?-2,3,5,6-Tetra-kis(pyridin-2-yl)pyrazine-bis-[(2,2':6',2''-terpyridine)-ruthenium(II)] tetra-kis-(hexa-fluoridophosphate) acetonitrile tetra-solvate.

ABSTRACT: In the title compound [Ru(2)(C(15)H(11)N(3))(2)(C(24)H(16)N(6))](PF(6))(4)·4CH(3)CN, two of the counter-ions and one of the solvent mol-ecules are disordered with occupancies for the major components between 0.57?(2) and 0.64?(1). The structure of the dinuclear tetracation exhibits significant distortion from planarity in the bridging 2,3,5,6-tetra-kis-(pyridin-2-yl)pyrazine (tppz) ligand, which has a saddle-like geometry with an average dihedral angle of 42.96?(18)° between adjacent pyridine rings. The metal-ligand coordination environment is nearly equivalent for the two Ru(II) atoms, which have a distorted octa-hedral geometry due to the restricted bite angle [157.57?(13)-159.28?(12)°] of their two mer-arranged tridendate ligands [2,2':6',2''-terpyridine (tpy) and tppz] orthogonal to each other. At the peripheral tpy ligands, the average Ru-N bond distance is 2.072?(4)?Å for the outer N atoms trans to each other (N(outer)) and 1.984?(1)?Å for the central N atoms (N(central)). At the bridging tppz ligand, the average metal-ligand distances are significantly shorter [2.058?(4)?Å for Ru-N(outer) and 1.965?(1)?Å for Ru-N(central)] as a result of both the geometric constraints and the stronger ?-acceptor ability of the pyrazine-centered bridge. The dihedral angle between the two tpy planes is 27.11?(6)°. The intra-molecular linear distance between the two Ru atoms is 6.6102?(7)?Å.

SUBMITTER: Jude H 

PROVIDER: S-EPMC3569182 | biostudies-literature | 2013 Feb

REPOSITORIES: biostudies-literature