Structures and Reactivities of Palladium−Ruthenium Mixed-Metal Sulfido Clusters Derived from Disulfido- or Hydrosulfido-Bridged Diruthenium Complexes

Abstract

The reaction of the disulfido-bridged diruthenium complex [Cp*Ru(μ 2 -S 2 )(μ 2 -SPr i ) 2 RuCp*] (1; Cp* = η 5 -C 5 Me 5 ) with 2 equiv of [Pd(PPh 3 ) 4 ] in boiling toluene resulted in the formation of the palladium-ruthenium mixed-metal sulfido cluster [(Cp*Ru) 2 (μ 3 -S) 2 Pd 2 (μ 2 -SPr i )(SPr i )-(PPh 3 )] (2). Upon treatment with benzyl bromide, stepwise substitution of the thiolato ligands in 2 by bromo ligands took place to afford the monobromo cluster [(Cp*Ru) 2 (μ 3 -S) 2 Pd 2 -(μ 2 -SPr i )Br(PPh 3 )] (4) and the dibromo cluster [(Cp*Ru) 2 (μ 3 -S) 2 Pd 2 (μ 2 -Br)Br(PPh 3 )] (5). On the other hand, the cationic palladium-ruthenium sulfido cluster [(Cp*Ru) 2 (μ 3 -S) 2 Pd 2 -(μ 2 -Cl)(PPh 3 ) 2 ]Cl (7) was obtained by the reaction of the hydrosulfido-bridged diruthenium complex [Cp*RuCl(μ 2 -SH) 2 RuClCp*] (6) with 2 equiv of [Pd(PPh 3 ) 4 ]. The structural feature commonly observed for the 60e clusters 2, 4, 5, and 7 is the presence of a distorted-tetrahedral Pd 2 Ru 2 core containing one Pd-Pd (2.780(1)-2.8130(8) A) and one Ru-Ru bond (2.6231-(7)-2.6386(9) A) as well as four relatively long Pd-Ru contacts (2.831(1)-3.095(2) A). Furthermore, 7 reacted with CO to afford the 64e carbonyl cluster [{Cp*Ru(CO)} 2 (μ 3 -S) 2 -{PdCl(PPh 3 )} 2 ] (8) with a boatlike Pd 2 Ru 2 (μ 3 -S) 2 framework. The detailed structures of 2, 4, 5, 7, and 8 have been determined by X-ray crystallography.