Identification of a Highly Luminescent Au₂₂(SG)₁₈ Nanocluster

Abstract

The luminescence property of thiolated gold nanoclusters (Au NCs) is thought to involve the Au(I)-thiolate motifs on the NC surface; however, this hypothesis remains largely unexplored because of the lack of precise molecular composition and structural information of highly luminescent Au NCs. Here we report a new red-emitting thiolated Au NC, which has a precise molecular formula of Au22(SR)18 and exhibits intense luminescence. Interestingly, this new Au22(SR)18 species shows distinctively different absorption and emission features from the previously reported Au22(SR)16, Au22(SR)17, and Au25(SR)18. In stark contrast, Au22(SR)18 luminesces intensely at ∼665 nm with a high quantum yield of ∼8%, while the other three Au NCs show very weak luminescence. Our results indicate that the luminescence of Au22(SR)18 originates from the long Au(I)-thiolate motifs on the NC surface via the aggregation-induced emission pathway. Structure prediction by density functional theory suggests that Au22(SR)18 has two RS-[Au-SR]3 and two RS-[Au-SR]4 motifs, interlocked and capping on a prolate Au8 core. This predicted structure is further verified experimentally by Au L3-edge X-ray absorption fine structure analysis.

Zwitterion functionalized gold nanoclusters for multimodal near infrared fluorescence and photoacoustic imaging

“…[20][21][22] Au NCs stabilized by glutathione (GSH) are probably one of the most described NCs in the literature with a precise control of their size and their structure. [23][24][25][26] The natural peptide GSH has a zwitterionic structure and, when coated on the particle surface, could prevent the detection by a Author to whom correspondence should be addressed. Electronic mail: xavier.le-guevel@univ-grenoble-alpes.fr macrophages.…”

Multivalent Glycosylation of Fluorescent Gold Nanoclusters Promotes Increased Human Dendritic Cell Targeting via Multiple Endocytic Pathways

“…. In the latter example, extensive experimental studies supported by theoretical models 30,35 demonstrate that both the NC core and the thiolated gold (I) shell contribute to their photoluminescence properties, with the shell being especially important for red-NIR region emissions [36][37][38][39] . For instance, the Mattoussi lab reported the preparation of red-emitting Au NCs with a quantum yield of up to 14% when stabilised with bidentate thiolated ligands containing a zwitterionic group 40 .…”

Advanced AuNMs as nanomedicine’s central goals capable of active targeting in both imaging and therapy in biomolecules

“…In order to further control the luminescence property, synthesis of atomically precise AuNCs has ignited numerous research efforts [42,43]. In 2014, Yu et al [44] synthesized Au 22 (glutathione) 18 clusters of the emission peak at ∼665 nm with a QY of ∼8%. Upon comparison of their luminescence properties with those of Au (I)-thiolate complexes, the enhanced luminescence of Au 22 (SG) 18 was ascribed to aggregation-induced emission.…”