Structures and reactivities of palladium-ruthenium mixed-metal sulfido clusters derived from disulfido- or hydrosulfido-bridged diruthenium complexes

摘要

The reaction of the disulfido-bridged diruthenium complex [Cp*Ru(mu(2)-S-2)(mu(2)-SPri)(2)RuCp*] (1; CP* = eta(5)-C5Me5) with 2 equiv of [Pd(PPh3)41 in boiling toluene resulted in the formation of the palladium-ruthenium mixed-metal sulfido cluster [(Cp*Ru)(2)(mu(3)-S)(2)Pd-2(mu(2)-SPri)(SPri)-(PPh3)] (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)(mu(3)-S)(2)Pd-2-(mu(2)-SPri)Br(PPh3)] (4) and the dibromo cluster [(Cp*Ru)(2)(mu(3)-S)(2)Pd-2(mu(2)-Br)Br(PPh3)] (5). On the other hand, the cationic palladium-ruthenium sulfido cluster [(Cp*Ru)(2)(mu(3)-S)(2)Pd-2(mu(2)-Cl)(PPh3)(2)]Cl (7) was obtained by the reaction of the hydrosulfido-bridged diruthenium complex [Cp*RuCl(mu(2)-SH)(2)RuClCp*] (6) with 2 equiv of [Pd(PPh3)(4)]. The structural feature commonly observed for the 60e clusters 2, 4, 5, and 7 is the presence of a distorted-tetrahedral Pd2Ru2 core containing one Pd-Pd (2.780(l)-2.8130(8) A) and one Ru-Ru bond (2.6231-(7)-2.6386(9) Angstrom) as well as four relatively long Pd-Ru contacts (2.831(l)-3.095(2) A). Furthermore, 7 reacted with CO to afford the 64e carbonyl cluster [{Cp*Ru(CO)}(2)(mu(3)-S)(2)-{PdCl(PPh3)}(2)] (8) with a boatlike Pd2Ru2(mu(3)-S)(2) framework. The detailed structures of 2, 4, 5, 7, and 8 have been determined by X-ray crystallography. [References: 73]