Reversible Bimetallic Inhibition to Modulate Selectivity During Catalysis
Bimetallic complexes have demonstrated a great ability to enhance the activity of monometallic systems for bond activation and catalysis. In this work, we explore the opposite approach: using a second metal to passivate the activity of another by reversible bimetallic inhibition. To do so we have sy...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/415376 |
| Acceso en línea: | http://hdl.handle.net/10261/415376 https://api.elsevier.com/content/abstract/scopus_id/85212785193 |
| Access Level: | acceso abierto |
| Palabra clave: | Bimetals Catalysts Gold Hydrocarbons Transition metals |
| Sumario: | Bimetallic complexes have demonstrated a great ability to enhance the activity of monometallic systems for bond activation and catalysis. In this work, we explore the opposite approach: using a second metal to passivate the activity of another by reversible bimetallic inhibition. To do so we have synthesized a family of nine electrophilic gold complexes of formula Au(PR3)(NTf2) ([NTf2]- = [N(SO2CF3)2]-) that can act as inhibitors in the semihydrogenation of terminal and internal alkynes catalyzed by the iconic iridium Vaska complex IrCl(CO)(PPh3)2. This behavior parallels the well-known passivation effect of lead over palladium in the heterogeneous Lindlard catalyst. Most gold fragments, except for the most hindered, form metal-only Lewis pairs upon combination with iridium, which have been fully characterized and exhibit distinct dative Ir → Au bonds. When applied to alkyne hydrogenation, these bimetallic structures have a clear tendency toward olefin formation, while the monometallic catalyst unselectively leads to overreduction products. Our computational studies not only provide a feasible mechanism for the Ir-only system, but also evince the active role of gold in passivating iridium by reversibly forming heterobimetallic structures that lead to enhanced selectivity. |
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