Tetra(3‐methoxypropionato)diruthenium(II,III) Units: Supramolecular Organization in the Complex [Ru2(μ‐O2CCH2CH2OMe)4(H2O)2]BF4

The synthesis and characterization of Ru₂Cl(μ‐O₂CCH₂CH₂OMe)₄ ( 1 ), [Ru₂(μ‐O₂CCH₂CH₂OMe)₄(H₂O)₂]BF₄ ( 2 ), PPh₄[Ru₂Cl₂(μ‐O₂CCH₂CH₂OMe)₄] ( 3 ), (PPh₄)₂[Ru₂Br₂(μ‐O₂CCH₂CH₂OMe)₄]NO₃ ( 4 ), and (PPh₄)₂[Ru₂I₂(μ‐O₂CCH₂CH₂OMe)₄]I_0.5(NO₃)_0.5 ( 5 ), are described. The structure of complexes 2 – 5 was established by single crystal X‐ray diffraction. All complexes show a diruthenium(II, III) unit bridged by four 3‐methoxypropionate ligands. The cationic complex 2 have two axially coordinated water molecules, with a Ru–Ru bond distance of 2.2681(12) Å. This complex shows a supramolecular two‐dimensional organization across hydrogen bonded between the axial water molecules and two methoxy groups of adjacent diruthenium units. The metal‐metal bond lengths, in the anionic complexes 3 , 4 , and 5 , are 2.3039(5), 2.3077(6), and 2.3115(8) Å, respectively. These distances are longer than the observed in compound 2 . In the anionic complexes, the axial positions of the diruthenium units are occupied by two halide ligands. Complexes 3 – 5 have PPh₄⁺ cations as counterion, although 4 and 5 are double salts with PPh₄NO₃ and PPh₄I_0.5(NO₃)_0.5, respectively. All compounds have been also characterized by elemental analysis, magnetic measurements, and spectroscopic techniques.