Femtosecond Transient Absorption, Nanosecond Time-Resolved Resonance Raman, and Density Functional Theory Study of Fenofibric Acid in Acetonitrile and Isopropyl Alcohol Solvents

2011 ◽  
Vol 115 (49) ◽  
pp. 14168-14174 ◽  
Author(s):  
Ming-De Li ◽  
Wen Li ◽  
Jiani Ma ◽  
Tao Su ◽  
Mingyue Liu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Isopropyl Alcohol ◽  
Transient Absorption ◽  
Fenofibric Acid ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Time Resolved ◽  
Femtosecond Transient Absorption ◽  
Alcohol Solvents

scholarly journals A combined time-resolved infrared and density functional theory study of the lowest excited states of 9-fluorenone and 2-naphthaldehyde

2018 ◽  
Vol 512 ◽  
pp. 44-52 ◽  
Author(s):  
Magnus W.D. Hanson-Heine ◽  
James A. Calladine ◽  
Jixin Yang ◽  
Michael Towrie ◽  
Raphael Horvath ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Excited States ◽  
Density Functional ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Time Resolved

scholarly journals Photochemical α-Cleavage Reaction of 3’,5’-Dimethoxybenzoin: A Combined Time-Resolved Spectroscopy and Computational Chemistry Study

Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3548
Author(s):  
Yuanchun Li ◽  
Xiting Zhang ◽  
Zhiping Yan ◽  
Lili Du ◽  
Wenjian Tang ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Quantum Yield ◽  
Dft Calculations ◽  
Density Functional ◽  
Transient Absorption ◽  
Type I ◽  
Functional Theory ◽  
Time Resolved ◽  
Norrish Type ◽  
Intramolecular Hydrogen

Benzoin is one of the most commonly used photoinitiators to induce free radical polymerization. Here, improved benzoin properties could be accomplished by the introduction of two methoxy substituents, leading to the formation of 3’,5’-dimethoxybenzoin (DMB) which has a higher photo-cleavage quantum yield (0.54) than benzoin (0.35). To elucidate the underlying reaction mechanisms of DMB and obtain direct information of the transient species involved, femtosecond transient absorption (fs-TA) and nanosecond transient absorption (ns-TA) spectroscopic experiments in conjunction with density functional theory/time-dependent density functional theory (DFT/TD-DFT) calculations were performed. It was found that the photo-induced α-cleavage (Norrish Type I reaction) of DMB occurred from the nπ* triplet state after a rapid intersystem crossing (ISC) process (7.6 ps), leading to the generation of phenyl radicals on the picosecond time scale. Compared with Benzoin, DMB possesses two methoxy groups which are able to stabilize the alcohol radical and thus result in a stronger driving force for cleavage and a higher quantum yield of photodissociation. Two stable conformations (cis-DMB and trans-DMB) at ground state were found via DFT calculations. The influence of the intramolecular hydrogen bond on the α-cleavage of DMB was elaborated.

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