Time‐resolved spectroscopic and density functional theory investigation of the photochemistry of suprofen

Abstract

The photochemistry of suprofen (SPF) was investigated by femtosecond transient absorption (fs-TA), resonance Raman (RR) and nanosecond time-resolved resonance Raman (ns-TR 3 ) spectroscopic methods to gain additional information so as to better elucidate the possible photochemical reaction mechanism of suprofen in several different solvents. In neat acetonitrile (MeCN), the fs-TA and ns-TR 3 experimental data indicated that the lowest lying excited singlet state S 1 (nπ*) underwent an efficient intersystem crossing process (ISC) to the excited triplet state T 3 (ππ*), followed by an internal conversion (IC) process to T 1 (ππ*). In the aqueous solution, a triplet biradical species ( 3 ETK-1) was obtained as the product of a decarboxylation process from triplet suprofen anion ( 3 SPF À ) and the reaction rate of the decarboxylation process was determined by the concentration of H 2 O. A protonation process for 3 ETK-1 leads to formation of a neutral species ( 3 ETK-3) that was directly observed by ns-TR 3 spectra, then this 3 ETK-3 species decayed via ISC process to generate final product.

Excited state dynamics of some nonsteroidal anti-inflammatory drugs: A surface-hopping investigation

“…An experimental time-resolved absorption study of excited state dynamics of SUP in acetonitrile by Du et al is available in the literature [8]. They obtain a decrease of the S 1 signal simultaneous to the increase of the T 1 signal, which is only in qualitative agreement with our results, as their time constants for the singlet decay is about five times larger than ours (2.3 versus 0.45 ps, respectively).…”

“…The experimental absorption spectrum of SUP in acetonitrile [8] (where the molecule is mainly present in its neutral form) shows two peaks at 264 nm (4.63 eV) and 289 nm (4.29 eV), which are red shifted upon deprotonation [8,37]. Comparing these data with the calculated S 0 → S 1 and S 0 → S 2 vertical transition energies of Table 2, the S 1 and S 2 states appear to be too close in energy, in between the experimental peaks, still not far from them.…”

“…The investigation of the photophysics of drugs or the photoreactive paths that might be activated upon photon absorption is crucial for identifying photoinitiated side effects, as well as in the design of novel and improved drugs. In the literature, there are a few experimental and computational studies on the photophysics of NSAIDs, most often based on steady state results [3,4,5,6,7,8,9,10,11,12,13,14], or on quantum chemical calculations on the energetics of their excited states, mainly at DFT/TD-DFT level of theory [2,15,16,17,18]. However, investigations of the excited state dynamics of these molecules are still lacking.…”

Multilayer core–shell MoS2/CdS nanorods with very high photocatalytic activity for hydrogen production under visible-light excitation and investigation of the photocatalytic mechanism by femtosecond transient absorption spectroscopy

“…The fs-TA experiments were done employing an experimental setup and methods detailed previously 26,27 and only a brief description is provided here. A regenerative amplied Ti:sapphire laser system with an automated data acquisition system were used to conduct the femtosecond transient absorption (fs-TA) spectroscopy experiments, in which the amplier was seeded with the 120 fs laser pulses from an oscillator laser system.…”

Recent advances in linear and non‐linear Raman spectroscopy. Part X

“…[85] Time-resolved and ultrafast Raman spectroscopy Du and co-workers carried out a time-resolved spectroscopic and density functional theory investigation of the photochemistry of suprofen to gain additional information to better elucidate the possible photochemical reaction mechanisms of suprofen in several different solvents. [86] Resonance Raman spectroscopy…”