Tethered indenyl-phosphine complexes of ruthenium(II) via reductive elimination of a ruthenium(IV) complex

Abstract

The Ru(IV) phosphine complex [(η3,η3-C 10H16)RuCl2(κ1P-LH)] (2) was synthesized from the reaction of [(η3,η3-C 10H16)RuCl2]2 with [(C 9H7)(CH2)2PPh2] (LH). Treatment of 2 with acid led to halide labilization to give [(η 3η3-C10H16)RuCl(CH 3CN)(κ1-LH)]+ [2a]+. Reductive elimination of the bis(allyl) ligand in 2 was effected in the reaction of 2, a two- or four-electron ligand (DD), Na2CO3, and KPF 6 in EtOH, resulting in the isolation of PF6 salts of monocationic tethered indenyl Ru species, [(η,κ1P-L)Ru(DD)] (3, DD = 1,5-cyclooctadiene (COD); 6, DD = 2,2′-bipyridyl (bpy)), and neutral tethered indenyl Ru complexes (4, DD = (PPh3)Cl; 5, DD = (PPh3)H). In addition to [6]PF6, [(κ1P- LH)Ru(bpy)2Cl]PF6, [7]PF6, was an additional product in the bpy reaction, as was {[(κ1P-LH)Ru(bpy)Cl] 2(μ-Cl)3}PF6, [8]-PF6, when Na2CO3 was replaced by Li2CO3. In the presence of HC1, [6]+ was found to convert to [8]+, while [8]+ was converted to [7]+ with bpy and KPF 6. The reaction of 2 with acetylacetone (acacH) gave a high yield of an unusual complex, [(η2,κ1P-LH)Ru(acac) 2] (9), in which LH adopts a rare η2, κ1P-coordination mode. The new compounds were all spectroscopically characterized, with 2, 2a, 3, 4, and 9 also determined by single-crystal X-ray diffraction analyses. © 2007 American Chemical Society.