Dinuclear ruthenium(II) carbonyl complexes bridged by a C(O)CH2C5H3NCH2 group:: synthesis, characterization and crystal structures

The reaction of [Ru-3(CO)(12)] with 2,6-bis(chloromethyl)pyridine (ClCH2C5H3NCH2Cl) gave the scarcely soluble complex 1, [Ru2Cl2{C(O)CH2C5H3NCH2}(CO)(4)]. Further reactions of 1 with MeOH and PPh3 under appropriate conditions afforded organic-soluble complexes [Ru-2(mu-Cl){mu-C(O)CH2C5H3NCH2-C,N,C'}Cl(CO)(4)(MeOH)(2)] 2 and [Ru-2(mu-Cl){mu-C(O)CH2C5H3NCH2-C,N,C'}Cl(CO)(n)(PPh3)(m)] (n = 4, m = 13; n = 3, m = 24), respectively. Complexes 2-4 were characterized by H-1, C-13 and P-31 (for 3 and 4) NMR spectroscopy and by single-crystal structure determinations. These complexes are dinuclear and two Ru atoms are doubly connected by a chlorine atom and a C(O)CH2C5H3NCH2 group. Each of the metal atoms in 2 has a distorted octahedral co-ordination, while in 3 and 4 one metal atom adopts a distorted octahedral geometry and the other pseudo-octahedral; the latter geometry is completed by a Ru ... Cl secondary bonding interaction [2.055(2) in 3; 2.941(2) Angstrom in 4].