M13 Clusters Research Articles

Understanding the atomistic behavior of small molecules (O2 and N2) on monometallic M13 nanoparticles

Both experimental data and density functional theory (DFT) calculations clearly indicate that the reactivity of metal clusters for NO is determined by the energy and orbital type (4d or 5s) of the valence band top. Here, we explore this correlation for the reactivity of M13 nanoclusters, being M = Ag, Au, Co, Cu, Fe, Ir, Ni, Os, Pd, Pt, Rh and Ru and adsorbed diatomic molecules, O2 or N2. The possible adsorption configurations, interatomic distances, and adsorption energies for O2 and N2 on M13 clusters have been analyzed in detail.

High‐Spin and Reactive Fe13 Cluster with Exposed Metal Sites

AbstractAtomically defined large metal clusters have applications in new reaction development and preparation of materials with tailored properties. Expanding the synthetic toolbox for reactive high nuclearity metal complexes, we report a new class of Fe clusters, Tp*4W4Fe13S12, displaying a Fe13 core with M−M bonds that has precedent only in main group and late metal chemistry. M13 clusters with closed shell electron configurations can show significant stability and have been classified as superatoms. In contrast, Tp*4W4Fe13S12 displays a large spin ground state of S=13. This compound performs small molecule activations involving the transfer of up to 12 electrons resulting in significant cluster rearrangements.

High-Spin and Reactive Fe13 Cluster with Exposed Metal Sites.

Atomically defined large metal clusters have applications in new reaction development and preparation of materials with tailored properties. Expanding the synthetic toolbox for reactive high nuclearity metal complexes, we report a new class of Fe clusters, Tp*4 W4 Fe13 S12 , displaying a Fe13 core with M-M bonds that has precedent only in main group and late metal chemistry. M13 clusters with closed shell electron configurations can show significant stability and have been classified as superatoms. In contrast, Tp*4 W4 Fe13 S12 displays a large spin ground state of S=13. This compound performs small molecule activations involving the transfer of up to 12 electrons resulting in significant cluster rearrangements.

Cover Feature: Synergistic Effects in the Activity of Nano‐Transition‐Metal Clusters Pt12M (M=Ir, Ru or Rh) for NO Dissociation (ChemPhysChem 21/2022)

The Cover Feature shows NO molecules adsorbed on four different M13 clusters prior and after NO dissociation. Doping Pt13 with Ru, Rh or Ir stabilizes NO adsorption and lowers activation energies of the DeNOx process, pictorially represented by mountainous terrain surrounding the process. Cover design by Dr. Jelle Vekeman. More information can be found in the Research Article by Jelle Vekeman, Frederik Tielens and co-workers.

Synergistic Effects in the Activity of Nano-Transition-Metal Clusters Pt12 M (M=Ir, Ru or Rh) for NO Dissociation.

The dissociation of environmentally hazardous NO through dissociative adsorption on metallic clusters supported by oxides, is receiving growing attention. Building on previous research on monometallic M13 clusters [The Journal of Physical Chemistry C 2019, 123 (33), 20314-20318], this work considers bimetallic Pt12 M (M=Rh, Ru or Ir) clusters. The adsorption energy and activation energy of NO dissociation on the clusters have been calculated in vacuum using Kohn-Sham DFT, while their trends were rationalized using reactivity indices such as molecular electrostatic potential and global Fermi softness. The results show that doping of the Pt clusters lowered the adsorption energy as well as the activation energy for NO dissociation. Furthermore, reactivity indices were calculated as a first estimate of the performance of the clusters in realistic amorphous silica pores (MCM-41) through ab initio molecular dynamics simulations.

Understanding the interaction between carboxylates and coinage metals from first principles.

Carboxylate groups have recently been explored as a new type of ligand to protect superatomic copper and silver nanoclusters, but little is known of the interfacial structure and bonding. Here, we employ density functional theory to investigate the interfaces of a model carboxylate group, CH3COO, on the coinage metal surfaces and clusters. We found that μ2-CH3COO is the most preferred binding mode on the three M(111) surfaces (M = Cu, Ag, and Au), while μ3-CH3COO is also stable on Cu(111) and Ag(111). The saturation coverage was found to be about seven CH3COO groups per nm2 for all surfaces. CH3COO has the strongest binding on Cu and weakest on Au. Moving from the flat surfaces to the icosahedral M13 clusters, we found that the eight-electron superatomic [M13(CH3COO)6]- nanoclusters also prefer the μ2-CH3COO mode on the surface. The icosahedral kernel in [Cu13(CH3COO)6]- and [Ag13(CH3COO)6]- was well maintained after geometry optimization, but a larger deformation was found in [Au13(CH3COO)6]-. Given the broad availability and variety of carboxylic acids including amino acids, our work suggests that carboxylate groups could be the next-generation ligands to further expand the universe of atomically precise metal clusters, especially for Cu and Ag.

Adsorption and dissociation of CO on metal clusters

Adsorption and dissociation of carbon monoxide on metal clusters M13 (M = Ag, Co, Cu, Fe, Ni and Ru), has been studied. Structure stabilities of metal clusters, adsorption sites, adsorption energies and the activation energies for the dissociation of CO were determined using density functional theory. Cohesive and binding energies of metal atoms in M13 clusters of studied metals were calculated, showing the different strength interaction of metal atoms in each particle. Three active adsorption sites on the M13 particles studied have been identified, showing that CO adsorption with covalent nature can occur on different sites depending of the metal cluster. Charge density difference in the M13-CO interaction on all the adsorption sites of all metal clusters showed a strong accumulation of charge density in the MC bonding. Of the group of metal cluster modeled, Ru13, Cu13 and Co13 present higher adsorption energies. On the other hand, Fe13, Co13 and Ru13 present lower activation energies. In all cases, endothermic behavior of CO dissociation was observed. The initial stages of CO interaction with several metal clusters, in comparison with metal surfaces, is presented.

An all-electron density functional theory study of the structure and properties of the neutral and singly charged M12 and M13 clusters: M = Sc–Zn

The electronic and geometrical structures of the M12 and M13 clusters where M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn along with their singly negatively and positively charged ions are studied using all-electron density functional theory within the generalized gradient approximation. The geometries corresponding to the lowest total energy states of singly and negatively charged ions of V13, Mn12, Co12, Ni13, Cu13, Zn12, and Zn13 are found to be different from the geometries of the corresponding neutral parents. The computed ionization energies of the neutrals, vertical electron detachment energies from the anions, and energies required to remove a single atom from the M13 and M13(+) clusters are in good agreement with experiment. The change in a total spin magnetic moment of the cation or anion with respect to a total spin magnetic moment of the corresponding neutral is consistent with the one-electron model in most cases, i.e., they differ by ±1.0 μ(B). Exceptions are found only for Sc12(-), Ti12(+), Mn12(-), Mn12(+), Fe12(-), Fe13(+), and Co12(+).

A Computational Study of the Adsorption of Small Ag and Au Nanoclusters on Graphite

The adsorption of silver and gold atoms, and M2, M6, and M13 (M=Ag or Au) clusters on the (0001) graphite surface has been investigated computationally using the density functional theory (DFT) with periodic boundary conditions and plane wave basis functions. The surface has been modeled as a single carbon sheet. The role of dispersion forces has been studied with an empirical classical model. The results show that the clusters avoid hollow sites on the graphite surface, and that the metal atoms favor atop and bond sites. Large structural changes are observed in octahedral M6 and icosahedral M13 clusters on the graphite surface when compared with gas-phase geometries. The results also indicate that if accurate results are required, the dispersion forces between metal and carbon atoms should be included in the studied systems.

Metal clusters as giant atoms

M12X-type metal clusters of icosahedral symmetry are discussed in terms of the giant atom concept on the basis of the electronic shell structures in free-electron-like metal clusters. The first-principles calculations for Au12,13, Ag12,13, Al12,13, Au12Cr, and Al12Si clusters have been done by the self-consistent local density functional scheme using the norm-conserving pseudopotential in the linear combination of atomic orbitals method. Electronic shell structures in icosahedral clusters are formed by 6s, 5s and 3p orbitals or peripheral atoms in Au, Ag, and Al clusters, respectively. By doping Cr into Au12 and Si into Al12 clusters M13 clusters are stabilized by about 0.7 eV atom-1 (Au12Cr) and 0.2 eV atom-1 (Al12Si) because of the closed shell formation. Interactions between clusters, cluster and surface, and cluster and metal tip used in the atomic force microscope are discussed based on the Harris functional scheme. Dimers of Au12Cr and Al12Si are weakly bound, and the Au13 cluster on Si(111) has two kinds of binding, but Al13 does not. The repulsive or attractive nature of the force between the cluster and Pt tip is considerably dependent on the cluster-tip distance.

ChemInform Abstract: Large Transition‐Metal Clusters. Part 5. Novel Modifications of Gold, Rhodium, and Ruthenium. M13 Clusters as Building Blocks of “Superclusters”.

AbstractThe ligand‐stabilized M55 clusters in complexes such as (I)‐(III) can be smoothly degraded on Pt electrodes in CH2Cl2 solution applying a 20 V d.c.

Cover Picture (Angew. Chem. Int. Ed. Engl. 10/1986)

Angewandte Chemie International Edition in EnglishVolume 25, Issue 10 Cover PictureFree Access Cover Picture (Angew. Chem. Int. Ed. Engl. 10/1986) First published: October 1986 https://doi.org/10.1002/anie.198608531Citations: 2AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Abstract The cover shows a model for the structure of novel gold, rhodium, and ruthernium modifications: 13 metal atoms form a cluster; 13 clusters assemble to form the “supercluster” (M13)13; finally, n superclusters come together to form microcrystallites. These clusters were not discovered by chance, but in an investigation into the existence of small closed-shell clusters lacking protecting peripheral ligands. M55 clusters with ligands may be degraded electrochemically to naked M13 clusters; the species (M13)13 and [(M13)13]n were then identified by means of their Debye-Scherrer diffraction patterns. Further details are reported by G. Schmid et al. on p. 922. Citing Literature Volume25, Issue10October 1986 RelatedInformation

CARBON AND NITROGEN ABUNDANCES IN EXTREMELY METAL-DEFICIENT RED GIANTS.

ABSTRACT The relative carbon and nitrogen abundances of a sample of metal-poor halo giants are analyzed with respect to their similarity with the abundances of similar stars in globular clusters. Spectra of 64 giants selected from the objective prism survey of Bond (1980) were obtained at a resolution of 8 A in the spectral region 3100-5300 A. C/Fe and N/Fe abundance ratios were estimated from the spectra by the method of spectrum synthesis using metallicities estimated from H and K line strengths. Halo giants with metallicities greater than or equal to -2.0, which are characteristic of giants in the M3 and M13 clusters, are found to have C/Fe and N/Fe abundance distributions similar to those of M3 but not M13, for which a greater carbon depletion and nitrogen enhancement is observed. Halo giants with metallicities less than -2.0 showed less carbon depletion and nitrogen enhancement than the corresponding M29 stars. Globular cluster and field halo stars with the same metallicities thus do not appear to be derived from the same parent population.