Dinuclear Ruthenium(II) Carbonyl Complexes Doubly Bridged by a Bromine Atom and a C₅H₃N-2-C(O)CH₂-6-CH₂ (Q) Group. Crystal Structures of Ru₂(μ-Br)(μ-Q)Br(CO)₄(PPh₃)(MeOH) and Ru₂(μ-Br)(μ-Q)Br(CO)₃(PPh₃)₂

The oxidative addition reaction of 2,6-bis(bromomethyl)pyridine to Ru₃(CO)₁₂ gave scarcely soluble {Ru₂Br₂(μ-Q)(CO)₄}_n, 1, [Q = C₅H₃N-2-C(O)CH₂-6-CH₂] or a mixture of 1 and the mononuclear complex RuBr(Q′)(CO)₃, 2, [Q′ = C₅H₃N-2-C(O)CH₂-6-CH₂Br] according to the reactant's mole ratio. Further reactions of 1 with some N- and P-donor ligands (L) afforded readily soluble dinuclear complexes, Ru₂(μ-Br)(μ-Q)Br(CO)_n(L)_m [n = 4, m = 1, L = PPh₃ 3a, or py 3b; n = 3, m = 2, L = PPh₃ 5a, or PPh₂(o-tolyl) 5b]. In this paper, the characterization of these products by the elemental analyses and the spectroscopic methods are described. The X-ray crystal structures of Ru₂(μ-Br) (μ-Q)Br(CO)₄(PPh₃)(MeOH), 4, which was obtained by crystallization of 3a from MeOH, and of 5a · (2CHCl₃) are also described. Each of the metal atoms in 4 has a distorted octahedral coordination, while in 5a · (2CHCl₃) one metal atom takes a distorted octahedral geometry and the other pseudooctahedral, which is completed by presenting a Ru ⋯ Br secondary bonding interaction.