Reactivity of [CpMo(CO)2]2 towards heterocyclic thiols: Synthesis, structure, and bonding in the sulfido-ligated cluster Cp3Mo3(μ-CO)2(μ-κ2-C7H4NS)(μ-S)(μ3-S)

•Reactions between [CpMo(CO)2]2 and heterocyclic thiols.•Synthesis of sulfido-ligated trimolybdenum clusters.•Bonding in Cp3Mo3(μ-CO)2(μ-κ2-C7H4NS)(μ-S)(μ3-S).•C–H and C–S bond cleavage of heterocyclic thiols.

The electronically unsaturated dimolybdenum complex [CpMo(CO)2]2 (1) reacts with the π-excessive heterocycle 2-mercapto-1-methylimidazole at 110 °C to afford the mononuclear molybdenum complex CpMo(CO)2(κ2-C4H5N2S) (2) and the trimolybdenum cluster Cp3Mo3(μ-CO)2(μ-κ2-C4H5N2)(μ-S)(μ3-S) (3) in 22% and 20% yields, respectively. A similar reaction between 1 and the benzoannulated heterocycle 2-mercaptobenzothiazole furnishes CpMo(CO)2(κ2-C7H4NS2) (4) and Cp3Mo3(μ-CO)2(μ-κ2-C7H4NS)(μ-S)(μ3-S) (5) in 17% and 20% yields, respectively. Compounds 2 and 4 consist of a single molybdenum atom with two carbonyl groups, a cyclopentadienyl ligand, and a chelating heterocyclic thiolato ligand. The trimolybdenum clusters 3 and 5 consist of three cyclopentadienyl ligands, a metalated heterocyclic ligand, edge-bridging and face-capping sulfido ligands, and a pair of semi-bridging carbonyl ligands. All new compounds have been fully characterized in solution by IR and NMR spectroscopy, and the solid-state structures of 3 and 4 have been determined by single-crystal X-ray diffraction analyses. The bonding in cluster 3 has been computationally investigated by Density Functional Theory (DFT), and the data support a cluster that is electronically saturated with 48e and where both sulfido ligands function as 4e donor groups.

Graphical abstractSynthesis, structure, and bonding in new sulfido-ligated trimolybdenum clusters are described.Figure optionsDownload full-size imageDownload as PowerPoint slide