Vivancos Á, Petronilho A, Cardoso J, Müller-Bunz H, Albrecht M. Unveiling the role of ancillary ligands in acceptorless benzyl alcohol dehydrogenation and etherification mediated by mesoionic carbene iridium complexes.
Dalton Trans 2017;
47:74-82. [PMID:
29200225 DOI:
10.1039/c7dt04109h]
[Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We synthesized a set of triazolylidene iridium(iii) complexes [IrCp*(C^N)L]n+ (Cp* = pentamethylcyclopentadienyl, C^N = C,N-bidentate coordinating pyridyl-triazolylidene) containing different neutral or anionic ancillary ligands L and evaluated their impact on the catalytic activity in alcohol conversion. We demonstrate that these ancillary ligands have a strong influence on the catalytic selectivity and direct whether the iridium center preferentially catalyzes either the dehydrogenation or the dehydration of benzyl alcohol. Ligand exchange experiments provide a direct correlation of ligand lability with catalytic activity and selectivity. These results underline the relevance of ancillary ligands and provide a rational approach to tailor the catalytic activity of the iridium center towards aldehyde formation (loss of H2) or etherification (elimination of H2O).
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