Electron-Deficient Early−Late Heterobimetallic Sulfido Clusters. Unusual Reactivities of Ti₂Ru₂S₄ Cubane-Type Clusters with Four Cyclopentadienyl Coligands

Abstract

Treatment of [Cp2Ti(SH)2] (1; Cp = η5-C5H5) with [(Cp*Ru)4(μ3-Cl)4] (2; Cp* = η5-C5Me5) in a Ti:Ru ratio of 1:1 afforded the hydrosulfido-bridged titanium−ruthenium heterobimetallic complex [Cp2Ti(μ2-SH)2RuClCp*] (3). Complex 3 reacted with an excess of triethylamine to give the early−late heterobimetallic cubane-type sulfido cluster [(CpTi)2(Cp*Ru)2(μ3-S)4] (4), with a loss of HCl and cyclopentadiene. An X-ray diffraction study and extended Hückel molecular orbital calculations for the 60e- cluster 4 demonstrated that 4 has four Ru→Ti dative bonds and a weak Ti−Ti interaction. The reaction of 4 with 3 equiv of [Cp2Fe][PF6] afforded the dicationic cubane-type cluster [(CpTi)2(Cp*Ru)2(μ3-S)4][PF6]2 (5), which contains an additional Ru−Ru bond. In contrast, oxidation of 4 with an excess of HCl at room temperature resulted in the formation of the neutral dichloride cluster [(CpTiCl2)(CpTi)(Cp*Ru)2(μ3-S)4] (6). Clusters 5 and 6 were converted into each other by treatment with chloride or hexafluorophosphate anion. Furthermore, substitution of one of the cyclopentadienyl ligands in 6 by a chloride anion took place in boiling 1,2-dichloroethane to give the trichloride cluster [(TiCl3)(CpTi)(Cp*Ru)2(μ3-S)4] (7). The detailed structures of these oxidized cubane-type clusters 5·2DMF, 6·CH2Cl2, and 7·CH2Cl2 as well as the hydrosulfido-bridged dinuclear complex 3 have also been determined by X-ray crystallography. The Ti2Ru2S4 cubane-type cores in 5−7 differ considerably in structure from each other, depending upon the ancillary ligands bound to the Ti atoms, although they have a Ru−Ru bond and two Ru→Ti dative bonds in common.

Cubane-Type Heterometallic Sulfido Clusters: Incorporation of Two Metal Fragments into a Dinuclear ReS(μ-S)2ReS Core Affording Bimetallic M2Re2(μ3-S)4Clusters (M = Ru, Pt, Cu) or Trimetallic MM‘Re2(μ3-S)4Clusters via Incomplete Cubane-Type MRe2(μ3-S)(μ2-S)3Intermediates (M = Ru, Rh, Ir; M‘ = Mo, W, Pd, Ru, Rh)

“…Our recent studies toward this direction have revealed that hydrosulfido-bridged dinuclear complexes such as [Cp*MCl(μ-SH) 2 MCp*Cl] (M = Ru, Rh, Ir; Cp* = η 5 -C 5 Me 5 ) and [Cp 2 Ti(μ-SH) 2 RuCp*Cl] (Cp = η 5 -C 5 H 5 ) serve as versatile precursors for preparing the homo- and heterobimetallic cubane-type clusters such as [(Cp*M) 4 (μ 3 -S) 4 ] (M = Ru, Rh, Ir), [(CpTi) 2 (Cp*Ru) 2 (μ 3 -S) 4 ], and [CpTi(Cp*Ru) 3 (μ 3 -S) 4 ] through a dehydrochlorination−dimerization process (Scheme ). In addition, it has also been found that the Ir−Mo cluster [(Cp*Ir) 2 {Mo(O)Cl 2 }{MoCl 2 (DMF)}(μ 3 -S) 4 ] can be obtained from [Cp*IrCl(μ-SH) 2 IrCp*Cl] and [MoO(DMF) 3 (μ-S) 2 MoO(DMF) 3 ] 2+ through condensation and concomitant dehydration, which is also shown in Scheme .…”

Synthesis of Bimetallic Cubane-Type Mo2M2S4 Clusters (M = Ir, Rh, Ru) and Reductive Cleavage of the N−N Bond of 1,1-Methylphenylhydrazine Affording N-Methylaniline Using Mo2Ir2S4 and Mo2Rh2S4 Clusters as Catalyst Precursors

“…In previous papers we have reported that dinuclear complexes containing both bridging and terminal sulfido ligands, [{M(S)(S 2 CNEt 2 )} 2 (μ 2 -S) 2 ] (M = Mo, W), are promising precursors to heterobimetallic clusters with M 2 M‘(μ 3 -S)(μ 2 -S) 3 and M 2 M‘ 2 (μ 3 -S) 4 cores (M‘ = Pd, Pt, Rh, Ir, Ru). The hydrosulfido-bridged dinuclear complexes [(Cp*MCl) 2 (μ 2 -SH) 2 ] (M = Rh, Ir, Ru; Cp* = η 5 -C 5 Me 5 ) and [{(η 6 - p -Pr i C 6 H 4 Me)RuCl} 2 (μ 2 -SH) 2 ] have also been shown to serve as excellent starting compounds for the synthesis of the cubane-type M 4 (μ 3 -S) 4 (M = Ir, Rh, Ru) clusters by in situ generation of the coordinatively unsaturated sulfido-bridged dinuclear species {M 2 (μ 2 -S) 2 } through the loss of HCl, followed by dimerization. − It is noteworthy that this method can be extended, for example, to the condensation of the heterobimetallic hydrosulfido-bridged complex [Cp 2 Ti(μ-SH) 2 RuCp*Cl], forming [(CpTi) 2 (Cp*Ru) 2 (μ 3 -S) 4 ] with concomitant loss of HCl and CpH, and crossed condensation between this dinuclear Ti−Ru complex and [(Cp*RuCl) 2 (μ 2 -SH) 2 ] to give [(CpTi)(Cp*Ru) 3 (μ 3 -S) 4 ] …”

New Mixed-Metal Sulfido Metal Carbonyl Complexes by Insertion of Metal Carbonyl Groups into the S−S Bond of CpMoMn(CO)5(μ-S2)

“…Mixed-metal sulfido clusters have attracted attention in the past decade, because of possible bimetallic synergistic effects 11 in certain types of heterogeneous metal sulfide catalysts. Adduct formation of hydrosulfido complexes with heterometal complexes is a practical route to mixed-metal hydrosulfido-bridged complexes. 10c, …”