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

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journal contribution
posted on 01.06.2009, 00:00 by Chi Minh Tuong, Whitney K. Hammons, Ashley L. Howarth, Kelly E. Lutz, Ackim D. Maduvu, Laura B. Haysley, Brian R. T. Allred, Lenore K. Hoyt, Mark S. Mashuta, Mark E. Noble
The SO bridge of the complex, [Mo2(NTo)2(S2P(OEt)2)2(μ-O2CMe)(μ-SBn)(μ-SO)], 1, displayed nucleophilicity at O, giving alkylation products [Mo2(NTo)2(S2P(OEt)2)2(μ-O2CMe)(μ-SBn)(μ-SOR)]+, 4+, which contained the thioperoxide bridge. These cations were then subject to nucleophilic attack by two pathways. Debenzylation of the bridge thiolate in 4+ afforded neutral [Mo2(NTo)2(S2P(OEt)2)2(μ-O2CMe)(μ-S)(μ-SOR)], 5; de-esterification of a dithiophosphate ligand in 4+ gave [Mo2(NTo)2(S2P(O)(OEt))(S2P(OEt)2)(μ-O2CMe)(μ-SBn)(μ-SO)], 6, which contained a monoester, dithiophosphate ligand. Complex 1 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 Mo2(μ-SOR) unit to sulfenate esters (RSOR) and related derivatives.