Synthesis, UV-visible spectroelectrochemistry and theoretical characterization of new polypyridyl Ru(II) complexes containing 2,4,6-tris(2-pyridyl)-1,3,5-triazine as precursors for water oxidation catalysts.

In this work, we report the syntheses and physicochemical characterization of new chloro and aqua complexes of Ru(ii) with 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz) and 2,2'-bipyridines substituted with donor and acceptor groups in the 4,4'-positions. The aqua complexes behave as precursors for water oxidation catalysts at pH = 1 using Ce(iv) as a sacrificial oxidant. Besides, the oxidized forms Ru(iv) and Ru(v) have been characterized at different pH values by electrochemistry, UV-Visible spectroscopy and spectroelectrochemistry.

Does geometry matter? Effect of the ligand position in bimetallic ruthenium polypyridine siblings.

In this work, we present the preparation of a complex [(tpy)(bpy)Ru(μ-CN)Ru(py)4(OH2)](PF6)3 (tpy = 2,2',6',2''-terpyridine; bpy = 2,2'-bipyridine; py = pyridine) that combines a ruthenium chromophore linked to another ruthenium ion that bears a labile position trans to the bridge. Substitution in this position is very attractive, as it allows us to place a quencher trans to the chromophore maximizing the separation between them. This complex allowed us to prepare a family of cyanide-bridged ruthenium polypyridines of general formula [Ru(tpy)(bpy)(μ-CN)Ru(py)4(L)]2/3+ (L = Cl-, NCS-, 4-dimethylaminopyridine or acetonitrile) and compare them with the related complexes [Ru(tpy)(bpy)(μ-CN)Ru(bpy)2(L)]2/3+ where the L ligand lies cis to the bridge.