Issue 33, 2020

Second-coordination sphere effects on the reactivities of Hoveyda–Grubbs-type catalysts: a ligand exchange study using phenolic moiety-functionalized ligands

Abstract

The Hoveyda–Grubbs (HG) second-generation catalyst (HG-II), a Ru complex with a 2-isopropoxybenzylidene ligand, is extensively used for olefin metathesis, the rearrangement of carbon–carbon double bonds. A well-known strategy to control its complex reactivity is to modify the phenyl ring in the ligand, thereby directly influencing the coordination of the phenolic oxygen to the metal center. We, herein, report that a functional group attached to the phenolic moiety in the 2-alkoxybenzylidene ligand can indirectly affect the reactivities of HG-type complexes. In this work, the ligand exchange reactions between HG-II and phenolic moiety-modified 2-alkoxybenzylidene ligands are useful for evaluating the structural effects of the ligands. Specifically, an ethylene amide or an ester group at the terminal phenolic moiety in the benzylidene ligand was found to influence the relative stabilities of HG-type complexes compared to that of the HG-II complex. The structural analyses proved that the observed effects of the functional groups on the complex stabilities originate from the interactions with a chlorido ligand in HG-type complexes without changes in coordination fashions at the metal centers. It was found that the outer-sphere interactions also influence the catalytic activities of HG-type complexes, namely, the properties of HG-type complexes can be controlled by outer-sphere structural factors toward the metal center (i.e., “the second-coordination sphere effect”). In the design of functionalized HG-type complexes, the outer-sphere structural effects need to be considered in addition to the optimization of the metal coordination site.

Graphical abstract: Second-coordination sphere effects on the reactivities of Hoveyda–Grubbs-type catalysts: a ligand exchange study using phenolic moiety-functionalized ligands

Supplementary files

Article information

Article type
Paper
Submitted
03 Jul 2020
Accepted
23 Jul 2020
First published
25 Jul 2020

Dalton Trans., 2020,49, 11618-11627

Second-coordination sphere effects on the reactivities of Hoveyda–Grubbs-type catalysts: a ligand exchange study using phenolic moiety-functionalized ligands

C. Jatmika, K. Goshima, K. Wakabayashi, N. Akiyama, S. Hirota and T. Matsuo, Dalton Trans., 2020, 49, 11618 DOI: 10.1039/D0DT02353A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements