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Creators/Authors contains: "Janzen, Daron E."

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  1. null (Ed.)
  2. Abstract

    A metal/ligand cooperative approach to the reduction of small molecules by metal silylene complexes (R2Si=M) is demonstrated, whereby silicon activates the incoming substrate and mediates net two‐electron transformations by one‐electron redox processes at two metal centers. An appropriately tuned cationic pincer cobalt(I) complex, featuring a central silylene donor, reacts with CO2to afford a bimetallic siloxane, featuring two CoIIcenters, with liberation of CO; reaction of the silylene complex with ethylene yields a similar bimetallic product with an ethylene bridge. Experimental and computational studies suggest a plausible mechanism proceeding by [2+2] cycloaddition to the silylene complex, which is quite sensitive to the steric environment. The CoII/CoIIproducts are reactive to oxidation and reduction. Taken together, these findings demonstrate a strategy for metal/ligand cooperative small‐molecule activation that is well‐suited to 3dmetals.

     
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  3. Abstract

    A metal/ligand cooperative approach to the reduction of small molecules by metal silylene complexes (R2Si=M) is demonstrated, whereby silicon activates the incoming substrate and mediates net two‐electron transformations by one‐electron redox processes at two metal centers. An appropriately tuned cationic pincer cobalt(I) complex, featuring a central silylene donor, reacts with CO2to afford a bimetallic siloxane, featuring two CoIIcenters, with liberation of CO; reaction of the silylene complex with ethylene yields a similar bimetallic product with an ethylene bridge. Experimental and computational studies suggest a plausible mechanism proceeding by [2+2] cycloaddition to the silylene complex, which is quite sensitive to the steric environment. The CoII/CoIIproducts are reactive to oxidation and reduction. Taken together, these findings demonstrate a strategy for metal/ligand cooperative small‐molecule activation that is well‐suited to 3dmetals.

     
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  4. The synthesis and characterization of base-stabilized and base-free pincer-type bis(phosphine)/silylene [P 2 Si]Ru complexes are reported. The base-free complex readily reduces CO 2 and CS 2 via silylene-assisted hydride transfer, affording structurally distinct products with silicon-to-ruthenium formate and dithioformate bridges. 
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  5. The title compound, [Mo(C 5 H 5 )(C 2 H 3 O)(C 24 H 27 P)(CO) 2 ], was prepared by reaction of [Mo(C 5 H 5 )(CO) 3 (CH 3 )] with tris(3,5-dimethylphenyl)phosphane. The complex exhibits a four-legged piano-stool geometry with trans -disposed acetyl and phosphane ligands. The molecular geometry is nearly identical to that of the triphenylphosphane derivative, but introduction of methyl groups on the aromatic phosphane substituents significantly impacts supramolecular organization. In the crystal, non-classical C—H...O interactions involving the acetyl carbonyl group lead to a chain motif along [010], and another set of C—H...O close contacts join inversion-related molecules. 
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