TY - JOUR
T1 - Beyond the Active Site
T2 - Tuning the Activity and Selectivity of a Metal-Organic Framework-Supported Ni Catalyst for Ethylene Dimerization
AU - Liu, Jian
AU - Ye, Jingyun
AU - Li, Zhanyong
AU - Otake, Ken Ichi
AU - Liao, Yijun
AU - Peters, Aaron W.
AU - Noh, Hyunho
AU - Truhlar, Donald G.
AU - Gagliardi, Laura
AU - Cramer, Christopher J.
AU - Farha, Omar K.
AU - Hupp, Joseph T
PY - 2018/9/12
Y1 - 2018/9/12
N2 - To modify its steric and electronic properties as a support for heterogeneous catalysts, electron-withdrawing and electron-donating ligands, hexafluoroacetylacetonate (Facac-) and acetylacetonate (Acac-), were introduced to the metal-organic framework (MOF), NU-1000, via a process akin to atomic layer deposition (ALD). In the absence of Facac- or Acac-, NU-1000-supported, AIM-installed Ni(II) sites yield a mixture of C4, C6, C8, and polymeric products in ethylene oligomerization. (AIM = ALD-like deposition in MOFs). In contrast, both Ni-Facac-AIM-NU-1000 and Ni-Acac-AIM-NU-1000 exhibit quantitative catalytic selectivity for C4 species. Experimental findings are supported by density functional theory calculations, which show increases in the activation barrier for the C-C coupling step, due mainly to rearrangement of the siting of Facac- or Acac- to partially ligate added nickel. The results illustrate the important role of structure-tuning support modifiers in controlling the activity of MOF-sited heterogeneous catalysts and in engendering catalytic selectivity. The results also illustrate the ease with which crystallographically well-defined modifications of the catalyst support can be introduced when the node-coordinating molecular modifier is delivered via the vapor phase.
AB - To modify its steric and electronic properties as a support for heterogeneous catalysts, electron-withdrawing and electron-donating ligands, hexafluoroacetylacetonate (Facac-) and acetylacetonate (Acac-), were introduced to the metal-organic framework (MOF), NU-1000, via a process akin to atomic layer deposition (ALD). In the absence of Facac- or Acac-, NU-1000-supported, AIM-installed Ni(II) sites yield a mixture of C4, C6, C8, and polymeric products in ethylene oligomerization. (AIM = ALD-like deposition in MOFs). In contrast, both Ni-Facac-AIM-NU-1000 and Ni-Acac-AIM-NU-1000 exhibit quantitative catalytic selectivity for C4 species. Experimental findings are supported by density functional theory calculations, which show increases in the activation barrier for the C-C coupling step, due mainly to rearrangement of the siting of Facac- or Acac- to partially ligate added nickel. The results illustrate the important role of structure-tuning support modifiers in controlling the activity of MOF-sited heterogeneous catalysts and in engendering catalytic selectivity. The results also illustrate the ease with which crystallographically well-defined modifications of the catalyst support can be introduced when the node-coordinating molecular modifier is delivered via the vapor phase.
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U2 - 10.1021/jacs.8b06006
DO - 10.1021/jacs.8b06006
M3 - Article
C2 - 30141922
AN - SCOPUS:85052903912
VL - 140
SP - 11174
EP - 11178
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 36
ER -