Elucidating ligand effects in thiolate-protected metal clusters using Au₂₄Pt(TBBT)₁₈ as a model cluster

Abstract

2-Phenylethanethiolate (PET) and 4-tert-butylbenzenethiolate (TBBT) are the most frequently used ligands in the study of thiolate (SR)-protected metal clusters. However, the effect of difference in the functional group between these ligands on the fundamental properties of the clusters has not been clarified. We synthesized [Au 24 Pt(TBBT) 18 ] 0 , which has the same number of metal atoms, number of ligands, and framework structure as [Au 24 Pt(PET) 18 ] 0 , by replacing ligands of [Au 24 Pt(PET) 18 ] 0 with TBBT. It was found that this ligand exchange is reversible unlike the case of other metal-core clusters. A comparison of the geometrical/electronic structure and stability of the clusters between [Au 24 Pt(PET) 18 ] 0 and [Au 24 Pt(TBBT) 18 ] 0 revealed three things with regard to the effect of ligand change from PET to TBBT on [Au 24 Pt(SR) 18 ] 0 : (1) the induction of metal-core contraction and Au-S bond elongation, (2) no substantial effect on the HOMO-LUMO gap but a clear difference in optical absorption in the visible region, and (3) the decrease of stabilities against degradation in solution and under laser irradiation. By using these two clusters as model clusters, it is expected that the effects of the structural difference of ligand functionalgroups on the physical properties and functions of clusters, such as catalytic ability and photoluminescence, would be clarified. † Electronic supplementary information (ESI) available: Bond lengths, peak positions in SWV curves, additional schemes, characterization of a precursor, photograph of TLC and crystal, ESI mass and XPS spectra, HPLC chromatogram, crystal data of the product. CCDC 1944945. For ESI and crystallographic data in CIF or other electronic format see

Dynamics of Pd Dopant Atoms inside Au Nanoclusters during Catalytic CO Oxidation

“…Pure oxidation or reduction improved activity at 250 °C, but the maximum and lower temperature activity was obtained by a combination of oxidation and reduction (pretO 2 –H 2 ). Oxidation allows for removal of ligands 49 , 74 and surface impurities (synthesis residues), while the subsequent H 2 treatment reduces oxidized Pd (and Au) atoms. 61 Activity set in at 225 °C, which agrees with CO oxidation on (impregnated) Pd/Al 2 O 3 catalysts (below 225 °C, the actives sites are poisoned by CO).…”

Atomically Precise Alloy Nanoclusters

“…The chemical compositiono ft he product strongly depends on the chemical properties of thiolate. [49,83] Thus, the thiolates in the same category (Scheme 1A-D) are typicallyu sed for obtaining the alloy NCs with the same numbers of metal atoms and ligands. In the following subsections, four representative synthesis methods of alloy NCs are outlined.…”

“…[30][31][32][33][34][35][36][37][38][39]41] Similar researchh as recently been undertaken by several groups,a nd their findings have demonstrated that the mixing( alloying) of heteroelements is an extremelye ffective means to modulate the electronic structure and functions of NCs. [66][67][68][69][70][71][72][73][74][75][76][77][78][79][80][81][82][83] In addition,…”

“…The number of publications on these NCs has increased explosively in recent years [2] . Such studies have provided much insight into the effects of alloying on the electronic structure and function of NCs [66–83] . However, it is difficult for researchers, especially those unfamiliar to the field, to follow all of this research because the knowledge is increasing so rapidly.…”

One-, Two-, and Three-Dimensional Self-Assembly of Atomically Precise Metal Nanoclusters

“…Therefore, if the number of constituent atoms of metal NCs is controlled, it is possible to produce various physical/chemical properties and functions by using only one type of metal element. If several types of elements can be used, it becomes possible to obtain more functionalities [ 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 ]. For these reasons, metal NCs have been attracting considerable attention as a central material in nanotechnology.…”