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In Pursuit of the Molybdenum(III) Tris(thiolate) Fragment: Unusual Structure of a Dimolybdenum μ-Nitrido Complex

1999; American Chemical Society; Volume: 39; Issue: 2 Linguagem: Inglês

10.1021/ic9904891

1520-510X

Theodor Agapie, Aaron L. Odom, Christopher C. Cummins,

Asymmetric Hydrogenation and Catalysis

The new molybdenum nitrido-thiolate complex N triple bond Mo(SAd)3 (Ad = 1-adamantyl) was prepared by a ligand exchange route involving reaction of Ti(SAd)(OiPr)3 with Chisholm's nitrido-butoxide complex N triple bond Mo(OtBu)3. In an effort to abstract the nitrido nitrogen from N triple bond Mo(SAd)3, the compound was treated with Mo(N[tBu]Ph)3, a three-coordinate molybdenum(III) complex. This resulted in formation of the unusual and thermally unstable (mu-nitrido)dimolybdenum complex (AdS)3Mo(mu-N)Mo(N[tBu]Ph)3, which was isolated and characterized. An X-ray study revealed (AdS)3Mo(mu-N)Mo(N[tBu]Ph)3 to possess an unsymmetrical Mo-(mu-N)-Mo linkage, the Mo-thiolate fragment exhibiting a substantially longer bond to the bridging nitrogen atom. The structure of (AdS)3Mo-(mu-N)Mo(N[tBu]Ph)3 is noteworthy, displaying trigonal monopyramidal coordination at the (mu-N)-Mo-thiolate Mo center. Since N triple bond Mo(N[tBu]Ph)3 is a good leaving group, (AdS)3Mo(mu-N)Mo(N[tBu]Ph)3 should be a source of the reactive Mo(SAd)3 fragment. In all the studied reactions of the (mu-nitrido)dimolybdenum complex one of the observed products was N triple bond Mo(N[tBu]Ph)3. Two products containing the Mo(SAd)3 fragment were observed: (AdS)3Mo triple bond Mo(SAd)3 and [(ON)Mo(mu-SAd)(SAd)2]2. Upon treatment with pyridine, the tris(thio-1-adamantyl)-(nitrosyl)molybdenum dimer forms the pyridine adduct (AdS)3Mo(NO)(py), which is a monomer.