Isomerization in Alkynyl-Protected Gold Nanoclusters

Abstract

We report the controlled synthesis and structures of two isomeric gold nanoclusters, whose compositions are determined to be Au 23 (CCBu t ) 15 (denoted as Au 23 -1 and Au 23 -2) by single-crystal X-ray diffraction and matrixassisted laser desorption ionization time-of-flight mass spectrometry. This is the first time isomerism is discovered in alkynyl-protected gold nanoclusters. The metal-toligand ratios in these two clusters are different from known Au n (SR) m systems and have not been observed in the Au x (CCPh) y family. This pair of isomers exhibits different optical properties, although they have similar structures and identical components. For both Au 23 clusters, time-dependent density functional theory calculations revealed the frontier orbitals highest occupied molecular orbital (HOMO)−1, HOMO, and lowest unoccupied molecular orbital (LUMO) are mainly constructed from the Au 15 kernel and V-shaped alkynyl−gold motifs. The HOMO → LUMO transition of Au 23 -1 is optically forbidden, whereas it is allowed in Au 23 -2. It is also found that Au 23 -2 cluster can be transformed to Au 23 -1 spontaneously under ambient conditions. This work offers further insight into the synthesis and isomerism of all-alkynyl-protected gold nanoclusters and will stimulate more investigation of isomeric metal 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.…”

Molecular reactivity of thiolate-protected noble metal nanoclusters: synthesis, self-assembly, and applications

“…In addition to thiolates, many other organic ligands have been exploited to synthesize atomically precise metal NCs, due to their diverse binding modes and binding strength with metal centres. Such organic ligands of current interest include phosphines, [258][259][260] hydrides, [261][262][263][264] alkynyls, [265][266][267][268] N-heterocyclic carbenes, [269][270][271] carboxylates, 219,272,273 and solvent molecules. 219,[272][273][274][275] In particular, recent ndings have shown that organic ligands with relatively low binding affinity to Ag (e.g., CF 3 COO À and CH 3 CN) can be replaced by bridging ligands (e.g., 4,4 0 -bypyridine), further cross-linking mixed-ligand-protected Ag NCs into a 3D network reminiscent of MOF structures.…”

Luminescence Regulation of Silver‐Thiolate Clusters Protected by 1,2‐Dithiolate‐o‐carborane

“…In recent years, monolayer‐protected metal nanoclusters (NCs) have gradually gained much attention because of not only their atomically precise aesthetical structures, [ 1 ] but also their wide variety of applications, such as luminescence, [ 2 ] chirality, [ 3 ] cell imaging, [4] catalysis, [5] and electrochemistry. [6] Particularly, photoluminescence (PL) is one of the most explored functions.…”