Crystal structure of a mononuclear Ru^IIcomplex with a back-to-back terpyridine ligand: [RuCl(bpy)(tpy–tpy)]⁺

Abstract

In this first crystal structure of an Ru complex with 6′,6"-bis­(pyridin-2-yl)-2,2′:4′,4":2",2"’-quaterpyridine, a ‘half’ of the ligand (one of the two terpyridyl units) is N^N^N mer-coordinated, whereas the other is free and adopts a trans,trans conformation about the inter­annular C—C bonds. The crystal packing features π–π stacking inter­actions between tpy–tpy ligands.

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

“…tppz ligand, the Ru-N bond lengths involving the outer N atoms trans to each other are 2.069 (8) and 2.070 (9) Å , whereas the Ru-N bond involving the central N atom has the much shorter length of 1.939 (7) Å as a result of both the geometric constraint imposed by such mer-arranged ligands and the stronger -acceptor ability of the pyrazine-centered bridge Jude et al, 2013). An intramolecular C13-H13Á Á ÁCl1 close contact of 2.74 Å is similar to that observed earlier for complexes containing the {RuCl(bpy)} moiety (Chen et al, 2013;Jude et al, 2008;Rein et al, 2015), although this proximity appears to be partly a consequence of geometry rather than chemically significant bonding.…”

“…The Ru atom is essentially in the equatorial mean plane formed by atoms N1, N2, N3, and N4, with a deviation of only 0.026 Å . The bidentate bpy ligand has a cis configuration, with the N4-Ru-N5 angle of 78.4 (3) , in agreement with those found in similar chlorido Ru II -bpy complexes (Chen et al, 2013;Rein et al, 2015). The N5 atom of bpy is arranged trans to the chloride ligand in a nearly linear N-Ru-Cl fashion [172.6 (2) ].…”

Catalytic Water‐Oxidation Activity of a Weakly Coupled Binuclear Ruthenium Polypyridyl Complex

“…In the complexes shown in Figure , the distortion from octahedral geometry around the metal is due to the restricted bite angle of the tridentate ligand. The calculated N1–Ru–N3 angle for the tridentate phtpy and tpy 2 ph ligands (157.6–158.3°) and the N4–Ru–N5 angle for the bidentate bpy ligand (77.4–78.2°) are very similar to those of tpy and bpy in the {Ru II (bpy)(tpy)} moieties . For phtpy and tpy 2 ph, the calculated Ru–N distance involving the N1 and N3 atoms trans to each other is 2.10–2.11 Å, whereas that involving the central N2 is much shorter (1.98–1.99 Å) as a result of the constraint by such mer ‐arranged tridentate ligands .…”