Photoelectrochemical reaction mechanisms The reduction of benzophenone and 4-halobenzophenones

Channel Electrodes — A Review

“…Again kinetic and mechanistic information is given. Other examples include the photodehalogenation of halo-anthraquinones [37,46], where ESR has detected the spectra of the radical anions of the dehalogenated species. The reaction scheme for the reduction of bromoanthraquinone is given in Scheme 3 below where H-S is the solvent/supporting electrolyte system.…”

“…It is hoped that this scheme can be extended to facilitate the dechlorination of polychloro-biphenyls (PCBs) which can be environmental hazard [46,127,128].…”

“…Thus channel cells for electrochemical studies in conjunction with IR, UV/visible, ESR and fluorescence spectroscopy have all been employed [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37]. Fourth, the possibility of irradiating the electrode surface through the solution permits photoelectrochemical studies to be readily undertaken in the channel electrode geometry [2,[38][39][40][41][42][43][44][45][46]. Fifth, the possibility of double electrode experiments is readily implemented [47][48][49][50][51][52][53][54][55][56][57][58][59][60][61] Last, this latter type of experiment may be generalized so that an electrochemical detector is located downstream of an insulating solid, so as to study reactions of nonconducting solid/liquid interfaces …”

A Microfluidic Channel Flow Cell for Electrochemical ESR

“…It is well-established that the measurement of voltammetry under conditions of hydrodynamic flow can greatly simplify electrochemical problems, by allowing the dominant mode of mass transport to be carefully controlled and hence the experimental time scale varied. , In particular, the channel electrode has received a wealth of attention, which has demonstrated that the consideration of mathematically well-defined convection may permit rigorous treatment of mechanistic features of electrode reactions and facilitate the extraction of a range of kinetic information from experimental data. − A notable application of the channel electrode is in electron spin resonance spectroscopy (ESR); this spectroelectochemical methodology has been demonstrated to provide significant insights into the identity and reactivity of paramagnetic species . In channel flow cell applications the device is held within the resonant cavity of an ESR spectrometer, and paramagnetic species generated at the electrode surface can be simultaneously characterized and quantified according to the structure and intensity of the ESR spectrum observed. − , By modeling the concentration profile of the electrogenerated radical species downstream of the electrode, the ESR signal intensity and its variation with solution flow rate can be predicted for stable and reactive species, and in the latter case, kinetic parameters for homogeneous decay can be deduced…”

Photoelectrochemical dechlorination of phenols

“…The introduction of light close to an electrode has been seen to be beneficial to synthetic electrochemists, since the electrontransfer processes at the electrode may be coupled with homogeneous light-induced chemical transformations. [1][2][3][4] Specifically, it may be speculated that the dual use of electrochemical and photochemical activation of organic and organometallic molecules may lead to a wealth of hitherto unsuspected chemistry including novel mechanistic pathways, the discovery of new compounds associated with unusual reactive intermediates, and ultimately new synthetic routes. The intermediates may be produced in a controlled fashion by manipulation of the electrode potential, the nature of the electrode material, the cell design, and other reaction variables.…”