Photochemical Processes in a Copolymer of 2-(2'-Hydroxy-4'-methacryloyloxyphenyl)-2H-benzotriazole and Methyl Methacrylate

1994 ◽  
Vol 47 (8) ◽  
pp. 1461 ◽  
Author(s):  
R Dux ◽  
KP Ghiggino ◽  
O Vogl
Keyword(s):  
Excited State ◽  
Methyl Methacrylate ◽  
Arrhenius Plot ◽  
Emission Spectra ◽  
Intramolecular Proton Transfer ◽  
Wavelength Band ◽  
Temperature Dependent ◽  
Short Wavelength Band ◽  
Intramolecular Hydrogen ◽  
Hydrogen Bonded

The temperature-dependent (10-300 K) fluorescence behaviour of films of a copolymer of 2-(2′-hydroxy-4′-methacryloyloxyphenyl)-2H-benzotriazole and methyl methacrylate (HMPB-co-MMA) has been studied. The emission spectra consist of a short-wavelength band and a highly Stokes-shifted emission with maxima at 390 and 550 nm respectively. The temperature- insensitive 390 nm emission is assigned to a non- intramolecular hydrogen-bonded form of HMPB while the red-shifted emission is due to the species formed following excited-state intramolecular proton transfer. The temperature dependence of the 550 nm fluorescence is complex and does not allow a linear Arrhenius plot. Possible mechanisms for the temperature-dependent deactivation processes are proposed. Irradiation studies indicate that the non-planar HMPB entities are more photolabile than the intramolecularly hydrogen-bonded form. The relevance of the results to the application of HMPB as an ultraviolet absorber and photostabilizer in polymers is discussed.

An analogy study on ESIPT reaction for 3BHC sensor between polar DMF and nonpolar toluene

2017 ◽  
Vol 95 (12) ◽  
pp. 1303-1307
Author(s):  
Dapeng Yang ◽  
Min Jia ◽  
Jingyuan Wu ◽  
Xiaoyan Song ◽  
Qiaoli Zhang
Keyword(s):  
Excited State ◽  
Density Functional ◽  
Emission Spectra ◽  
Dft Method ◽  
Intramolecular Proton Transfer ◽  
Nonpolar Solvent ◽  
State Behavior ◽  
Functional Theory ◽  
Td Dft ◽  
Intramolecular Hydrogen

A comparison about excited state intramolecular proton transfer (ESIPT) mechanism of a new sensor 3-(1,3-benzothiazol-2-yl)-2-hydroxynaphthalene-1-carbaldehyde (3BHC) in polar solvent dimethylformamide (DMF) and nonpolar solvent toluene have been investigated within the framework of the time-dependent density functional theory (TD-DFT) method. The reproduced previous experimental absorption and emission spectra via our calculations reveals the reasonability of the DFT and TD-DFT theoretical level. The staple bond lengths, bond angles, and corresponding infrared vibrational spectra demonstrate that the intramolecular hydrogen bond of 3BHC should be strengthened in both polar DMF and nonpolar toluene. Two kinds of ESIPT mechanisms for different solvents have been put forward; there is a low potential barrier in the ESIPT process in the DMF solvent, whereas there is almost a nonbarrier for the ESIPT process in the toluene solvent. Hence, we could conclude that the ESIPT process of 3BHC sensor is more likely to occur in the nonpolar solvent upon the photoexcitation, based on which, the excited state behavior of 3BHC could be controlled.

Excited-State Intramolecular Proton Transfer in Polymers

1995 ◽  
Vol 413 ◽  
Author(s):  
Richard M. Tarkka ◽  
Samson A. Jenekhe
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Main Chain ◽  
Intramolecular Proton Transfer ◽  
Polymer Structure ◽  
Laser Dyes ◽  
Excimer Formation ◽  
Photochromic Materials ◽  
Hydrogen Bonded

ABSTRACTExcited state intramolecular proton transfer (ESIPT) has been demonstrated in new intramoleculary hydrogen bonded (IHB) polymers of interest as photostabilizers, triplet quenchers, photochromic materials, laser dyes and electroluminescent materials. The new IHB polymers containing the 2-(2-hydroxyphenyl)benzoxazole moiety in the main chain were used to explore the effects of polymer structure, extended conjugation and competition with excimer formation on the ESIPT process. It was found that polymer structure, and particularly extent of conjugation, affects an IHB polymer's ability to exhibit ESIPT.

Effect of amino group on the excited-state intramolecular proton transfer (ESIPT) mechanisms of 2-(2′-hydroxyphenyl)benzoxazole and its amino derivatives

RSC Advances ◽  
2016 ◽  
Vol 6 (6) ◽  
pp. 5134-5140 ◽  
Author(s):  
Chaozheng Li ◽  
Yonggang Yang ◽  
Chi Ma ◽  
Yufang Liu
Keyword(s):  
Excited State ◽  
Hydrogen Bonds ◽  
Proton Transfer ◽  
Intramolecular Proton Transfer ◽  
Amino Group ◽  
Electronic Density ◽  
Intramolecular Hydrogen Bonds ◽  
Amino Derivatives ◽  
Intramolecular Hydrogen

The electronic density redistributes and it migrates in opposite directions for HBO when compared to those of 5A-HBO and 6A-HBO. The amino group in the HBO framework can change the behavior of the intramolecular hydrogen bonds.

Theoretical investigation on ESIPT mechanism for a novel Sal-3,4-benzophen system

2017 ◽  
Vol 16 (08) ◽  
pp. 1750073 ◽  
Author(s):  
Jian Lv ◽  
Dapeng Yang
Keyword(s):  
Excited State ◽  
Hydrogen Bonds ◽  
Potential Energy ◽  
Density Functional ◽  
Intramolecular Proton Transfer ◽  
Potential Energy Curves ◽  
State Process ◽  
The Density Functional Theory ◽  
Intramolecular Hydrogen ◽  
Excited State Process

In this work, we theoretically investigate the properties of excited state process for a novel salicylidene sal-3,4-benzophen (Sal-3,4-B) system, which contains two intramolecular hydrogen bonds (O1-H2[Formula: see text]N3 and O4-H5[Formula: see text]N6). Based on the density functional theory (DFT) and time-dependent DFT (TDDFT) methods, we find these two hydrogen bonds should be strengthened in the S1 state, while the O4-H5[Formula: see text]N6 one could be largely affected upon the excitation process. Analyses about infrared (IR) vibrational spectra about hydrogen bond moieties also confirm this viewpoint. Frontier molecular orbitals (MOs) depict the nature of electronic excited state and support the excited state intramolecular proton transfer (ESIPT) reaction.Two kinds of stepwise potential energy curves of Sal-3,4-B in the S1 state demonstrate that only one proton could be transferred. Also based on constructing potential energy curves, the synergetic situation could be eliminated. Due to the specific ESIPT mechanism for Sal-3,4-B, we successfully explain the previous experiment and provide a reasonable attribution to the second emission peak of experiment.

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