(2,2′-Bi­pyridine)­chlorido­[diethyl (2,2′:6′,2′′-terpyridin-4-yl)phospho­nate]ruthenium(II) hexa­fluorido­phosphate aceto­nitrile/water solvate

The cationic complex in the title compound, [RuCl(C(10)H(8)N(2))(C(19)H(20)N(3)O(3)P)]PF(6)·0.83CH(3)CN·0.17H(2)O, is a water-oxidation precatalyst functionalized for TiO(2) attachment via terpyridine phospho­nate. The The Ru(II) atom in the complex has a distorted octa­hedral geometry due to the restricted bite angle [159.50 (18)°] of the terpyridyl ligand. The dihedral angle between the least-squares planes of the terpyridyl and bipyridyl moieties is 86.04 (14)°. The mean Ru—N bond length for bi­pyridine is 2.064 (5) Å, with the bond opposite to Ru—Cl being 0.068 Å shorter. For the substituted terpyridine, the mean Ru—N distance involving the outer N atoms trans to each other is 2.057 (6) Å, whereas the bond length involving the central N atom is 1.944 (5) Å. The Ru—Cl distance is 2.4073 (15) Å. The P atom of the phospho­nate group lies in the same plane as its adjacent pyridyl ring, with the ordinary character of the bond between P and C(tpy) [1.801 (6) Å] allowing for free rotation of the terpyridine substituent around the P—C(tpy) axis. The aceto­nitrile solvent mol­ecule was refined to be disordered with two water mol­ecules; occupancies for the acetontrile and water mol­ecules were 0.831 (9) and 0.169 (9), respectively. Also disordered was the PF(6) (−) counter-ion (over three positions) and one of the eth­oxy substituents (with two positions). The crystal structure shows significant intra- and inter­molecular H⋯X contacts, especially some involving the Cl(−) ligand.