Controlling Gold Nanoclusters by Diphospine Ligands

Abstract

We report the synthesis and structure determination of a new Au22 nanocluster coordinated by six bidentate diphosphine ligands: 1,8-bis(diphenylphosphino) octane (L(8) for short). Single crystal X-ray crystallography and electrospray ionization mass spectrometry show that the cluster assembly is neutral and can be formulated as Au22(L(8))6. The Au22 core consists of two Au11 units clipped together by four L(8) ligands, while the additional two ligands coordinate to each Au11 unit in a bidentate fashion. Eight gold atoms at the interface of the two Au11 units are not coordinated by any ligands. Four short gold-gold distances (2.64-2.65 Å) are observed at the interface of the two Au11 clusters as a result of the clamping force of the four clipping ligands and strong electronic interactions. The eight uncoordinated surface gold atoms in the Au22(L(8))6 nanocluster are unprecedented in atom-precise gold nanoparticles and can be considered as potential in situ active sites for catalysis.

Phosphine-Coordinated Pure-Gold Clusters: Diverse Geometrical Structures and Unique Optical Properties/Responses

“…For example, he above Au(PPh 3 )Cl / tBuNH 2 ·BH 3 system coupled with C5-(dpppe, Ph 2 P(CH 2 ) 5 PPh 2 ) or C6-bridged (dpph, Ph 2 P(CH 2 ) 6 6 (37, Scheme 1g) [73]. We have also shown that the use of C2-bridged diphosphine (dppp) for the NaBH 4 reduction of chlorogold(I) complex in ethanol results in the formation of a Au 11 species, which however accommodate a different number of coordinating phosphine ligands (Au 11 L 12 type) (e) [74].…”

“…The spectra of higher-nuclearity centered clusters (36)(37)(38)(39) taken from the literatures [66,73,79,85] are summarized in Fig. 6b.…”

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

“…[ 27 ] It is interesting to note that many of these AuNCs, such as Au 6 , [34][35][36] Au 7 , [ 37,38 ] Au 8 , [ 39,40 ] Au 9 , [ 41,42 ] Au 10 , [ 43,44 ] and Au 11 , [45][46][47] have at least two different core geometries when different phosphine ligands are used. However, beyond Au 13 , only four different phosphine-protected AuNCs have been structurally characterized by X-ray crystallography, including Au 14 , [ 48 ] Au 20 , [49][50][51] Au 22 , [ 52 ] and Au 39 . [ 53 ] It should be pointed out that two different Au 20 core structures have been reported using different ligands.…”

“…[ 59 ] Using the 1,8-bis(diphenyl-phosphino) octane (dppo for short), we have synthesized a Au 22 (dppo) 6 cluster with a relatively high yield. [ 52 ] Structural determination using single crystal X-ray diffraction revealed that the Au 22 core in Au 22 (dppo) 6 contained two fused Au 11 units. Interestingly, there are eight Au atoms at the interface of the two Au 11 units that were not coordinated by the dppo ligands.…”

“…Here we report the synthesis of a new Au 22 cluster using the bis(2-diphenyl-phosphino)ethyl ether (dppee or C 28 H 28 OP 2 ) ligand, which has a slightly shorter chain length than the dppo ligand [ 52 ] and can be viewed as replacing four CH 2 groups in dppo by an ether group. The new Au 22 cluster is found to be coordinated by seven dppee ligands, Au 22 (dppee) 7 , and can be obtained with relatively high yield and purity.…”