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Selective molecular recognition by nanoscale environments in a supported iridium cluster catalyst

Okrut, Alexander and Runnebaum, Ron C. and Ouyang, Xiaoying and Lu, Jing and Aydin, Ceren and Hwang, Son-Jong and Zhang, Shengjie and Olatunji-Ojo, Olayinka A. and Durkin, Kathleen A. and Dixon, David A. and Gates, Bruce C. and Katz, Alexander (2014) Selective molecular recognition by nanoscale environments in a supported iridium cluster catalyst. Nature Nanotechnology, 9 (6). pp. 459-465. ISSN 1748-3387.

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The active sites of enzymes are contained within nanoscale environments that exhibit exquisite levels of specificity to particular molecules. The development of such nanoscale environments on synthetic surfaces, which would be capable of discriminating between molecules that would nominally bind in a similar way to the surface, could be of use in nanosensing, selective catalysis and gas separation. However, mimicking such subtle behaviour, even crudely, with a synthetic system remains a significant challenge. Here, we show that the reactive sites on the surface of a tetrairidium cluster can be controlled by using three calixarene–phosphine ligands to create a selective nanoscale environment at the metal surface. Each ligand is 1.4 nm in length and envelopes the cluster core in a manner that discriminates between the reactivities of the basal-plane and apical iridium atoms. CO ligands are initially present on the clusters and can be selectively removed from the basal-plane sites by thermal dissociation and from the apical sites by reactive decarbonylation with the bulky reactant trimethylamine-N-oxide. Both steps lead to the creation of metal sites that can bind CO molecules, but only the reactive decarbonylation step creates vacancies that are also able to bond to ethylene, and catalyse its hydrogenation.

Item Type:Article
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URLURL TypeDescription material ReadCube access
Okrut, Alexander0000-0002-0689-4346
Hwang, Son-Jong0000-0002-3210-466X
Dixon, David A.0000-0002-9492-0056
Gates, Bruce C.0000-0003-0274-4882
Katz, Alexander0000-0003-3487-7049
Additional Information:© 2014 Macmillan Publishers Limited. Received 29 July 2013; Accepted 12 March 2014; Published online 20 April 2014. The authors declare no competing financial interests. The authors acknowledge financial support from the Management and Transfer of Hydrogen via Catalysis Program funded by Chevron Corporation (to A.O. and X.O.) and the US Department of Energy, Office of Science, Basic Energy Sciences (contract no. DE-SC0005822, to J.L., C.A., B.G., R.R., A.K., S.Z. and D.D.). The NMR facility at Caltech was supported by the National Science Foundation (NSF; grant no. 9724240) and partially supported by the MRSEC Program of the NSF (award no. DMR-520565; to S.H.). Electron microscopy work was supported by the Department of Energy (DOE; Basic Energy Sciences grant no. DE-FG02-03ER46057, to C.A.) and the University of California Lab Fee Program. The Molecular Graphics and Computation Facility at UC Berkeley was supported by the NSF (award no. CHE 0840505, to O.O. and K.D.).
Funding AgencyGrant Number
Chevron CorporationUNSPECIFIED
Department of Energy (DOE)DE-SC0005822
Department of Energy (DOE)DE-FG02-03ER46057
University of California Lab Fees Research ProgramUNSPECIFIED
Issue or Number:6
Record Number:CaltechAUTHORS:20140429-115453519
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Official Citation:Okrut, A., Runnebaum, R. C., Ouyang, X., Lu, J., Aydin, C., Hwang, S.-J., . . . Katz, A. (2014). Selective molecular recognition by nanoscale environments in a supported iridium cluster catalyst. [Article]. Nature Nanotechnology 9, 459–465 (2014) doi:10.1038/nnano.2014.72
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:45303
Deposited By: Aucoeur Ngo
Deposited On:29 Apr 2014 19:12
Last Modified:09 Mar 2020 13:19

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