Biomimetic crystallization for long-pursued -COOH-functionalized gold nanocluster with near-infrared phosphorescence

Wei-Dong Tian; Wei-Dan Si; Shana Havenridge; Chengkai Zhang; Zhi Wang; Christine M Aikens; Chen-Ho Tung; Di Sun

doi:10.1016/j.scib.2023.11.014

Biomimetic crystallization for long-pursued -COOH-functionalized gold nanocluster with near-infrared phosphorescence

Sci Bull (Beijing). 2024 Jan 15;69(1):40-48. doi: 10.1016/j.scib.2023.11.014. Epub 2023 Nov 7.

Authors

Wei-Dong Tian¹, Wei-Dan Si¹, Shana Havenridge², Chengkai Zhang¹, Zhi Wang¹, Christine M Aikens², Chen-Ho Tung¹, Di Sun³

Affiliations

¹ School of Chemistry and Chemical Engineering, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China.
² Department of Chemistry, Kansas State University, Manhattan KS 66506, USA.
³ School of Chemistry and Chemical Engineering, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China. Electronic address: dsun@sdu.edu.cn.

PMID: 37985311
DOI: 10.1016/j.scib.2023.11.014

Abstract

As an interdisciplinary product, water-soluble gold nanoclusters (AuNCs) stabilized by ligands containing carboxyl (-COOH) group have garnered significant attention from synthetic chemists and biologists due to their immense potential for biomedical applications. However, revealing the crystallographic structures of -COOH-functionalized AuNCs remains a bottleneck. Herein, we successfully applied the salting-out method to obtain a series of high-quality single crystals of -COOH-functionalized Au₂₅ nanoclusters and revealed their crystallographic structures. Particularly, K₃Au₂₅(2-Hmna)₉(mna)₆]^- (Au25a) protected by 2-mercaptonicotinic acid features an unprecedented tetrameric Au₄(SR^S)₃(SR^S,N)₂ staple motifs surrounding the icosahedral Au₁₃ kernel, breaking the traditional perception on the structure of Au₂₅(SR)₁₈. Au25a exhibits a distinct near-infrared emission at 970 nm with long lifetime of 8690 ns, which have been studied by transient absorption spectroscopy and time-dependent density functional theory. This work compensates for the research gap in the experimental structure of -COOH-functionalized AuNCs and opens up a new avenue to explore their structure-property correlations.

Keywords: Near-infrared phosphorescence; Salting-out method; Water-soluble gold nanoclusters.