The reactivity of phosphaalkynes, the isolobal and isoelectronic congeners to alkynes, with metal alkylidyne complexes is explored in this work. Treating the tungsten alkylidyne [
This content will become publicly available on July 1, 2025
- Award ID(s):
- 2154377
- PAR ID:
- 10530843
- Publisher / Repository:
- Elsevier
- Date Published:
- Journal Name:
- Polyhedron
- Volume:
- 256
- Issue:
- C
- ISSN:
- 0277-5387
- Page Range / eLocation ID:
- 116987
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
Abstract t BuOCO]W≡Ct Bu(THF)2(1 ) with phosphaalkyne (10 ) results in the formation of [O2C(t BuC=)W{η 2‐(P ,C )−P≡C−Ad}(THF)] (13‐ t BuTHF ) and [O2C(AdC=)W{η 2‐(P ,C )−P≡C−t Bu}(THF)] (13‐AdTHF ); derived from the formal reductive migratory insertion of the alkylidyne moiety into a W−Carenebond. Analogous to alkyne metathesis, a stable phosphametallacyclobutadiene complex [t BuOCO]W[κ 2‐C(t Bu)PC(Ad)] (14 ) forms upon loss of THF from the coordination sphere of either13‐ t BuTHF or13‐AdTHF . Remarkably, the C−C bonds reversibly form/cleave with the addition or removal of THF from the coordination sphere of the formal tungsten(VI) metal center, permitting unprecedented control over the transformation of a tetraanionic pincer to a trianionic pincer and back. Computational analysis offers thermodynamic and electronic reasoning for the reversible equilibrium between13‐ t Bu/AdTHF and14 . -
Abstract The reactivity of phosphaalkynes, the isolobal and isoelectronic congeners to alkynes, with metal alkylidyne complexes is explored in this work. Treating the tungsten alkylidyne [
t BuOCO]W≡Ct Bu(THF)2(1 ) with phosphaalkyne (10 ) results in the formation of [O2C(t BuC=)W{η 2‐(P ,C )−P≡C−Ad}(THF)] (13‐ t BuTHF ) and [O2C(AdC=)W{η 2‐(P ,C )−P≡C−t Bu}(THF)] (13‐AdTHF ); derived from the formal reductive migratory insertion of the alkylidyne moiety into a W−Carenebond. Analogous to alkyne metathesis, a stable phosphametallacyclobutadiene complex [t BuOCO]W[κ 2‐C(t Bu)PC(Ad)] (14 ) forms upon loss of THF from the coordination sphere of either13‐ t BuTHF or13‐AdTHF . Remarkably, the C−C bonds reversibly form/cleave with the addition or removal of THF from the coordination sphere of the formal tungsten(VI) metal center, permitting unprecedented control over the transformation of a tetraanionic pincer to a trianionic pincer and back. Computational analysis offers thermodynamic and electronic reasoning for the reversible equilibrium between13‐ t Bu/AdTHF and14 . -
2-(Arylamino)-4,6-di- tert -butylphenols containing 4-substituted phenyl groups ( R apH 2 ) react with oxobis(ethylene glycolato)osmium( vi ) in acetone to give square pyramidal bis(amidophenoxide)oxoosmium( vi ) complexes. A mono-amidophenoxide complex is observed as an intermediate in these reactions. Reactions in dichloromethane yield the diolate ( H ap) 2 Os(OCH 2 CH 2 O). Both the glycolate and oxo complex are converted to the corresponding cis -dichloride complex on treatment with chlorotrimethylsilane. The novel bis(aminophenol) ligand EganH 4 , containing an ethylene glycol dianthranilate bridge, forms the chelated bis(amidophenoxide) complex (Egan)OsO, where the two nitrogen atoms of the tetradentate ligand bind in the trans positions of the square pyramid. Structural and spectroscopic features of the complexes are described well by an osmium( vi )-amidophenoxide formulation, with the amount of π donation from ligand to metal increasing markedly as the co-ligands change from oxo to diolate to dichloride. In the oxo-bis(amidophenoxides), the symmetry of the ligand π orbitals results in only one effective π donor interaction, splitting the energy of the two osmium-oxo π* orbitals and rendering the osmium-oxo bonding appreciably anisotropic.more » « less
-
Abstract Catalysis of
O ‐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 from2 to produce mono‐oxo complex (cy‐salen)Mo(IV)O (3 ); 3) stepwise O2association with3 via 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 species5 at 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 triplet3 7 or singlet1 7 by a concerted, asynchronous electronic isomerization. An alternative pathway for recycling of the oxo‐peroxo species5 to the dioxo‐Mo1 via a bimetallic peroxo complex LMo(O)‐O−O‐Mo(O)L8 is determined to be energetically viable, but is unlikely to be competitive with the primary pathway for aerobic phosphine oxidation catalyzed by1 .