Polymorphism of Phosphine-Protected Gold Nanoclusters: Synthesis and Characterization of a New 22-Gold-Atom Cluster

Abstract

A new Au22 nanocluster, protected by bis(2-diphenyl-phosphino)ethyl ether (dppee or C28 H28 OP2 ) ligand, has been synthsized and purified with high yield. Electrospray mass spectrometry shows that the new cluster has a formula of Au22 (dppee)7 , containing 22 gold atoms and seven dppee ligands. The cluster is found to be stable as a solid, but metastable in solution. The new cluster has been characterized by UV-Vis-NIR absorption spectroscopy, collision-induced dissociation, and (31) P-NMR. The properties of the new cluster have been compared with the previous Au22 (dppo)6 nanocluster (dppo = 1,8-bis(diphenyl-phosphino)octane or C32 H36 P2 ), which contains two fused Au11 units. All the experimental data indicate that the new Au22 (dppee)7 cluster is different from the previously known Au22 (dppo)6 cluster and represents a new Au22 core, which contains most likely one Au11 motif with several Au2 (dppee) or Au(dppee) units. The Au22 (dppee)7 cluster provides a new example of the ligand effects on the nuclearity and structural polymorphism of phosphine-protected atom-precise gold nanoclusters.

Halogen effects on the electronic and optical properties of Au13nanoclusters

“…11,12 With the availability of single crystal X-ray structures, 13,14 extensive attention has been paid to the role of ligands in the syntheses and photophysical properties of gold nanoclusters with different nuclearities. 15,16 To obtain novel gold clusters with different photophysical properties, organic ligands such as thiols, phosphines and alkynes have been widely exploited in the syntheses of gold nanoclusters (Au n ) such as Au 8 , 17,18 Au 9 , 19 Au 11 , 20,21 Au 13 , [22][23][24][25][26][27] Au 18 , 27,28 Au 20 , 29,30 Au 22 , 31,32 Au 23 , 33 Au 24 , 34 Au 25 , 35,36 Au 32 , 37 Au 37 , 38 Au 44 , 39 Au 52 , 40 Au 55 , 41 and Au 102 . 13 Among all of the gold nanoclusters that have been structurally characterized, icosahedral Au 13 nanoclusters have been more extensively studied due to their highly symmetrical structure and prominent photoluminescence properties.…”

Understanding the Chemical Insights of Staple Motifs of Thiolate‐Protected Gold Nanoclusters

“…[ 2–6 ] Now, AuNCs have been recognized as a kind of promising nanomaterials owning to their spectroscopic properties, biological applications, catalytic properties, and etc. [ 7–13 ]…”

[Ag15H13(DPPH)5]2+ and [Ag27H22(DPPB)7]3+: Two New Hydride and Phosphine Co-Protected Clusters and Their Fragmentation Leading to Naked Clusters, Ag13+ and Ag25+

“…Staple units are formed by the interaction of sulfur of the thiol commonly used as the ligand and the surface metal atoms, but this is not a general case and examples include phosphine-protected systems. , The properties of nanoclusters can be manipulated either by changing the core or the ligand surface, which will in turn alter their total structure. , Therefore, the introduction of new ligand results in a new cluster system, which can be a promising synthetic approach for a new class of materials. Liquid phase synthesis of noble metal nanoclusters has been investigated widely with classic ligands, namely thiols, , phosphines, , alkynyls and/or their combinations . The use of these organic ligands results in a wide range of nuclearities in nanoclusters which have been characterized as Au 102 , Au 25 , Au 18 , Ag 44 , Ag 25 , Ag 29 , etc., by varying ligands and synthetic methods.…”