Homoleptic ruthenium complexes with N-heterocyclic carbene ligands as photosensitizers in the photocatalytic generation of H2 from water

Publication date: Available online 31 July 2019Source: Journal of Organometallic ChemistryAuthor(s): Javier Torres, M. Carmen Carrión, Jorge Leal, Gregorio Castañeda, Blanca R. Manzano, Félix A. JalónAbstractThere is great interest in the catalytic photoreduction of water to give hydrogen as a fuel to harness solar energy and a series of ruthenium complexes has been synthesized and tested as photosensitizers in this photoreduction process. There are very few precedents for N-heterocyclic carbene complexes in this field. The complexes obtained in this work were of the type [Ru(:CˆNˆC)2](PF6)2 and [Ru(NˆC)3](PF6)2 with N-heterocyclic carbene ligands derived from pyridine and imidazole heterocycles with methyl or benzyl substituents. The photophysical properties of the complexes were studied. Some complexes were luminescent and, although the quantum yields were rather low, the lifetimes were quite high (1.5–1.7 μs). The emissive complexes behave as photosensitizers in the generation of H2 using [Co(bpy)3]Cl2 (bpy = 2,2′-bipyridine) as catalyst and triethanolamine (TEOA) as the sacrificial reductant through an oxidative quenching mechanism. The amount of hydrogen obtained was higher for the benzyl derivative.Graphical abstractHomoleptic ruthenium complexes of the type [Ru(:CˆNˆC)2](PF6)2 and [Ru(NˆC)3](PF6)2 with N-heterocyclic ligands were synthesized and tested as photosensitizers in the photocatalytic H2 production from water with a cobalt catalyst. The lu...

Source: Journal of Organometallic Chemistry - August 1, 2019 Category: Chemistry Source Type: research