Polymorphism of Phosphine‐Protected Gold Nanoclusters: Synthesis and Characterization of a New 22‐Gold‐Atom Cluster |
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Authors: | Qian‐Fan Zhang Paul G Williard Lai‐Sheng Wang |
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Affiliation: | Department of Chemistry, Brown University, Providence, RI, USA |
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Abstract: | A new Au22 nanocluster, protected by bis(2‐diphenyl‐phosphino)ethyl ether (dppee or C28H28OP2) ligand, has been synthsized and purified with high yield. Electrospray mass spectrometry shows that the new cluster has a formula of Au22(dppee)7, containing 22 gold atoms and seven dppee ligands. The cluster is found to be stable as a solid, but metastable in solution. The new cluster has been characterized by UV‐Vis‐NIR absorption spectroscopy, collision‐induced dissociation, and 31P‐NMR. The properties of the new cluster have been compared with the previous Au22(dppo)6 nanocluster (dppo = 1,8‐bis(diphenyl‐phosphino)octane or C32H36P2), which contains two fused Au11 units. All the experimental data indicate that the new Au22(dppee)7 cluster is different from the previously known Au22(dppo)6 cluster and represents a new Au22 core, which contains most likely one Au11 motif with several Au2(dppee) or Au(dppee) units. The Au22(dppee)7 cluster provides a new example of the ligand effects on the nuclearity and structural polymorphism of phosphine‐protected atom‐precise gold nanoclusters. |
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Keywords: | electrospray mass spectrometry gold nanoclusters NMR UV‐Vis‐NIR absorption |
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