Investigating the X-type Ligand

The biggest difference in the measured initiation rate constants was between catalysts containing monodentate (k ) and bidentate (k ) ligands. For example, catalysts with ligands initiated very slowly (13), or were almost completely inactive (14). This result was in stark contrast to traditional, non-C-H-activated catalysts, which do not display such a significant effect [29-32]. On the opposite end of the spectrum, catalysts with large carboxylate ligands initiated relatively fast. In fact, the initiation rate constant for 8 was within error of that measured for 1 under identical conditions [26]. 

It is worth noting that the performance of other Ru-based, Z-selective catalysts was also found to depend on the nature of the X-type ligand. For example, the 

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