Physical Chemistry, Short Talk
PC-021

Dynamic Studies of Au-doped Ag29 Nanocluster

S. Kundu1, T. Bürgi1*
1Department of Physical Chemistry, 30 Quai Ernest-Ansermet, University of Geneva, 1211 Geneva 4, Switzerland

Nuclear Magnetic Resonance (NMR) spectroscopy[1] is a powerful tool to  study the structure and dynamics of all sorts of chemical compounds including atomically precise gold[2-3] and silver nanoclusters.[4,5] For example, some of us have recently studied the intracluster ligand dynamics for the Ag25 and single atom doped Ag24Au nanoclusters using NMR spectroscopy.[4,5] In this poster presentation, I will discuss the structure and properties of Ag29(BDT)12(TPP)4 and Ag29-x Aux (BDT)12(TPP)4 NCs (BDT = 1,3-benzenedithiol, TPP = Triphenyl phosphine).[6] I will focus explicitly on the dynamic properties of the metal core and the ligand shell using by NMR spectroscopy (1H, 31P and 109Ag) at different temperatures (Figure 1). The phosphine ligands are very dynamic at room temperature, desorbing from and re-adsorbing onto the cluster rapidly. At low temperatures the appearance of different 31P NMR signals indicates a lowering of the cluster symmetry. Electronic structure calculations indicate that the origin of this symmetry breaking is a pseudo Jahn-Teller effect, which could influence the photophysical properties of these nanoclusters, such as photoinduced electron transfer (PET) processes.[7]

Figure 1. 109Ag (a) and 31P (b) NMR of Au doped (0 to 20%) and undoped Ag29 nanoclusters at 298 (a) and 223 K (b). 31P VT NMR of undoped Ag29 (c) and 10 % Au doped Ag29 (d) nanoclusters: 223 K to 298 K.

[1]  G. Salassa, T. Bürgi, Nanoscale Horizons 2018, 3, 457–463.
[2]  G. Salassa, A. Sels, F. Mancin, T. Bürgi, ACS Nano 2017, 11, 12609–12614.
[3]  L. Riccardi, F. De Biasi, M. De Vivo, T. Bürgi, F. Rastrelli, G. Salassa, ACS Nano 2019, 13, 7127–7134.
[4]  G. Salassa, K. R. Krishnadas, M. Pupier, J. Viger-Gravel, T. Bürgi, J. Phys. Chem. C 2021, 125, 2524–2530.
[5]  D. Rosa-Gastaldo, M. Pupier, G. Meshvildishvili, J. Viger-Gravel, T. Bürgi, Nanoscale 2023, 15, 6838–6843.
[6]  G. Soldan, M. A. Aljuhani, M. S. Bootharaju, L. G. AbdulHalim, M. R. Parida, A. Emwas, O. F. Mohammed, O. M. Bakr, Angew. Chemie 2016, 128, 5843–5847.
[7]  X. M. Luo, C. H. Gong, F. Pan, Y. Si, J. W. Yuan, M. Asad, X. Y. Dong, S. Q. Zang, T. C. W. Mak, Nat. Commun. 2022, 13, 1–8.