A Designed TEMPO‐derivate Catalyst with Switchable Signals of EPR and Photoluminescence: Application in the Mechanism of Alcohol Oxidation. Issue 16 (28th June 2018) - Yin, Lu
Abstract: Construction the in situ, real‐time monitoring methodology for chemical changes, especially in the mechanism of oxidation, has long been regarded as a significant and challenging concern. Herein, we designed and synthesized a TEMPO‐mediated alkynylplatinum(II) terpyridine complex with switchable activity in photoluminescence and EPR (Electron Paramagnetic Resonance) spectra. This complex of alkynylplatinum(II) terpyridine‐TEMPO [(2, 2, 6, 6‐tetramethylpiperidin‐1‐yl)oxyl] is paramagnetic, while the in situ formed alkynylplatinum(II) terpyridine‐TEMPOH is diamagnetic, so that concentration changes of TEMPO/ TEMPOH species were obtained successfully by photoluminescence and EPR spectra in an operando way. As a model example, we investigated the mechanism of alcohol oxidation mediated by TEMPO/ bis(acetoxy)iodo]benzene (BAIB). It was found that, with the consumption of co‐oxidant (BAIB), the concentration and conformation of catalyst (TEMPO) were changed gradually, and the vital role of catalyst and co‐oxidant in the benzyl alcohol oxidation was clearly showed by photoluminescence and EPR spectroscopies. On the basis of these observations, we suggested an effective methodology to study the mechanism of chemical reaction, which is promising for further practical applications in analytical or environmental issues. Abstract : Marching to a platinum TEMPO : A TEMPO‐mediated platinum terpyridine complex was designed and synthesized. This complex showed switchable signals of EPR and photoluminescence in situ states, which can serve as catalyst and bifunctional probe during the reaction. Hereby, a method combined EPR and fluorescence spectra was established and applied successfully to study the mechanism of alcohol oxidation.