Kinetics of Intercluster Reactions between Atomically Precise Noble Metal Clusters [Ag₂₅(DMBT)₁₈]⁻ and [Au₂₅(PET)₁₈]⁻ in Room Temperature Solutions

Abstract

The kinetics of intercluster metal atom exchange reactions between solvated [Ag 25 (DMBT) 18 ] − and [Au 25 (PET) 18 ] − (DMBT and PET are 2,4dimethylbenzenethiol and 2-phenylethanethiol, respectively, both C 8 H 10 S) were probed by electrospray ionization mass spectrometry and computer-based modeling. Anion mass spectra and collision induced dissociation (CID) measurements show that both cluster monomers and dimers are involved in the reactions. We have modeled the corresponding kinetics assuming a reaction mechanism in which metal atom exchange occurs through transient dimers. Our kinetic model contains three types of generic reactions: dimerization of monomers, metal atom exchange in the transient dimers, and dissociation of the dimers to monomers. There are correspondingly 377 discrete species connected by in total 1302 reactions (i.e., dimerization, dissociation and atom exchange reactions) leading to the entire series of monomeric and dimeric products [Ag m Au 25−m ] − (m = 1−24) and [Ag m Au 50−m ] 2− (m = 0−50), respectively.The rate constants of the corresponding reactions were fitted to the experimental data, and good agreement was obtained with exchange rate constants which scale with the probability of finding a silver or gold atom in the respective monomeric subunit of the dimer, i.e., reflecting an entropic driving force for alloying. Allowing the dimerization rate constant to scale with increasing gold composition of the respective reactants improves the agreement further. The rate constants obtained are physically plausible, thus strongly supporting dimer-mediated metal atom exchange in this intercluster reaction system.

Regulation of Surface Structure of [Au9Ag12(SAdm)4(Dppm)6Cl6](SbF6)3 Nanocluster via Alloying

“…671nm = 0.3 for Au 9 Ag 12 and Abs. 712nm = 0.3 for Au 9 Ag 8 Cu 4 , respectively) are performed ( Zhang et al, 2016 ; Khatun et al, 2020 ; Neumaier at al., 2021 ). As shown in Figure 7 , the reaction was completed quickly (1 min), similar to the UV-vis spectrum that prolongs the reaction for 3 h. As shown in the Figures 7A,B , intercluster reactions produce a spectrum with 428, 482 and 702 nm, respectively.…”

Carboranethiol-Protected Propeller-Shaped Photoresponsive Silver Nanomolecule

“…Ligand-exchange-induced structural conversion was also noticed for a few silver nanoclusters . Atomic exchange between two nanoclusters in solution leads to a mixture of alloy nanoclusters through the formation of transient dimer species, following a concerted reaction pathway. , The use of a suitable surface ligand determines the stability of the nanoclusters. Among different thiols, carboranethiols are gaining prominence because of their extraordinary thermal stability, robust 3D structure, and specific borane aromaticity with electron delocalization all over the icosahedral boron–carbon framework .…”

Assembling Atomically Precise Noble Metal Nanoclusters Using Supramolecular Interactions

“…Alloying of NMNCs can be achieved easily via intercluster reactions. − Reaction between two well-known NMNCs, [Ag 44 (SR 1 ) 30 ] 4– and [Au 25 (SR) 18 ] − (where SR 1 and SR 2 were 4-fluorothiophenol and 2-phenylethanethiol, respectively), led to the alloy NMNCs [Ag y Au 44– y (SR 1 ) 30– n (SR 2 ) n ] and [Au x Ag 25– x (SR 2 ) 18– m (SR 1 ) m ] . Another example is the intercluster reaction between [Ag 25 (DMBT) 18 ] − and [Au 25 (PET) 18 ] − , and alloying of NMNCs occurred keeping their [M 25 (SR) 18 ] − structure and topology intact, via the dianionic adduct, [Au 25 Ag 25 (PET) 18 (DMBT) 18 ] 2– (Figure Aa and b) .…”