Effect of the Bulkiness of Indenylidene Moieties on the Catalytic Initiation and Efficiency of Second-Generation Ruthenium-Based Olefin Metathesis Catalysts
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Date
2016
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Abstract
We report on the synthesis and characterization of the second generation of ruthenium catalysts bearing various sized
indenylidene ligands, denoted as RuCl2(3-(2,6-xylyl)-1-indenylidene)(SIMes)(PCy3) 5a, RuCl2(4-methyl-3-(o-tolyl)-1-
indenylidene)(SIMes)(PCy3) 5b, RuCl2(3-1-naphthyl-1-indenylidene)(SIMes)(PCy3) 5c and RuCl2(3-(p-fluorophenyl)-1-
indenylidene)(SIMes)(PCy3) 5d. The obtained complexes were characterized by NMR, IR, HRMS and elemental analysis.
Moreover, the configurations of complexes 5a, 5b and 5d were confirmed by single-crystal X-ray diffraction analysis. The
catalytic performance of the obtained complexes 5a-d were evaluated in several olefin metathesis reactions: the RCM of
substrates 6 and 7, the RCEYM of substrate 8 and the ROMP of COD in comparison with the commercially available catalyst
3a. Careful analysis of the catalysts performance and single-crystal X-ray diffraction data of the obtained complexes
reveals that the steric modification on the 3-phenyl group can have an obvious influence on the ligands congestion around
the ruthenium center and hence, alters the catalytic activities in metathesis reactions. Additionally, the better performing
complex 5a was further investigated in the RCM of substrate 6 in comparison with complex 3c and bench mark complexes
1b, 2 and 3a.
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Yu, B., Luo, Z., Hamad, F.B., Leus, K., van Hecke, K. and Verpoort, F., 2016. Effect of the bulkiness of indenylidene moieties on the catalytic initiation and efficiency of second-generation ruthenium-based olefin metathesis catalysts. Catalysis Science & Technology.