Alkylation of a Dimolybdenum SO Bridge, Subsequent Reactions, and Characterization of the Thioperoxide Bridge

The SO bridge of the complex, [Mo<sub>2</sub>(NTo)<sub>2</sub>(S<sub>2</sub>P(OEt)<sub>2</sub>)<sub>2</sub>(μ-O<sub>2</sub>CMe)(μ-SBn)(μ-SO)], <b>1</b>, displayed nucleophilicity at O, giving alkylation products [Mo<sub>2</sub>(NTo)<sub>2</sub>(S<sub>2</sub>P(OEt)<sub>2</sub>)<sub>2</sub>(μ-O<sub>2</sub>CMe)(μ-SBn)(μ-SOR)]<sup>+</sup>, <b>4</b><sup><b>+</b></sup>, which contained the thioperoxide bridge. These cations were then subject to nucleophilic attack by two pathways. Debenzylation of the bridge thiolate in <b>4</b><sup><b>+</b></sup> afforded neutral [Mo<sub>2</sub>(NTo)<sub>2</sub>(S<sub>2</sub>P(OEt)<sub>2</sub>)<sub>2</sub>(μ-O<sub>2</sub>CMe)(μ-S)(μ-SOR)], <b>5</b>; de-esterification of a dithiophosphate ligand in <b>4</b><sup><b>+</b></sup> gave [Mo<sub>2</sub>(NTo)<sub>2</sub>(S<sub>2</sub>P(O)(OEt))(S<sub>2</sub>P(OEt)<sub>2</sub>)(μ-O<sub>2</sub>CMe)(μ-SBn)(μ-SO)], <b>6</b>, which contained a monoester, dithiophosphate ligand. Complex <b>1</b> gave a slow and clean reaction in the crystalline state, further demonstrating its nucleophilicity by attacking a neighboring molecule in its lattice. X-ray crystallography confirmed the thioperoxide linkage and revealed structural similarities of the Mo<sub>2</sub>(μ-SOR) unit to sulfenate esters (RSOR) and related derivatives.