A time-resolved spectroscopy and density functional theory study of the solvent dependent photochemistry of fenofibric acid.
Title | A time-resolved spectroscopy and density functional theory study of the solvent dependent photochemistry of fenofibric acid. |
Publication Type | Journal Article |
Year of Publication | 2013 |
Authors | Li, Ming-De, Ma Jiani, Su Tao, Liu Mingyue, and Phillips David Lee |
Journal | Physical chemistry chemical physics : PCCP |
Volume | 15 |
Issue | 5 |
Pagination | 1557-68 |
Date Published | 2013 Feb 7 |
ISSN | 1463-9084 |
Keywords | Absorption, Acetonitriles, Fenofibrate, Solvents, Spectrum Analysis, Raman, Time Factors, Water |
Abstract | The solvent dependent photochemistry of fenofibric acid (FA) was studied by femtosecond transient absorption and nanosecond time-resolved resonance Raman experiments and density functional theory calculations. In acetonitrile-rich solution, a typical nπ* triplet state FA ((3)FA) is formed through a highly efficient intersystem crossing and then the (3)FA species undergoes some reaction with water to generate a ketyl radical intermediate at low water concentrations. In contrast, nπ* (3)FA changes from a reaction with water to generate a ketyl radical intermediate at lower water concentrations to a decarboxylation reaction with the assistance of water molecules to produce a biradical intermediate at higher water concentrations in water-rich solutions. The decarboxylation reaction leads to the formation of the FA carbanion in 50% phosphate buffer solution and the FA carbanion is observed on the picosecond to nanosecond time scale and the cleavage of the FA carbanion gives rise to the enolate 3(-) anion at later nanosecond delay times. As regards fenofibrate (FB), it only exhibits a benzophenone-like photochemistry, which consists of some reaction with water to generate a ketyl radical intermediate, being observed in the different aqueous solutions. |
DOI | 10.1039/c2cp41739a |
Alternate Journal | Phys Chem Chem Phys |