Ligand accommodation causes the anti-centrosymmetric structure of Au13Cu4 clusters with near-infrared emission. Issue 27 (6th July 2020)

• Record Type: Journal Article
• Authors: Anumula, Rajini; Reber, Arthur C.; An, Pan; Cui, Chaonan; Guo, Mengdi; Wu, Haiming; Luo, Zhixun; Khanna, Shiv. N.
• Is Part Of: Nanoscale. Volume 12:Issue 27(2020)
• Page Start: 14801
• Page End: 14807
• Publication Date: 2020-07-06
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/d0nr02448a
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : We synthesized an [Au13 Cu4 (PPh3 )4 (SPy)8 ] + nanocluster co-capped by phosphine and thiolate ligands. Abstract : We synthesized an [Au13 Cu4 (PPh3 )4 (SPy)8 ] + nanocluster co-capped by phosphine and thiolate ligands. Interestingly, this Au13 Cu4 cluster corresponds to an anti-centrosymmetric structure with the four copper atoms coordinated to the mixed ligands on the same side of the Au13 icosahedron, which is in sharp contrast to the [Au13 Cu4 (PPh2 Py)4 (SPh t Bu)8 ] + and [Au13 Cu2 (PPh3 )6 (SPy)6 ] + clusters which possess highly symmetric structures with well-separated Cu adatoms. Both [Au13 Cu4 (PPh3 )4 (SPy)8 ] + and [Au13 Cu2 (PPh3 )6 (SPy)6 ] + clusters correspond to 8 valence electron superatoms with large HOMO–LUMO gaps, respectively. The difference in structure is rooted in the nature of the mixed ligands, with the bidentate SPy binding strongly to Cu on both binding sites (–N–Cu and Au-SR-Cu) leading to the co-linking of adjacent Cu atoms, while the bidentate PPh2 Py binds Cu on one site and Au on the other giving rise to a separation of the Cu atoms even in the presence of relatively higher monomer concentration. Both [Au13 Cu4 (PPh3 )4 (SPy)8 ] + and [Au13 Cu2 (PPh3 )6 (SPy)6 ] + display emissions in the near-IR regions. TD-DFT calculations reproduce the spectroscopic results with specified excited states, shedding light on the geometric and electronic behaviors of the ligand-protected Au13 M x clusters.