engleski

Formation of Quinone Methides by Ultrafast Photodeamination: A Spectroscopic and Computational Study

Formation of quinone methides (QMs) by photoelimination of an ammonium salt from cresol derivatives was investigated by femtosecond transient absorption spectroscopy (fs-TA) and computationally by TD-DFT using the PCM(water)/(TD-)B3LYP/6-311++G(d, p) level of theory. The photoelimination takes place in an adiabatic ultrafast reaction on the S1 potential energy surface delivering the corresponding QMs(S1), which were detected by fs-TA. Computations predicted a high energy cation intermediate in the pathway between the Franck-Condon state of a monoammonium salt and the corresponding QM(S1) that was not detected by fs-TA. On the other hand, elimination from a disalt in H2O takes place in one step, giving directly the QM(S1). The combined experimental and theoretical investigation fully disclosed the formation of QMs by the deamination reaction mechanism, which is important in the application of cresols or similar molecules in biological systems.

photodeamination ; quinone methide ; DFT computations ; ultrafast spectroscopy

nije evidentirano