Intramolecular Oxidative Addition Triggered by One-Electron Oxidation of Molybdenum(iii) Tris(anilide): Generation of Molybdenum(v) Imido Aryl Bis(anilide) by Autocatalysis
Albert Paparo*, Tobias Schindler, Jan van Leusen, Jessica Cook, Thomas P. Spaniol, Paul Kögerler, Manuel Temprado*, Christopher C. Cummins* and Jun Okuda*,
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引用次数: 0
Abstract
One-electron oxidation of molybdenum(iii) tris(anilide) Mo(N[tBu]Ar)3 (Ar: ArMe = 3,5-Me2C6H3 and ArPh = 3,5-Ph2C6H3) led to intramolecular oxidative addition across the N–Cipso bond of a ligated anilide to form the cationic Mo(vi) imido/aryl bis(anilide) complexes [Mo(N[tBu]Ar)2(═NtBu)(Ar)][B(C6F5)4]. One-electron reduction of [Mo(N[tBu]ArMe)2(═NtBu)(ArMe)][B(C6F5)4] allowed access to the neutral Mo(v) species [Mo(N[tBu]ArMe)2(═NtBu)(ArMe)]. The d1 electron configuration was confirmed through EPR spectroscopy and the Evans method. Compound [Mo(N[tBu]ArMe)2(═NtBu)(ArMe)] was experimentally and theoretically shown to be stable against reductive elimination which would form the energetically less favorable Mo(N[tBu]Ar)3. The high activation barrier has so far prevented Mo(N[tBu]Ar)3 from isomerizing spontaneously to [Mo(N[tBu]ArMe)2(═NtBu)(ArMe)]. An autocatalytic process was developed to access [Mo(N[tBu]ArMe)2(═NtBu)(ArMe)] through reduction of [Mo(N[tBu]ArMe)2(═NtBu)(ArMe)][B(C6F5)4] by Mo(N[tBu]Ar)3, which itself was converted into the oxidizing agent. Attempts to access stable Mo(iv) cations with 4,4′-bipyridine only resulted in labile binding of 4,4′-bipyridine to one or two molybdenum(iii) tris(anilide) complexes.
期刊介绍:
Organometallics is the flagship journal of organometallic chemistry and records progress in one of the most active fields of science, bridging organic and inorganic chemistry. The journal publishes Articles, Communications, Reviews, and Tutorials (instructional overviews) that depict research on the synthesis, structure, bonding, chemical reactivity, and reaction mechanisms for a variety of applications, including catalyst design and catalytic processes; main-group, transition-metal, and lanthanide and actinide metal chemistry; synthetic aspects of polymer science and materials science; and bioorganometallic chemistry.