The mononuclear ruthenium(III)-2,3,5,6-tetrakis(2-pyridyl)pyrazine complex [Ru(bpy)(tppz)Cl][PF6]2: synthesis, crystal structure, electrochemical, and spectroelectrochemical studies

Abstract

The mononuclear Ru(III) complex, [Ru(bpy)-(tppz)Cl][PF 6 ] 2 .acetylacetone, where tppz is 2,3,5,6-tetrakis(2-pyridyl)pyrazine and bpy is 2,2 0 -bipyridine, has been prepared and characterized by physicochemical and spectroscopic methods, cyclic voltammetry, and single crystal X-ray structure analysis. The coordination around the Ru(III) center is distorted octahedral, with bite angles of 80.70-161.83°for the chelating bpy and tppz ligands. The two pyridyl rings of the bpy ligand are nearly coplanar. UV-vis spectroelectrochemical studies of this complex in acetonitrile showed a reversible redox behavior evaluated by the maintenance of isosbestic points in the UV-vis spectrum for both forward reduction and reverse oxidation processes. Magnetic susceptibility data derived from paramagnetic NMR data revealed an effective magnetic moment of 1.79 BM at room temperature.

Synthesis and Characterization of New Mononuclear Ru (II) PolypyridylComplexes with Catalytic Activity

“…The Ru−Cl bond distance is 2.392(1) Å. These data agree with those reported for similar complexes [44–50] …”

“…These data agree with those reported for similar complexes. [44][45][46][47][48][49][50] Scheme 2. Molecular structure of complexes (1) to (4).…”

Nickel(II) polypyridyl Complexes of 2,4,6-Tris(2-pyridyl)-1,3,5-triazine

“…We have previously reported the crystal structures, luminescence, electrochemical, spectroelectrochemical, and magnetic properties of some polypyridyl complexes [29][30][31][32][33][34][35][36][37][38]. Many factors govern the redox, structure, luminescence, and quenching properties of polypyridyl complexes such as the type of substituents on the pyridyl rings, the oxidation states of the central metal, the thermodynamic stability of reduced or oxidized complexes in solution, the geometry, and the presence of electroactive spectator ligands.…”

Crystal structure and redox potentials of the tppz-bridged {RuCl(bpy)}+ dimer

“…A search in the Cambridge Structural Database (Groom et al, 2016) listed only four entries for the {RuCl(bpy)(tppz)} substructure. Of these, two are mononuclear complexes [one with the Ru III oxidation state (Daryanavard et al, 2009) and another at the Ru II state (Tondreau et al, 1996)] and the other two are binuclear complexes [one with tpy instead of bpy and Cl À , and another with Me 2 bpy instead of bpy and the two Cl À ligands in a cis configuration (Hartshorn et al, 1999)].…”