Femtosecond dynamics of a non-steroidal anti-inflammatory drug (piroxicam) in solution: The involvement of twisting motion
- 作者：Michał ; Gil ; Abderrazzak Douhal
- 关键词：Non-steroidal anti-inflammatory drug ; Piroxicam ; Femtosecond ; Ultrafast dynamics ; Proton transfer ; Twisting motion ; Viscosity ; Transient absorption ; Stimulated emission ; Potential-energy surfaces
- 刊名：Chemical Physics
- 出版年：2008
- 期刊代码：18_03010104
- 类别：ch
- 出版时间：23 June 2008
- 卷：350
- 期：1-3
- 页码：179-185
- 文件大小：1032 K
摘要
In this contribution, we report on fast and ultrafast dynamics of a non-steroidal anti-inflammatory drug, piroxicam (PX), in methyl acetate (MAC) and triacetin (TAC), two solvents of different viscosities. The enol form of PX undergoes a femtosecond (shorter than 100 fs) electronically excited state intramolecular proton-transfer reaction to produce keto tautomers. These structures exhibit an internal twisting motion to generate keto rotamers in 
es/223c.gif" alt="not, vert, similar" title="not, vert, similar" border="0">2–5 ps, a time being longer in TAC. The transient absorption/emission spectrum is very broad indicating that the potential-energy surface at the electronically excited state is very flat, and reflecting the involvement of several coordinates along which the wavepacket of the fs-produced structures evolve.