Web Release Date: December 28,
In Pursuit of the Molybdenum(III) Tris(thiolate) Fragment: Unusual Structure of a
Dimolybdenum 
-Nitrido Complex
Department of Chemistry, Room 2-227, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307
Received May 6, 1999
Abstract:
The new molybdenum nitrido-thiolate complex N
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 NMo(OtBu)3.
In an effort to abstract the nitrido nitrogen from NMo(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
(-nitrido)dimolybdenum complex (AdS)3Mo(-N)Mo(N[tBu]Ph)3, which was isolated and characterized. An X-ray
study revealed (AdS)3Mo(-N)Mo(N[tBu]Ph)3 to possess an unsymmetrical Mo-(-N)-Mo linkage, the Mo-thiolate fragment exhibiting a substantially longer bond to the bridging nitrogen atom. The structure of (AdS)3Mo(-N)Mo(N[tBu]Ph)3 is noteworthy, displaying trigonal monopyramidal coordination at the (-N)-Mo-thiolate
Mo center. Since NMo(N[tBu]Ph)3 is a good leaving group, (AdS)3Mo(-N)Mo(N[tBu]Ph)3 should be a source
of the reactive Mo(SAd)3 fragment. In all the studied reactions of the (-nitrido)dimolybdenum complex one of
the observed products was NMo(N[tBu]Ph)3. Two products containing the Mo(SAd)3 fragment were observed:
(AdS)3MoMo(SAd)3 and [(ON)Mo(-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.
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