| Abstract |
The new copper(II) complexes [Cu(mu-1 kappa O:2 kappa ONN -HL1)(mu-1 kappa O:2 kappa O -NO3)](2)center dot[Cu(mu-1 kappa O:2 kappa ONN -HL1)(CH3OH)](2)(NO3)(2) (1) and [Cu(kappa ONN -HL2)(mu-1 kappa OO :2 kappa O -NO3)](n) (2), derived from the new pro-ligands H(2)L1 = 2-(5,6-dihydroindolo[1,2-c]quinazolin-6-yl)-5-methylphenol and H(2)L2 = 2-(5,6-dihydroindolo[1,2-c]quinazolin-6-yl)-4-nitrophenol, were synthesized and characterized by elemental analysis, FT-IR, ESI-MS, and their structural features were unveiled by single-crystal X-ray diffraction analysis. This discloses a dimeric structure for 1 and a polymeric infinite 1D metal-organic chain for 2. The complexes were evaluated as catalysts for the oxidation of toluene, a volatile organic compound (VOC), and for oxygen reduction and water splitting reactions. 1 exhibits a higher activity for the peroxidative conversion of toluene to oxygenated products (total yields up to 38\%), whereas 2 demonstrates a superior performance for electrochemical energy conversion applications, i.e., for oxygen reduction (ORR), oxygen evolution (OER) and hydrogen evolution (HER) reactions in an alkaline medium in terms of higher ORR current densities, lower Tafel slope (73 mV dec(-1)) and higher number of electrons exchanged (3.9), comparable to that of commercial Pt/C. Complex 2 also shows a better performance with lower onset potential and higher current densities for both OER and HER when studied as electrocatalyst for water splitting. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. |
