Novel cobalt, nickel, and iron complexes based on the pentadentate 8-hydroxyquinoline-di(2-picolyl)amine ligand were synthesized and thoroughly characterized. X-ray structures of both the cobalt and iron complexes were also obtained, showing the tendency to adopt a pseudo-octahedral geometry by coordination of an additional sixth ligand. These metal complexes were then studied as potential hydrogen-evolving catalysts (HECs) under both electrochemical and light-driven conditions. In particular, two different photochemical systems were tested involving either Ru(bpy)32+/ascorbic acid or Ir(ppy)2(bpy)+/TEA sensitizer/sacrificial donor couples. The electrochemical results showed that these metal complexes may behave as competent HECs. However, under photochemical conditions, only the cobalt compound displayed substantial hydrogen-evolving activity in both ruthenium- and iridium-based systems. The nickel and iron complexes, on the other hand, exhibited appreciable photocatalytic activity only in the iridium-based photochemical system, while showing negligible hydrogen evolution ability when employed in the ruthenium-based one.

Cobalt, nickel, and iron complexes of 8-hydroxyquinoline-di(2-picolyl)amine for light-driven hydrogen evolution

Carmo Dos Santos N. A.;Badetti E.;Licini G.;Zonta C.
2017

Abstract

Novel cobalt, nickel, and iron complexes based on the pentadentate 8-hydroxyquinoline-di(2-picolyl)amine ligand were synthesized and thoroughly characterized. X-ray structures of both the cobalt and iron complexes were also obtained, showing the tendency to adopt a pseudo-octahedral geometry by coordination of an additional sixth ligand. These metal complexes were then studied as potential hydrogen-evolving catalysts (HECs) under both electrochemical and light-driven conditions. In particular, two different photochemical systems were tested involving either Ru(bpy)32+/ascorbic acid or Ir(ppy)2(bpy)+/TEA sensitizer/sacrificial donor couples. The electrochemical results showed that these metal complexes may behave as competent HECs. However, under photochemical conditions, only the cobalt compound displayed substantial hydrogen-evolving activity in both ruthenium- and iridium-based systems. The nickel and iron complexes, on the other hand, exhibited appreciable photocatalytic activity only in the iridium-based photochemical system, while showing negligible hydrogen evolution ability when employed in the ruthenium-based one.
2017
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/3335630
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