Symmetry breaking in ligand-protected gold clusters probed by nonlinear optics

Abstract

The first hyperpolarizabilities of [Au25(SR)18](-1/0) and Au38(SR)24 clusters were determined by Hyper-Rayleigh Scattering. A strong dependence on the molecular symmetry was observed, and we explore two strategies to destroy the center of inversion in [Au25(SR)18](-1/0), protection by chiral ligands and alloying of the cluster with silver. This may open new avenues to applications of Au : SR clusters in second-order nonlinear optics.

Atomically precise clusters of gold and silver: A new class of nonlinear optical nanomaterials

“…For enhancing NLO efficiencies, innovative strategies should be explored in the future. To enhance second order χ (2) efficiencies, metal core-doping is a promising strategy as it distorts the metallic atom core 54 . Also, enhanced fluorescence of AuNCs by silver doping was reported by Le Guével et al 55,56 Therefore to enhance third order χ (3) efficiencies, silver doping can be coupled to ligand shell rigidity as the latter favors the radiative properties of AuNCs.…”

The molecular mechanism of the ligand exchange reaction of an antibody against a glutathione-coated gold cluster

“…As AuMPC we considered Au 25 (SG) 18 − , 16,17 a small and stable gold cluster with an 8-electron electronic shell closing. 18,19 Au 25 (SR) 18 − clusters have been widely used for ligand exchange reactions. [20][21][22][23][24][25][26] The fact that this cluster includes dimeric staple motifs 27 introduces a higher degree of complexity with respect to the reaction involving monomeric staples ( Fig.…”

Symmetry lowering by cage doping in spherical superatoms: Evaluation of electronic and optical properties of 18‐electron W@Au12Ptn (n = 0‐4) superatomic clusters from relativistic DFT calculations

“…Particularly, the doping of the cage results in a loss of the high icosahedral symmetry ( symmetry lowering ), which has been used toward the enhancing of optical properties, among other features. Our interest relies in the exploration of the cage doping, allowing the access to viable 18‐ e clusters related to [W@Au 12 ], introducing a decrease in symmetry by the inclusion of a heteroatom in the cage, which does not contribute formally to the overall electron count.…”

“…[44][45][46][47][48] Several clusters have been evaluated in analogy to this cluster taking advantage of the superatom model, [49][50][51][52][53][54][55][56][57][58][59] where the nature of the endohedral and cage atoms allows to modulate the total number of valence electrons. [42,52,55,59] Particularly, the doping of the cage results in a loss of the high icosahedral symmetry (symmetry lowering), which has been used toward the enhancing of optical properties, [60,61] among other features. Our interest relies in the exploration of the cage doping, allowing the access to viable 18-e clusters related to [W@Au 12 ], introducing a decrease in symmetry by the inclusion of a heteroatom in the cage, which does not contribute formally to the overall electron count.…”