Antimony Clusters Research Articles

Lattice distortion enhanced self-trapped excitons emission in antimony halide crystalline clusters

Lattice distortion enhanced self-trapped excitons emission in antimony halide crystalline clusters

Structural Evolution and Properties of Praseodymium Antimony Oxochlorides Based on a Chain-like Tertiary Building Unit

Unveiling the structural evolution of single-crystalline compounds based on certain building units may help greatly in guiding the design of complex structures. Herein, a series of praseodymium antimony oxohalide crystals have been isolated under solvothermal conditions via adjusting the solvents used, that is, [HN(CH2CH3)3][FeII(2,2'-bpy)3][Pr4Sb12O18Cl15]·EtOH (1) (2,2'-bpy = 2,2'-bipyridine), [HN(CH2CH3)3][FeII(2,2'-bpy)3]2[Pr4Sb12O18Cl14)2Cl]·N(CH2CH3)3·2H2O (2), and (H3O)[Pr4Sb12O18Cl12.5(TEOA)0.5]·2.5EtOH (3) (TEOA = mono-deprotonated triethanolamine anion). Single-crystal X-ray diffraction analysis revealed that all the three structures feature an anionic zig-zag chain of [Pr4Sb12O18Cl15-x]n as the tertiary building unit (TBU), which is formed by interconnections of praseodymium antimony oxochloride clusters (denoted as {Pr4Sb12}) as secondary building units. Interestingly, different arrangements or linkages of chain-like TBUs result in one-dimensional, two-dimensional layered, and three-dimensional structures of 1, 2, and 3, respectively, thus demonstrating clearly the structural evolution of metal oxohalide crystals. The title compounds have been characterized by elemental analysis, powder X-ray diffraction, thermogravimetric analysis, and UV-Vis spectroscopy, and the photodegradation for methyl blue in an aqueous solution of compound 1 has been preliminarily studied. This work offers a way to deeply understand the assembly process of intricate lanthanide-antimony(III) oxohalide structures at the atomic level.

Stibonic acids and related stibonate-phosphonate clusters: Synthesis, characterization and bioactivity evaluation

The reaction of 4-(azobenzene)phenylstibonic acid with t-butylphosphonic acid led to the isolation of the tetranuclear oxo-hydroxo antimony cluster of formulae [(4-azobenzene-C6H4Sb)4(OH)4(tBuPO3)6] (C1). The reaction of (p-t-butyl phenyl stibonic acid with phenyl phosphonic acid resulted in the isolation of complex with formulae [(p-t-BuC6H4Sb)4(O)2(PhPO3)4(PhPO3H)4] (C2). Based upon the initial results from docking studies, parent stibonic acids, t-butyl-phenylstibonic acid, p-isopropylphenylstibonic acid, 4-azobenzenephenylstibonic acid, and the derived tetranuclear organoantimonate-phosphonate clusters were screened against different cancer cell lines, various Gram-positive and Gram-Negative bacteria and mycobacteria for possible bioactivity profile.

Polyoxocationic antimony oxide cluster with acidic protons

The success and continued expansion of research on metal-oxo clusters owe largely to their structural richness and wide range of functions. However, while most of them known to date are negatively charged polyoxometalates, there is only a handful of cationic ones, much less functional ones. Here, we show an all-inorganic hydroxyiodide [H10.7Sb32.1O44][H2.1Sb2.1I8O6][Sb0.76I6]2·25H2O (HSbOI), forming a face-centered cubic structure with cationic Sb32O44 clusters and two types of anionic clusters in its interstitial spaces. Although it is submicrometer in size, electron diffraction tomography of HSbOI allowed the construction of the initial structural model, followed by powder Rietveld refinement to reach the final structure. The cationic cluster is characterized by the presence of acidic protons on its surface due to substantial Sb3+ deficiencies, which enables HSbOI to serve as an excellent solid acid catalyst. These results open up a frontier for the exploration and functionalization of cationic metal-oxo clusters containing heavy main group elements.

Laser Ablation Generation of Antimony Selenide Clusters: Laser Desorption Ionization (LDI) Quadrupole Ion Trap Time of Flight Mass Spectrometry.

The binary system Sb-Se was studied via laser ablation using antimony-selenium mixtures made from powdered elements in various ratios generating new SbmSen clusters. The results show that in addition to Sbm+ (m =1-8) and Sen+ (n = 2-9) clusters, a series of SbmSen+ clusters such as SbSe1-8+, Sb2Se1-6+, Sb3Se1-5+, Sb4Se1-3+, and Sb5Se1,2+ is generated. In addition, some low intensity oxidized clusters like Se6O2+, Se7O2+, and SbSe2-6O5+ and partially hydroxylated clusters (SbSeO2H7+, SbSe5O4H+) are also formed. In total, 24 new antimony selenide clusters were generated. The knowledge gained can contribute to the elucidation of the structure of SbmSen glasses. Graphical Abstract.

Recent Advances in Aromatic Antimony Clusters

AbstractThis paper highlights the compounds containing Sb cluster fragments, either synthesized in the solid‐state, discovered from the gas phase, or only theoretically predicted. These Sbn clusters feature unique chemical bonding, fascinating structures, and special stabilities that can be well rationalized by aromaticity or antiaromaticity. A deep understanding to their electronic structures is essential and will greatly facilitate the experimental synthesis of new Sbn cluster‐based materials.

Synthesis and structural phase transitions of [Mg2Sb2(C4H2O6)2(H2O)8](ClO4)2·5H2O with complex homochiral chains

Abstract A new magnesium antimony tartrate perchlorate [Mg2Sb2(C4H2O6)2(H2O)8](ClO4)2·5H2O, 1, was synthesized in single crystal form by slowly evaporating an aqueous solution of potassium antimony tartrate and magnesium perchlorate. In the temperature interval 298 K–123 K, the compound undergoes two reversible structural phase transitions. The transition from phase I to phase II at ca. 236 K is second order and the transition from phase II to phase III at ca. 144 K is first order. Phase I has an orthorhombic structure, P21212, a=11.8658(4) Å, b=16.464(1) Å, c=8.3895(4) Å at 298 K, containing infinite chains of antimony tartrate dimeric clusters bridged by MgO2(H2O)4 octahedra. The ClO4 − anions occupying the interchain space show pronounced dynamic disorder. Phase II is monoclinic, P21, a=8.3813(8) Å, b=11.760(1) Å, c=16.289(2) Å, β=92.442(2)° at 153 K. Phase III has an orthorhombic unit cell with quadrupled cell volume, P212121, a=11.6914(8) Å, b=16.176(1) Å, c=33.426(2) Å at 123 K. While the infinite chains in phases II and III are closely similar to those in phase I, the ClO4 − anions show different orientations and gradual disappearance of dynamic disorder as the temperature is lowered.

DFT investigation of the influence of Jahn–Teller distortion on the aromaticity in square-planar arsenic and antimony clusters

Density functional theory (DFT) calculations were performed to investigate aromaticity of tetra atomic metalloid clusters, As42− and Sb42−. The careful analysis of nuclear independent chemical shifts (NICS) revealed strong σ antiaromatic and week π aromatic character of investigated species. This unexpected behavior is explained through the analysis of antagonistic paratropic and diatropic contributions, and with detailed adaptive natural density partitioning (AdNDP) analysis. Furthermore, we investigated aromatic/antiaromatic behavior of Jahn–Teller (JT) active species As4− and Sb4−. NICS parameters have been scanned along the Intrinsic Distortion Path (IDP) showing strong antiaromaticity which decreases with increasing deviation from D4h to D2h symmetry.

Fractal growth in the presence of a surface force field

We numerically simulate the dynamics of atomic clusters aggregation deposited on a surface interacting with the growing island. We make use of the well-known DLA model but replace the underlying diffusion equation by the Smoluchowski equation which results in a drifted DLA model and anisotropic jump probabilities. The shape of the structures resulting from their aggregation-limited random walk is affected by the presence of a Laplacian potential due to, for instance, the surface stress field. We characterize the morphologies we obtain by their Hausdorff fractal dimension as well as the so-called external fractal dimension. We compare our results to previously published experimental results for antimony and silver clusters deposited onto graphite surface.

Fast decay of 4p and 4s core holes in Sb4 clusters

The 4s and 4p photoelectron spectra of a vapour phase Sb4 antimony cluster have been recorded using synchrotron radiation excitation. Relativistic multiconfiguration Dirac–Fock calculations have been used to predict the spectral features. The strongly different lifetime widths of the two energetically close-lying orbitals have been observed and the existing fast Auger channels are modelled.

Characterization of a template process for conducting cluster-assembled wires

Bismuth and antimony clusters have been deposited onto spin coated PMMA layers patterned by electron-beam exposure. The probability of reflection or adhesion of the clusters from the PMMA depended on its surface roughness, determined by the electron-beam exposure dose. The Bi and Sb clusters exhibited a significantly higher probability of reflection from unexposed PMMA than from Si3N4 (grown by plasma enhanced chemical vapor deposition) despite the approximately equal surface roughness of these layers. By exploiting this difference in adhesion/reflection, a cluster-assembled wire was grown between four-point planar electrodes. Four-probe electrical measurements yielded linear current-voltage (I(V)) characteristics whilst non-linear I(V) characteristics were obtained from two-probe measurements. An established model provided good agreement with two-probe conductance-voltage and resistance-temperature data. Tunneling barriers between the cluster wire and the planar electrodes are believed to have caused the non-linear two-point I(V) characteristics.

The Unique Palladium-Centered Pentagonal Antiprismatic Cationic Bismuth Cluster: A Comparison of Related Metal-Centered 10-Vertex Pnictogen Cluster Structures by Density Functional Theory

Structures for the metal-centered 10-vertex pnictogen clusters M@Pn(10)(4+) (M = Ni, Pd, Pt; Pn = As, Sb, Bi) based on polyhedra with 3-fold, 4-fold, and 5-fold symmetry have been studied by density functional theory. Among these nine M/Pn combinations, only Pd@Bi(10)(4+) and Pt@Bi(10)(4+) are predicted to have the D(5d) pentagonal antiprism as the lowest energy structure in accord with experimental observation of this cluster in the ternary halide Bi(14)PdBr(10) as well as the prediction of the Wade-Mingos rules for these arachno systems. The lowest energy structures for the arsenic and antimony clusters M@Pn(10)(4+) (Pn = As, Sb) and Ni@Bi(10)(4+) are predicted to have structures derived from a tetracapped trigonal prism that has been severely distorted for M@As(10)(4+) (M = Pd, Pt). The volumes of the As(10) polyhedra other than the pentagonal prism are too small to contain interstitial palladium or platinum atoms so that major distortions are predicted for such clusters leading to partial opening of the polyhedron.

Group theoretical treatment of Jahn–Teller versus spin-orbit effects on geometries, rovibronic levels and nuclear spin species of bismuth and antimony clusters

Clusters of very heavy group 15 elements, particularly those of Sb and Bi are intriguing due to the interplay of vibronic and relativistic effects, which quench the Jahn–Teller distortion, and thus resulting in the retention of higher symmetry in the double group. Group theoretical treatment of Bi n clusters and comparisons with Sb n clusters as a function of cluster size and coordination polyhedra has been carried out. The spin-orbit and Jahn–Teller effects have dual roles, thus resulting in interesting rovibronic and nuclear spin species arising from spin-9/2 209Bi. The rovibronic and nuclear spin species of 121Sb and 123Sb are also quite interesting due to their equal relative abundance and high nuclear spin. It has been shown by using group theoretical and combinatorial methods that these clusters exhibit interesting nuclear spin multiplets and distributions of rovibronic levels as a function of polyhedral geometry, which is influenced by the quenching of Jahn–Teller pseudorotation by spin-orbit effects in heavier Bi n clusters. The results are contrasted with Sb n clusters which undergo Jahn–Teller pseudorotations. It is also pointed out how the techniques considered here can be applied to Tl n and In n clusters.

Antimony clusters in channels of porous silica ZSM-11

The structure and arrangement of the nanosized antimony clusters synthesized in channels of ZSM-11 porous silica crystals are studied using maximum entropy (MEM) and Rietveld methods. Intercalated antimony atoms are not randomly located in zeolite channels; rather, they form distorted cubic clusters Sb8, with shapes coinciding with that of a fragment of crystalline antimony. The distances between the nearest-neighbor antimony atoms in a cluster are 2.86(6) and 2.88(4) A. The maximum cluster size (4.92 A) matches the minimum free channel diameter of zeolite ZSM-11. The minimum Sb-O distance is 2.68(6) A.

Cluster size effect on the electric polarizability and hyperpolarizability in small antimony clusters Sb n, n = 1, 2 and 4

We have obtained static polarizabilities and hyperpolarizabilities for small antimony clusters Sb n , n = 1, 2 and 4, relying on high-level conventional ab initio and density-functional theory calculations with purpose-oriented basis sets. Our best values for the mean dipole polarizability and second dipole hyperpolarizability are α ¯ / e 2 a 0 2 E h - 1 = 42.55 ( Sb ) , 93.67 (Sb 2) and 206.09 (Sb 4) and 10 - 3 γ ¯ / e 4 a 0 4 E h - 3 = 11.4 ( Sb ) , 35.0 (Sb 2) and 120.5 (Sb 4). Our results show that, for both properties, the mean value per-atom increases with cluster size.

Structural and electronic properties ofSbn(n=2–10)clusters using density-functional theory

Using a density-functional calculation within the generalized gradient approximation, we have investigated the structural and electronic properties of antimony clusters. The lowest-energy structures of neutral and anionic ${\mathrm{Sb}}_{n}$ clusters up to $n=10$ were determined and compared with those of light-element group-V clusters $({\mathrm{As}}_{n},{\mathrm{P}}_{n})$. The size dependence of binding energies, gaps between lowest-unoccupied and highest-occupied molecular orbitals, second-order difference of total energies, and adiabatic electron affinities (EAs) of ${\mathrm{Sb}}_{n}$ clusters were discussed. Even-odd oscillation as well as magic-number behavior at ${\mathrm{Sb}}_{4}$ were observed. Qualitative agreement was found between theoretical and experimental EAs.

Triosmium–antimony clusters containing the μ,η 2-phenylene ligand: Unusually long osmium–osmium bonds

The reaction of the osmium–antimony cluster Os 3(μ-H)(μ-SbPh 2)(μ 3,η 2-C 6H 4)(CO) 9 with AsPh 3 at room temperature afforded the o-phenylene cluster Os 3(μ-H)(SbPh 2)(μ 2,η 2-C 6H 4)(CO) 9(AsPh 3) by nucleophilic addition via a metal–metal bond cleavage, and the substitution product Os 3(μ-H)(SbPh 2)(μ 3,η 2-C 6H 4)(CO) 8(AsPh 3). It reacted with t BuNC to afford the adduct Os 3(μ-H)(SbPh 2)(μ 2,η 2-C 6H 4)(CO) 9(CN t Bu) quantitatively. This adduct isomerised slowly on standing via migration of the isonitrile, while photolysis led to decarbonylation to Os 3(μ-H)(SbPh 2)(μ 2,η 2-C 6H 4)(CO) 8(CN t Bu). All the products have been characterised completely, including by X-ray crystallography, and their structures exhibit very long Os–Os bonds.

Templated-assembly of conducting antimony cluster wires

Wires with meso- and nanoscale widths have been fabricated using a novel assembly techniquebased on the deposition of Sb clusters on templated surfaces. The template elements areV-grooves etched into the surface of a Si wafer. It is demonstrated that the clusters bounceor slide to the apex of the V-grooves, without significant fragmentation, and that thismotion is the underlying mechanism behind the formation of the wires. The flow rate ofinert gas into the cluster growth chamber controls the average velocity of the clusters andthe morphology and width of the wires. Sb cluster-assembled wires with lengths over150 µm and widths down to 100 nm have been assembled from nm diameter Sb clusters. Electrical contacts to the wires have been achieved vialithographic alignment of NiCr/Au contacts to the V-grooves prior to deposition.

Monte Carlo simulation on the initial stage of islands growth by soft-landed clusters

The morphology of antimony islands grown on the graphite surfaces from soft-landed clusters is investigated by applying the dynamical Monte Carlo method to a lattice gas model. The graphite surface is treated as a triangular lattice subject to a periodic boundary condition. Each incident antimony cluster just after impinging to the surface is assumed to adsorb with a compact shape and to migrate on the surface as a mobile cluster having a multilayer structure. Stable islands are also assumed to grow by the coalescence of mobile clusters. In simulations, two types of processes to make the island shape compact are introduced in order to reproduce the characteristic morphologies of antimony islands on graphite surfaces: jumping up of atoms from convex positions at the perimeter of islands to higher layers of the islands, jumping down from higher layers to empty sites at concave positions around islands. In addition, the multilayer structure of islands is approximately treated with an effective double layer model in which higher layers except for the base are substituted by a uniform effective layer characterized only with the density. The simulation shows the rather compact growth of islands for small cluster deposition. A tendency to the ramified growth of islands is also obtained in the simulation for larger cluster deposition. These results are similar to the observed morphology of antimony islands on graphite surfaces.

Size-dependent phase transition from amorphous to crystalline in antimony clusters on crystalline surfaces

Size-dependent phase transition from amorphous to crystalline in antimony clusters on crystalline surfaces