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Abstract Catalysis ofO‐atom transfer (OAT) reactions is a characteristic of both natural (enzymatic) and synthetic molybdenum‐oxo and ‐peroxo complexes. These reactions can employ a variety of terminal oxidants, e. g. DMSO,N‐oxides, and peroxides, etc., but rarely molecular oxygen. Here we demonstrate the ability of a set of Schiff‐base‐MoO2complexes (cy‐salen)MoO2(cy‐salen=N,N’‐cyclohexyl‐1,2‐bis‐salicylimine) to catalyze the aerobic oxidation of PPh3. We also report the results of a DFT computational investigation of the catalytic pathway, including the identification of energetically accessible intermediates and transition states, for the aerobic oxidation of PMe3. Starting from the dioxo species, (cy‐salen)Mo(VI)O2(1), key reaction steps include: 1) associative addition of PMe3to an oxo‐O to give LMo(IV)(O)(OPMe3) (2); 2) OPMe3dissociation from2to produce mono‐oxo complex (cy‐salen)Mo(IV)O (3); 3) stepwise O2association with3via superoxo species (cy‐salen)Mo(V)(O)(η1‐O2) (4) to form the oxo‐peroxo intermediate (cy‐salen)Mo(VI)(O)(η2‐O2) (5); 4) theO‐transfer reaction of PMe3with oxo‐peroxo species5at the oxo‐group, rather than the peroxo unit leading, after OPMe3dissociation, to a monoperoxo species, (cy‐salen)Mo(IV)(η2‐O2) (7); and 5) regeneration of the dioxo complex (cy‐salen)Mo(VI)O2(1) from the monoperoxo triplet37or singlet17by a concerted, asynchronous electronic isomerization. An alternative pathway for recycling of the oxo‐peroxo species5to the dioxo‐Mo1via a bimetallic peroxo complex LMo(O)‐O−O‐Mo(O)L8is determined to be energetically viable, but is unlikely to be competitive with the primary pathway for aerobic phosphine oxidation catalyzed by1.
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This content will become publicly available on March 31, 2027
Transformation of tetranuclear [{MoO 3 (L cat )Cu} 2 ] 2− into trinuclear [MoO 2 (L cat ) 2 Cu 2 ] and possible implications for the formation of Bis(MPT)Mo by MobA
[MoVIO3(Lcat)]2−forms a Cu(i)-supported dimeric structure that spontaneously disproportionates into [MoVIO2(Lcat)2]2−and molybdate. This suggests a similar transformation of [{MoO3(MPT)}2]4−into [MoO2(MPT)2]2−by MobA is feasible.
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- Award ID(s):
- 2348382
- PAR ID:
- 10686500
- Publisher / Repository:
- RSC
- Date Published:
- Journal Name:
- Chemical Communications
- Volume:
- 62
- Issue:
- 25
- ISSN:
- 1359-7345
- Page Range / eLocation ID:
- 6773 to 6777
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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