Theoretical study on influence of geometries controlling over the excited-state intramolecular proton transfer of 10-hydroxybenzo[h]quinoline and its derivatives as fluorescent probe

การศึกษาเชิงทฤษฎีเกี่ยวกับอิทธิพลของโครงสร้างที่ควบคุมการถ่ายโอนโปรตอนภายในโมเลกุลที่สภาวะกระตุ้นของ 10-ไฮดรอกซีเบนโซ[เอช]ควิโนลีนและอนุพันธ์ที่ใช้เป็นตัววัดเรืองแสง

Name: Warinthon Chansen

ThaSH: Molecules

Classification :.DDC: 547.869

ThaSH: Protons

Abstract: Excited state intramolecular proton transfer (ESIPT) process is an important process in chemical and biological systems. ESIPT process generally occurs in molecules having proton donor and proton acceptor, providing four-level photocycle. Among ESIPT molecules, 10-hydroxybenzo[h]quinoline (HBQ) has been used as a radiation hardscintillator, probe enzyme, and photoswitch based on its highly large Stokes shift between absorption and emission spectra and high photostability. HBQ comprises quinoline and phenol groups which form a strong intramolecular hydrogen bond, facilitating proton transfer upon photoexitation. The structural modification on quinoline of HBQ greatly change its photophysical properties. Therefore, in this work, the photophysical changes of HBQ derivatives affected by structural modification on quinoline and ESIPT process will be investigated using a hybrid density functional theory (DFT) and its timedependent DFT (TD-DFT) at B3LYP with TZVP basis set. The calculated absorption and emission spectra are used to describe the photophysical properties. The absorption spectra of HBQ derivatives are blue shifted compared with that of HBQ while their emission spectra are blue-shifted except those of IPRO and PRP compounds are red shifted. The IR spectra of all compounds indicated that the O−H bond are strengthened in excited state (S1) state. The potential energy curves (PECs) of proton transfer (PT) coordinate of all compounds were scanned by fixing O‒H bond length. The results show that the PT process in the ground state is not likely to occur, but it is possible in S1 state with less required PT barrier. On-the-fly dynamics simulations in the S1 state were employed to g determine reaction mechanisms and the time evolution of the ESIPT reaction. The ESIPT times in all compounds take place in ultrafast time scale (within 100 fs). Once the PT is complete, the internal conversion is initiated by twisted skeleton. The structural changes alter the electronic spectra but do not significantly affect ESIPT of HBQ derivatives.

Chiang Mai University Library

Address: Chiang Mai

Email: cmulibref@cmu.ac.th

Name: Supawadee Namuangruk

Role: Chairman

Name: Nawee Kungwan

Role: Member

Name: Chanisorn Ngaojampa

Role: Member

Created: 2017

Modified: 2020-01-05

Issued: 2020-01-05

วิทยานิพนธ์/Thesis

application/pdf

CallNumber: Th 547.869 W277T

eng

DegreeName: Master of Science

Level: Master's Degree

Descipline: Chemistry

Grantor: Chiang Mai University

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