Ruthenium(II) Complexes of a Xanthene-Spanned Dicarbene Ligand
Octahedral ruthenium(II) complexes of a xanthene-di(N-heterocyclic carbene) ancillary ligand (XdC) have been prepared and structurally characterized. Examples catalyze the transfer hydrogenation of ketones {[Ru(CO)I2(C,O,C′-XdC)] (1) and [Ru(CO)(MeCN)2(C,O,C′-XdC)]2+ (2 2+ )} and the selective...
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| Published in: | Inorganic chemistry Vol. 62; no. 46; pp. 18901 - 18914 |
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| Main Authors: | , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
American Chemical Society
20-11-2023
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| Online Access: | Get full text |
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| Summary: | Octahedral ruthenium(II) complexes of a xanthene-di(N-heterocyclic carbene) ancillary ligand (XdC) have been prepared and structurally characterized. Examples catalyze the transfer hydrogenation of ketones {[Ru(CO)I2(C,O,C′-XdC)] (1) and [Ru(CO)(MeCN)2(C,O,C′-XdC)]2+ (2 2+ )} and the selective electrochemical reduction of CO2 to CO {[Ru(N,N′-bpy)(CO)(C,O,C′-XdC)]2+ (3 2+ ) at 0.40 V overpotential in MeCN–H2O (1 M)}. The reaction of 1 with KBEt3H afforded isomers of [(C,C′-XdC)Ru(μ-H)(H)]2 dimers, which are stable to reductive elimination of the XdC ligand, thereby suggesting similar (XdC)Rh(coligand)(H) x species may be viable intermediates in catalyses. The electrochemical reduction of CO2 involves a double reduction of 3 2+ to 3 •• , which has been characterized by IR-SEC and DFT calculations. The DFT calculations suggest the Ru–Oxanth bond breaks in 3 •• , opening a metal site for CO2 binding with selectivity over protons enabled by the diffuse nature of the HOMO delocalized over the metal and the bipyridine and carbonyl coligands. The results point to the promise of metal complexes of flexible and hemilabile xanthene-(NHC)2 ancillary ligands in catalysis. |
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| Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
| ISSN: | 0020-1669 1520-510X |
| DOI: | 10.1021/acs.inorgchem.3c02348 |