Ruthenium complexes containing bridging dppm and benzene-1, 2-dithiolato ligands: X-ray crystal structure of [Ru₂(CO)₄ {μ-S(C₆H₄)S} (μ-dppm)]

Abstract

The reaction of benzene-1,2-dithiol with [Ru₃(CO)₁₀(μ-dppm)] <b>1</b> in refluxing THF afforded two new compounds [Ru₂(CO)₄ {μ-S(C₆H₄)S}(μ-dppm)] <b>2</b> and [Ru₃(CO₈{μ-S(C₆H₄)S}(μ-dppm)] <b>3</b> which were characterized by elemental analysis, infrared, ¹H and ³¹P{¹H} NMR and mass spectra. The structure of <b>2</b> was determined by single crystal X-ray diffraction analysis. The compound crystallizes in the monoclinic space group <i>P</i>2₁/n, with <i>a= </i>1 0.3133(2), <i>b= </i>16.9806(3), <i>c= </i>19.5605(3) Å, α=90, β=100.2298(11), γ=90°, <i>V</i>=3371.10(10) ų and Z=4. Both Ru atoms are in distorted octahedral geometry. For each ruthenium, two CO groups in <i>cis </i>positions, one bridged S atom and the other bonded Ru atom occupy the equatorial sites, and the other bridged S atom and a P atom of the bridging dppm ligand are in <i>trans</i> positions on the meridional axis. Of the two S atoms, one lies in the Ru₂P₂ plane while the other is perpendicular to this plane, thus making them nonequivalent but keeping the two P atoms of the bridging dppm ligand identical. The 50-electron compound <b>3</b> contains a doubly briddging dithiolato and a bridging dppm ligand. Protonation of <b>2</b> with trifluroacetic acid results in the formation of the cationic hydrido species [(μ-H)Ru₂(CO)₄ {μ-S(C₆H₄)S} (μ-dppm)]⁺ which has been characterized by spectroscopic data.