EXCITED-STATE INTRAMOLECULAR ELECTRON TRANSFER COUPLED WITH EXCITED-STATE INTRAMOLECULAR PROTON TRANSFER IN PHOTOINDUCED ENOL TO KETO TAUTOMERIZATION

2009 ◽  
Vol 08 (supp01) ◽  
pp. 1073-1086
Author(s):  
YUANZUO LI ◽  
SHASHA LIU ◽  
LILI ZHAO ◽  
MAODU CHEN ◽  
FENGCAI MA ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Charge Transfer ◽  
Proton Transfer ◽  
Molecular Orbital ◽  
Energy Levels ◽  
Three Dimensional ◽  
Intramolecular Proton Transfer ◽  
Intramolecular Electron Transfer ◽  
Lowest Unoccupied Molecular Orbital

In this paper, the two-dimensional (2D) site and the three-dimensional (3D) cube representations [Sun MT, J Chem Phys124: 054903, 2006] have been further developed to study the charge transfer during excited-state relaxation. With these newly developed representations, we theoretically investigate the excited-state intramolecular electron transfer (ESIET) in enol excited-state geometry relaxation, and ESIET coupled with excited-state intramolecular proton transfer (ESIPT) in phototautomerization (in enol to keto transformation). The energy levels of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of HBODC in enol and keto absorption and fluorescence are compared to understand photoinduced ESIET and ESIPT process. The excited regions of molecule (where arrangement of electron density takes place during excited-state relaxation) are located with 2D site representation. 3D cube representations visualize the character of charge transfer (CT) in those regions. Results of the research indicate that the ability of charge transfer during enol excited-state geometry relaxation is much stronger than that in phototautomerization.

scholarly journals Ingenious modification of molecular structure effectively regulates excited-state intramolecular proton and charge transfer: a theoretical study based on 3-hydroxyflavone

RSC Advances ◽  
2018 ◽  
Vol 8 (52) ◽  
pp. 29589-29597 ◽  
Author(s):  
Jianhui Han ◽  
Xiaochun Liu ◽  
Chaofan Sun ◽  
You Li ◽  
Hang Yin ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Excited State ◽  
Charge Transfer ◽  
Proton Transfer ◽  
Theoretical Study ◽  
Intramolecular Charge Transfer ◽  
Intramolecular Proton Transfer ◽  
Great Promise ◽  
Fluorescence Sensing

Harnessing ingenious modification of molecular structure to regulate excited-state intramolecular proton transfer (ESIPT) and intramolecular charge transfer (ICT) characteristics holds great promise in fluorescence sensing and imaging.

Synthesis, crystal structure and photophysical properties of 1,4-bis(1,3-diazaazulen-2-yl)benzene: a new π building block

2018 ◽  
Vol 74 (2) ◽  
pp. 171-176
Author(s):  
Peili Sun ◽  
Zongyao Zhang ◽  
Hongxia Luo ◽  
Pu Zhang ◽  
Yujun Qin ◽  
...  
Keyword(s):  
Molecular Orbital ◽  
Building Block ◽  
Photophysical Properties ◽  
Condensation Reaction ◽  
Energy Levels ◽  
Three Dimensional ◽  
Experimental Result ◽  
Monoclinic System ◽  
H Nmr ◽  
Lowest Unoccupied Molecular Orbital

A dimerized 1,3-diazaazulene derivative, namely 1,4-bis(1,3-diazaazulen-2-yl)benzene [or 2,2′-(1,4-phenylene)bis(1,3-diazaazulene)], C22H14N4, (I), has been synthesized successfully through the condensation reaction between 2-methoxytropone and benzene-1,4-dicarboximidamide hydrochloride, and was characterized by 1H NMR and 13C NMR spectroscopies, and ESI–MS. X-ray diffraction analysis reveals that (I) has a nearly planar structure with good π-electron delocalization, indicating that it might serve as a π building block. The crystal belongs to the monoclinic system. One-dimensional chains were formed along the a axis through π–π interactions and adjacent chains are stabilized by C—H...N interactions, forming a three-dimensional architecture. The solid emission of (I) in the crystalline form exhibited a 170 nm red shift compared with that in the solution state. The observed optical bandgap for (I) is 3.22 eV and a cyclic voltammetry experiment confirmed the energy levels of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO). The calculated bandgap for (I) is 3.37 eV, which is very close to the experimental result. In addition, the polarizability and hyperpolarizability of (I) were appraised for its further application in second-order nonlinear optical materials.

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