Thiolate-protected atomically precise nanoclusters (NCs) demonstrate a series of unique luminescent characteristics attributed to their various peculiar electronic structures. Therefore, fluorescent NCs present extraordinary practical values in biosensing and bioimaging research fields. Nevertheless, restricted by the types of fluorescent NCs, there are great difficulties in promoting the development of NCs in fluorescent research areas. As a result, it is of significant necessity for researchers to develop new synthetic pathways to produce high-quality fluorescent NCs. According to the analysis about the structural characteristics of fluorescent NCs, some general features like longer motif and higher ligand-to-metal ratio can be found, consistent to some presented regularities in etching reaction. Consequently, in this work, we used Au25(MHA)18 (MHA = 6-mercaptohexanoic acid) as a model nanocluster and utilized the etching reaction to systematically explore etching products and their corresponding luminescent properties. Moreover, we also identified three main reaction processes in the entire etching reaction process, which can generate new metal nanocluster species with various fluorescent properties. Hence, the etching reaction will provide a good platform to produce new luminescent metal NC species.
Wu, Z. N.; Yao, Q. F.; Zang, S. Q.; Xie, J. P. Directed self-assembly of ultrasmall metal nanoclusters. ACS Mater. Lett. 2019, 1, 237–248.
Aires, A.; Llarena, I.; Moller, M.; Castro-Smirnov, J.; Cabanillas-Gonzalez, J.; Cortajarena, A. L. A simple approach to design proteins for the sustainable synthesis of metal nanoclusters. Angew. Chem., Int. Ed. 2019, 58, 6214–6219.
Xiao, Y.; Wu, Z. N.; Yao, Q. F.; Xie, J. P. Luminescent metal nanoclusters: Biosensing strategies and bioimaging applications. Aggregate 2021, 2, 114–132.
Schmid, G. Nanoclusters-building blocks for future nanoelectronic devices. 3.0.CO;2-8">Adv. Eng. Mater. 2001, 3, 737–743.
Chen, L. Y.; Wang, C. W.; Yuan, Z. Q.; Chang, H. T. Fluorescent gold nanoclusters: Recent advances in sensing and imaging. Anal. Chem. 2015, 87, 216–229.
Shang, L.; Dong, S. J.; Nienhaus, G. U. Ultra-small fluorescent metal nanoclusters: Synthesis and biological applications. Nano Today 2011, 6, 401–418.
Díez, I.; Ras, R. H. A. Fluorescent silver nanoclusters. Nanoscale 2011, 3, 1963–1970.
Lu, Y. Z.; Chen, W. Size effect of silver nanoclusters on their catalytic activity for oxygen electro-reduction. J. Power Sources 2012, 197, 107–110.
Tang, Q.; Hu, G. X.; Fung, V.; Jiang, D. E. Insights into interfaces, stability, electronic properties, and catalytic activities of atomically precise metal nanoclusters from first principles. Acc. Chem. Res. 2018, 51, 2793–2802.
Zheng, K.; Zhang, J. W.; Zhao, D.; Yang, Y.; Li, Z. M.; Li, G. Motif-mediated Au25(SPh)5(PPh3)10X2 nanorods with conjugated electron delocalization. Nano Res. 2019, 12, 501–507.
Wan, X. K.; Yuan, S. F.; Lin, Z. W.; Wang, Q. M. A chiral gold nanocluster Au20 protected by tetradentate phosphine ligands. Angew. Chem., Int. Ed. 2014, 126, 2967–2970.
Santizo, I. E.; Hidalgo, F.; Pérez, L. A.; Noguez, C.; Garzón, I. L. Intrinsic chirality in bare gold nanoclusters: The Au34− case. J. Phys. Chem. C 2008, 112, 17533–17539.
Bonanno, A.; Pérez-Herráez, I.; Zaballos-García, E.; Pérez-Prieto, J. Gold nanoclusters for ratiometric sensing of pH in extremely acidic media. Chem. Commun. 2020, 56, 587–590.
Sun, J.; Jin, Y. D. Fluorescent Au nanoclusters: Recent progress and sensing applications. J. Mater. Chem. C 2014, 2, 8000–8011.
Zhang, L. B.; Wang, E. K. Metal nanoclusters: New fluorescent probes for sensors and bioimaging. Nano Today 2014, 9, 132–157.
Tanaka, S. I.; Miyazaki, J.; Tiwari, D. K.; Jin, T.; Inouye, Y. Fluorescent platinum nanoclusters: Synthesis, purification, characterization, and application to bioimaging. Angew. Chem. 2011, 123, 451–455.
Hasobe, T.; Imahori, H.; Fukuzumi, S.; Kamat, P. V. Light energy conversion using mixed molecular nanoclusters. Porphyrin and C60 cluster films for efficient photocurrent generation. J. Phys. Chem. B 2003, 107, 12105–12112.
Abbas, M. A.; Kamat, P. V.; Bang, J. H. Thiolated gold nanoclusters for light energy conversion. ACS Energy Lett. 2018, 3, 840–854.
Qin, Z. X.; Wang, J. H.; Sharma, S.; Malola, S.; Wu, K. F.; Häkkinen, H.; Li, G. Photo-induced cluster-to-cluster transformation of [Au37- x Ag x (PPh3)13Cl10]3+ into [Au25- y Ag y (PPh3)10Cl8]+: Fragmentation of a trimer of 8-electron superatoms by light. J. Phys. Chem. Lett. 2021, 12, 10920–10926.
Yang, T. Q.; Peng, B.; Shan, B. Q.; Zong, Y. X.; Jiang, J. G.; Wu, P.; Zhang, K. Origin of the photoluminescence of metal nanoclusters: From metal-centered emission to ligand-centered emission. Nanomaterials 2020, 10, 261.
Wu, Z. N.; Yao, Q. F.; Chai, O. J. H.; Ding, N.; Xu, W.; Zang, S. Q.; Xie, J. P. Unraveling the impact of Gold(I)-thiolate motifs on the aggregation-induced emission of gold nanoclusters. Angew. Chem., Int. Ed. 2020, 59, 9934–9939.
Chen, T. K.; Lin, H. B.; Cao, Y. T.; Yao, Q. F.; Xie, J. P. Interactions of metal nanoclusters with light: Fundamentals and applications. Adv. Mater. 2022, 34, 2103918.
Yang, T. Q.; Dai, S.; Tan, H.; Zong, Y. X.; Liu, Y. Y.; Chen, J. Q.; Zhang, K.; Wu, P.; Zhang, S. J.; Xu, J. H. et al. Mechanism of photoluminescence in Ag nanoclusters: Metal-centered emission versus synergistic effect in ligand-centered emission. J. Phys. Chem. C 2019, 123, 18638–18645.
Qin, Z. X.; Hu, S.; Han, W. H.; Li, Z. W.; Xu, W. W.; Zhang, J. J.; Li, G. Tailoring optical and photocatalytic properties by single-Ag-atom exchange in Au13Ag12(PPh3)10Cl8 nanoclusters. Nano Res. 2022, 15, 2971–2976.
Pyo, K.; Thanthirige, V. D.; Kwak, K.; Pandurangan, P.; Ramakrishna, G.; Lee, D. Ultrabright luminescence from gold nanoclusters: Rigidifying the Au(I)-thiolate shell. J. Am. Chem. Soc. 2015, 137, 8244–8250.
Yu, Y.; Luo, Z. T.; Chevrier, D. M.; Leong, D. T.; Zhang, P.; Jiang, D. E.; Xie, J. P. Identification of a highly luminescent Au22(SG)18 nanocluster. J. Am. Chem. Soc. 2014, 136, 1246–1249.
Gan, Z. B.; Lin, Y. J.; Luo, L.; Han, G. M.; Liu, W.; Liu, Z. J.; Yao, C. H.; Weng, L. H.; Liao, L. W.; Chen, J. S. et al. Fluorescent gold nanoclusters with interlocked staples and a fully thiolate-bound kernel. Angew. Chem., Int. Ed. 2016, 55, 11567–11571.
Das, A.; Li, T.; Li, G.; Nobusada, K.; Zeng, C. J.; Rosi, N. L.; Jin, R. C. Crystal structure and electronic properties of a thiolate-protected Au24 nanocluster. Nanoscale 2014, 6, 6458–6462.
Cao, Y. T.; Liu, T. Y.; Chen, T. K.; Zhang, B. H.; Jiang, D. E.; Xie, J. P. Revealing the etching process of water-soluble Au25 nanoclusters at the molecular level. Nat. Commun. 2021, 12, 3212.
Cao, Y. T.; Fung, V.; Yao, Q. F.; Chen, T. K.; Zang, S. Q.; Jiang, D. E.; Xie, J. P. Control of single-ligand chemistry on thiolated Au25 nanoclusters. Nat. Commun. 2020, 11, 5498.
Yao, Q. F.; Chen, T. K.; Yuan, X.; Xie, J. P. Toward total synthesis of thiolate-protected metal nanoclusters. Acc. Chem. Res. 2018, 51, 1338–1348.
Bertorelle, F.; Russier-Antoine, I.; Comby-Zerbino, C.; Chirot, F.; Dugourd, P.; Brevet, P. F.; Antoine, R. Isomeric effect of mercaptobenzoic acids on the synthesis, stability, and optical properties of Au25(MBA)18 nanoclusters. ACS Omega 2018, 3, 15635–15642.
Kang, X.; Chong, H. B.; Zhu, M. Z. Au25(SR)18: The captain of the great nanocluster ship. Nanoscale 2018, 10, 10758–10834.
Yuan, X.; Zhang, B.; Luo, Z. T.; Yao, Q. F.; Leong, D. T.; Yan, N.; Xie, J. P. Balancing the rate of cluster growth and etching for gram-scale synthesis of thiolate-protected Au25 nanoclusters with atomic precision. Angew. Chem., Int. Ed. 2014, 53, 4623–4627.
Chen, T. K.; Yao, Q. F.; Nasaruddin, R. R.; Xie, J. P. Electrospray ionization mass spectrometry: A powerful platform for noble-metal nanocluster analysis. Angew. Chem., Int. Ed. 2019, 58, 11967–11977.
Pei, Y.; Tang, J.; Tang, X. Q.; Huang, Y. Q.; Zeng, X. C. New structure model of Au22(SR)18: Bitetrahederon golden kernel enclosed by [Au6(SR)6] Au(I) complex. J. Phys. Chem. Lett. 2015, 6, 1390–1395.
Han, X. S.; Luan, X. Q.; Su, H. F.; Li, J. J.; Yuan, S. F.; Lei, Z.; Pei, Y.; Wang, Q. M. Structure determination of alkynyl-protected gold nanocluster Au22(tBuC≡C)18 and its thermochromic luminescence. Angew. Chem., Int. Ed. 2020, 59, 2309–2312.