polarity of the medium and hydrogen bonding properties of the solvents. Specific hydrogen bonding interaction in polar solvents modulated the order of the two close lying lowest singlet states. The solvent effect on absorption and emission spectral results has been analyzed by multiple parametric regression analysis. Solvatochromic effects on the emission spectral position indicate the charge transfer (CT) character of the emitting singlet states both in a polar and a non polar environment. The fluorescence decays for the imidazoles fit satisfactorily to a bi exponential kinetics. These observations are in consistent with quantum chemical calculations.

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“…The energy trends of the same band for In1 in solvents are found to follow the order CHCl 3 ≈ CH 3 OH b CH 3 CN b DMSO. The observed blue-shift phenomenon might be attributed to the presence of a highly polarized ground state [42]. Although CH 3 OH possesses a much stronger polarity than CHCl 3 , the fluorescence spectra in these two solvents are almost the same.…”

mentioning

confidence: 93%

Auxiliary ligand-assisted two novel one-dimensional indium coordination polymers: Synthesis, crystal structures and photoluminescence characterization effected by solvent and temperature

Wang

Fan

Wang

et al. 2015

Inorganic Chemistry Communications

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Effect of solvent environment on the Photophysics of a newly synthesized bioactive 7-oxy(5-selenocyanato-pentyl)-2H-1-benzopyran-2-one

Cited by 27 publications

References 28 publications

Photophysical properties of the intramolecular excited charge-transfer states of π-expanded styryl phenanthrimidazoles – effect of solvent polarity

Photophysical properties of the intramolecular excited charge-transfer states of π-expanded styryl phenanthrimidazoles – effect of solvent polarity

Multiple Linear Regression Solvatochromic Analysis of Donar-Acceptor Imidazole Derivatives

Auxiliary ligand-assisted two novel one-dimensional indium coordination polymers: Synthesis, crystal structures and photoluminescence characterization effected by solvent and temperature

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