TY - JOUR
T1 - Activation of Low-Valent, Multiply M-M Bonded Group VI Dimers toward Catalytic Olefin Metathesis via Surface Organometallic Chemistry
AU - Chapovetsky, Alon
AU - Langeslay, Ryan R.
AU - Celik, Gokhan
AU - Perras, Frédéric A.
AU - Pruski, Marek
AU - Ferrandon, Magali S.
AU - Wegener, Evan C.
AU - Kim, Hacksung
AU - Dogan, Fulya
AU - Wen, Jianguo
AU - Khetrapal, Navneet
AU - Sharma, Prachi
AU - White, Jacob
AU - Kropf, A. Jeremy
AU - Sattelberger, Alfred P.
AU - Kaphan, David M.
AU - Delferro, Massimiliano
N1 - Funding Information:
This work was supported by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences, Catalysis Science Program under contract nos. DE-AC-02-06CH11357 (Argonne National Laboratory) and DE-AC02-07CH11358 (Ames Laboratory). Use of the Advanced Photon Source was supported by the U.S. DOE, Office of Science, and Office of the Basic Energy Sciences, under contract no. DE-AC-02-06CH11357. MRCAT operations were supported by the DOE and the MRCAT member institutions. Use of the TEM at the Center for Nanoscale Materials at Argonne National Laboratory is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract no. DE-AC-02-06CH11357. The computational work was supported by the Inorganometallic Catalyst Design Center, an EFRC funded by the DOE, Office of Basic Energy Sciences (DE-SC0012702). P.S. acknowledges a doctoral dissertation fellowship from the University of Minnesota. H.K (UV Raman work) was supported by the US Department of Energy, Office of Basic Energy Sciences, through grant no. DE-FG02-03ER15457 to the Institute for Catalysis for Energy Processes (ICEP) at Northwestern University. F.K.D. acknowledges support from the Vehicle Technologies Office at the U.S. Department of Energy Efficiency and Renewable Energy
Funding Information:
This work was supported by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences Catalysis Science Program under contract nos. DE-AC-02-06CH11357 (Argonne National Laboratory) and DE-AC02-07CH11358 (Ames Laboratory). Use of the Advanced Photon Source was supported by the U.S. DOE, Office of Science, and Office of the Basic Energy Sciences, under contract no. DE-AC-02-06CH11357. MRCAT operations were supported by the DOE and the MRCAT member institutions. Use of the TEM at the Center for Nanoscale Materials at Argonne National Laboratory is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract no. DE-AC-02-06CH11357. The computational work was supported by the Inorganometallic Catalyst Design Center an EFRC funded by the DOE, Office of Basic Energy Sciences (DE-SC0012702). P.S. acknowledges a doctoral dissertation fellowship from the University of Minnesota. H.K (UV Raman work) was supported by the US Department of Energy, Office of Basic Energy Sciences, through grant no. DE-FG02-03ER15457 to the Institute for Catalysis for Energy Processes (ICEP) at Northwestern University. F.K.D. acknowledges support from the Vehicle Technologies Office at the U.S. Department of Energy Efficiency and Renewable Energy.
Publisher Copyright:
© 2020 American Chemical Society.
PY - 2020/4/13
Y1 - 2020/4/13
N2 - Olefin metathesis is a broadly employed reaction with applications that range from fine chemicals to materials and petrochemicals. The design and investigation of olefin metathesis catalysts have been ongoing for over half a century, with advancements made in terms of activity, stability, and selectivity. Immobilization of organometallic complexes onto solid supports such as silica or alumina is a promising strategy for catalyst heterogenization, often resulting in increased activity and stability. Consequently, a broad range of early transition metal catalysts bearing alkyl, oxide/alkoxide, and amide ligands have been grafted onto silica and their reactivities investigated. Herein, we report a series of silica-supported tungsten and molybdenum dimers (X3MMX3, where M = W and Mo; X = neopentyl, tert-butoxide, and dimethyl amide) and their reactivities toward catalytic olefin metathesis. Dynamic nuclear polarization (DNP)-enhanced solid-state nuclear magnetic resonance (SSNMR), diffuse reflectance infrared Fourier transform (DRIFT), UV resonance Raman, and X-ray absorption (XAS) spectroscopies suggest that upon heterogenization the dimers bind to the surface in a monopodal fashion, with the MM triple bond remaining intact. These structural assignments were further corroborated by density functional theory (DFT) calculations. While the homogeneous dimer counterparts are inert, the supported low-valent alkyl W and Mo dimers become active for the disproportionative self-metathesis of propylene to ethylene and butenes and 4-nonene to 4-octene and 5-decene under mild conditions. The lack of activity observed for the free and supported tert-butoxide and dimethyl amide dimers likely suggests that the neopentyl groups are necessary for the formation of a putative alkylidene active species. The difference in reactivity between the free and supported dimers could be explained either by the lowering of the activation barrier of the complex through the electronic effects of the surface or by site isolation of catalytically relevant reactive intermediates.
AB - Olefin metathesis is a broadly employed reaction with applications that range from fine chemicals to materials and petrochemicals. The design and investigation of olefin metathesis catalysts have been ongoing for over half a century, with advancements made in terms of activity, stability, and selectivity. Immobilization of organometallic complexes onto solid supports such as silica or alumina is a promising strategy for catalyst heterogenization, often resulting in increased activity and stability. Consequently, a broad range of early transition metal catalysts bearing alkyl, oxide/alkoxide, and amide ligands have been grafted onto silica and their reactivities investigated. Herein, we report a series of silica-supported tungsten and molybdenum dimers (X3MMX3, where M = W and Mo; X = neopentyl, tert-butoxide, and dimethyl amide) and their reactivities toward catalytic olefin metathesis. Dynamic nuclear polarization (DNP)-enhanced solid-state nuclear magnetic resonance (SSNMR), diffuse reflectance infrared Fourier transform (DRIFT), UV resonance Raman, and X-ray absorption (XAS) spectroscopies suggest that upon heterogenization the dimers bind to the surface in a monopodal fashion, with the MM triple bond remaining intact. These structural assignments were further corroborated by density functional theory (DFT) calculations. While the homogeneous dimer counterparts are inert, the supported low-valent alkyl W and Mo dimers become active for the disproportionative self-metathesis of propylene to ethylene and butenes and 4-nonene to 4-octene and 5-decene under mild conditions. The lack of activity observed for the free and supported tert-butoxide and dimethyl amide dimers likely suggests that the neopentyl groups are necessary for the formation of a putative alkylidene active species. The difference in reactivity between the free and supported dimers could be explained either by the lowering of the activation barrier of the complex through the electronic effects of the surface or by site isolation of catalytically relevant reactive intermediates.
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U2 - 10.1021/acs.organomet.9b00787
DO - 10.1021/acs.organomet.9b00787
M3 - Article
AN - SCOPUS:85083921195
VL - 39
SP - 1035
EP - 1045
JO - Organometallics
JF - Organometallics
SN - 0276-7333
IS - 7
ER -