Structure &amp; bonding of the gold-subhalide cluster I-Au144Cl60[z]

Tlahuice‐Flores, Alfredo; Black, David M.; Bach, Stephan B. H.; José–Yacamán, Miguel; Whetten, Robert L.

doi:10.1039/c3cp53902d

Cited by 45 publications

(101 citation statements)

References 31 publications

(60 reference statements)

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“…This ring representation and the M@M 12 (M 2 (SR) 3 ) 6 model are valid for both Au 25 (SR) 18 and Ag 25 (SR) 18 , and in general for their arbitrary mixed-metal compositions, Ag m Au n (SR) 18 , as is evident from their crystallographic data222853. In this structural viewpoint, the stability of the inherent structure may be attributed to the interlocked rings5056 and its stiff framework39. Hence, such a stable structural configuration would remain intact while atomic units are substituted, involving geometrical distortions and opening and reclosing of parts of the ring structure.…”

Section: Discussionmentioning

confidence: 56%

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Structure-conserving spontaneous transformations between nanoparticles

Krishnadas¹,

Baksi²,

Ghosh³

et al. 2016

Nat Commun

114

186

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Ambient, structure- and topology-preserving chemical reactions between two archetypal nanoparticles, Ag25(SR)18 and Au25(SR)18, are presented. Despite their geometric robustness and electronic stability, reactions between them in solution produce alloys, AgmAun(SR)18 (m+n=25), keeping their M25(SR)18 composition, structure and topology intact. We demonstrate that a mixture of Ag25(SR)18 and Au25(SR)18 can be transformed to any arbitrary alloy composition, AgmAun(SR)18 (n=1–24), merely by controlling the reactant compositions. We capture one of the earliest events of the process, namely the formation of the dianionic adduct, (Ag25Au25(SR)36)2−, by electrospray ionization mass spectrometry. Molecular docking simulations and density functional theory (DFT) calculations also suggest that metal atom exchanges occur through the formation of an adduct between the two clusters. DFT calculations further confirm that metal atom exchanges are thermodynamically feasible. Such isomorphous transformations between nanoparticles imply that microscopic pieces of matter can be transformed completely to chemically different entities, preserving their structures, at least in the nanometric regime.

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Section: Discussionmentioning

confidence: 56%

“…In this model, these clusters can be represented as M@(M 8 (SR) 6 ) 3 where the central atom M is considered to be surrounded by three, interlocked M 8 (SR) 6 Borromean rings5056 (see the path traced by the thick, red bonds in Fig. 5d).…”

Section: Discussionmentioning

confidence: 99%

Structure-conserving spontaneous transformations between nanoparticles

Krishnadas¹,

Baksi²,

Ghosh³

et al. 2016

Nat Commun

114

186

View full text Add to dashboard Cite

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“…The atomic structure of the inorganic core, including the sulfur-gold bonding, was taken from Refs. 59–61. System I consists of two GS-AuNPs; System II, two PhS-AuNPs; System III; two CyS-AuNPs; System IV, two p- APhS-AuNPs; System V, one GS-AuNP and one p- APhS-AuNP.…”

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confidence: 99%

Interaction between functionalized gold nanoparticles in physiological saline

Alsharif

Chen

Tlahuice‐Flores

et al. 2014

Phys. Chem. Chem. Phys.

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Interactions between functionalized noble-metal particles in aqueous solution are central to applications relying on controlled equilibrium association. Herein we obtain the potentials of mean force (PMF) for pair-interactions between functionalized gold nanoparticles (AuNPs) in physiological saline, based upon > 1000-ns experiments in silico of all-atom model systems under equilibrium and nonequilibrium conditions. Four types of functionalization are built by coating the globular Au144 cluster each with 60 thiolate groups: GS-AuNP (glutathionate), PhS-AuNP (thiophenol), CyS-AuNP (cysteinyl), and p-APhS-AuNP (para-aminothiophenol), which are, respectively, negatively charged, hydrophobic (neutral-nonpolar), hydrophilic (neutral-polar), and positively charged at neutral pH. The results confirm the behaviour expected of neutral (hydrophilic or hydrophobic) particles in dilute aqueous environment, but the PMF curves demonstrate that the charged AuNPs interact with one another in a unique way — mediated by H2O molecules and electrolyte (Na+,Cl−) — in a physiological environment. In the case of two GS-AuNPs, the excess, neutralizing Na+ ions form a mobile (or ‘dynamic’) cloud of enhanced concentration between like-charged GS-AuNPs, inducing a moderate attraction (~ 25-kT) between them. And, to a lesser degree, for a pair of p-APhS-AuNPs, the excess, neutralizing Cl− ions (less mobile than Na+) also form a cloud of higher concentration between the two like-charged p-APhS-AuNPs, inducing weaker yet significant attractions (~ 12-kT). In the combination of one GS- and one p-APhS-AuNP, the direct, attractive Coulombic force is completely screened out while the solvation effects give rise to moderate repulsion between the two unlike-charged AuNPs.

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“…Figure 2) for the maximum charge state detected during ESI-MS measurements of the thiolated Au 144 cluster. 15 Briefly, we have relaxed a set of initial structural isomers by imposing a 0.01 eV/Å value in force, using the PBE approximation for the Figure S1. The two features are assigned z = 1+ and 2+ charge states.…”

Section: ■ Experimental Methodsmentioning

confidence: 99%

ESI-MS Identification of Abundant Copper–Gold Clusters Exhibiting High Plasmonic Character

Bhattarai¹,

Black²,

Boppidi³

et al. 2015

J. Phys. Chem. C

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The protected noble-metal structures comprising 145 metal-atom sites and 60 ligands are among the frequently identified larger metal-cluster systems exploited in many avenues of research. Herein we report a comparative electrospray ionizationmass spectrometry (ESI-MS) investigation of the 60-fold thiolated Au 144 and CuAu 144 clusters, in various positive charge-states, in conjunction with a density-functional theoretical (DFT) analysis based upon the icosahedral Pd 145 -structure-type applicable to these systems. Samples rich in the hexanethiolate-protected CuAu 144 clusters are obtained via a single-phase reduction process. The predicted electronic structure of the vacancy-centered Au 144 (SR) 60 system provided a simple rationale for the limiting [4+] charge-state observed of Au 144 , whereas the maximal [3+] charge detected on the CuAu 144 (SR) 60 cluster can be explained if the 145th atom occupies the central site. Occupancy of the center-site stabilizes the superatomic 3S-orbital, and thereby shifts the shell-closing count from 82 to 84 free electrons. The DFT-calculated energetics also predicts a strong (0.65 eV) preference for placing the smaller Cu ion in this central site. Remarkably, the optical absorption spectra of dilute tetrahydrofuran (THF) solutions feature a broad band centered near 2.3 eV, in contrast to the previously reported "nonplasmonic" response of sub-2.0-nm all-gold or -copper clusters. Other methods (matrix-assisted laser desorption ionization mass spectrometry and high-resolution electron microscopy) were used to investigate whether aggregation phenomena might account for this observed plasmon emergence. This unusual result points to the need to obtain highly purified samples of copper-doped gold clusters of ca. 145 atoms total. ■ INTRODUCTIONIn the physical chemistry of metal clusters, one prime concern has been to elucidate the rules, or criteria, that can explain the selection of exceptionally stable cluster sizes, or compositional "magic numbers", and predict the existence of other related special clusters. Typically, such special clusters are first identified by mass-spectrometric analysis, well before definitive structural characterization can be achieved. In the simpler ligand-free metal clusters, the main rules select for (i) the number of free electrons, n e , available to fill the set of angularmomentum shells, according to the universal aufbau of the spherical electron-shell model (or superatom analogy); and (ii) the number of metal atoms, n, required to complete concentric shells of atomic sites, as relating to crystallography and surface structure. 1,2 A simple metal cluster of formula A n[z] is said to be "doubly magic", if both counts, n and n e = v A n − z, satisfy the respective shell-closing criteria, where v A represents the metalatom valence and ze is the electrical charge. 3 Selected monolayer-protected clusters (MPCs), 4 denoted compositionally by A n X p [z] , feature an additional, external shell of p anionic ligand-groups, X − , that coordinate specifically t...

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Structure & bonding of the gold-subhalide cluster I-Au144Cl60[z]

Cited by 45 publications

References 31 publications

Structure-conserving spontaneous transformations between nanoparticles

Structure-conserving spontaneous transformations between nanoparticles

Interaction between functionalized gold nanoparticles in physiological saline

ESI-MS Identification of Abundant Copper–Gold Clusters Exhibiting High Plasmonic Character

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