Three novel thiophene substituted bipyridine ligands and their corresponding rhenium complexes were synthesized and tested for the electrocatalytic reduction of CO2. Two complexes underwent oxidative electropolymerization on a glassy carbon electrode (GCE) surface. The conductive polymers chemically deposited on the GCE allow electron transport from the surface to the polymer-attached rhenium catalytic center in contact with the solution. The chemically modified electrodes show significant catalytic activities for CO2 reduction, and moderate relative higher stabilities when compared with the homogeneous solution counterparts.

BACKGROUND\ud In spite of its efficiency and versatility, examples of the use of N-hydroxyphthalimide (NHPI) as catalyst for oxidations at industrial scale are scant, mainly due to the lack of methodologies for the recovery and reuse of the catalyst. This paper reports a step by step investigation of the aerobic oxidation of cumene (CU), in order to verify the usability of NHPI catalysis in industrial processes.\ud \ud RESULTS\ud CU is oxidized to the corresponding cumyl hydroperoxide (CHP) at 70°C in the presence of a polar co-solvent and 1% of NHPI with good conversion (>30%) and almost complete selectivity (>90%), without requiring the use of additional initiators. The catalyst is recovered at the end of the oxidation process by removal of polar co-solvent, with consequent precipitation of NHPI. The resulting filtered mixture is treated with non-basic supports, which are capable of adsorbing the residual NHPI by physical interaction. Finally, the adsorbing solids can be regenerated by washing with a polar solvent, allowing the recovery of residual catalyst.\ud \ud CONCLUSION\ud We provide evidence for the feasibility of the use of NHPI catalysis for industrial applications by investigating the case study of CU oxidation. The process can be performed under mild conditions without requiring the use of sacrificial initiators. The effect of temperature and composition in the NHPI precipitation step is investigated. The performances of basic and non-basic adsorbing beds during the recovery of residual NHPI are compared. The results obtained indicate that the recovery and recycling of the unaltered catalyst is possible without affecting, at the same time, the nature of cumyl hydroperoxide