Quantum chemical study of IrFn (n = 1–7) clusters: An investigation of superhalogen properties

In present investigation, the interactions of iridium (Ir) atom with fluorine (F) atoms have been studied using the density functional theory. Up to seven F atoms were able to bind to a single Ir atom which resulted in increase of electron affinities successively, reaching a peak value of 7.85 eV for IrF₇. The stability and reactivity of these clusters were analyzed by calculating highest occupied molecular orbital (HOMO)–LUMO gaps, molecular orbitals and binding energies of these clusters. The unusual properties of these clusters are due to the involvement of inner shell 5d‐electrons, which not only allows IrF_n clusters to belong to the class of superhalogens but also shows that its valence can exceed the nominal value of 2. © 2012 Wiley Periodicals, Inc.     

Theoretical investigations on the superhalogen properties and interaction of PdOn (n = 1–5) species

Density functional calculations on the ground state geometries and stabilities of PdO_n species (n = 1–5) are performed in neutral as well as anionic forms. Calculations reveal that Pd can bind stably with four O atoms indicating the maximum oxidation state of Pd as high as +8. The electron affinities of PdO_n suggest that these species behave as superhalogens for n ≥ 2. The large electron affinities of PdO_n species along with stability of their anions point toward the synthesis of new class of compounds having unusual oxidizing capabilities. This possibility is explored by considering the interaction of PdO₂ superhalogen with Ca atom which forms a stable CaPdO₂ complex. In this complex, PdO₂ unit closely mimics the behavior of O atom when compared with CaO molecule. © 2013 Wiley Periodicals, Inc.     

Synthesis,structure and magnetism of a new ionic pentanuclear iron cluster

A new ionic pentanuclear Fe^III cluster, namely, triethylazanium tetrakis(μ₂‐5‐amino‐1,2,3,4‐tetrazolido)tetrakis(μ₃‐4‐chloro‐2‐{[(1H‐tetrazol‐1‐id‐5‐yl)imino]methyl}phenolato)di‐μ₃‐oxido‐pentairon(III) acetonitrile monosolvate monohydrate, (C₆H₁₆N)[Fe₅(C₈H₄ClN₅O)₄(CH₂N₅)₄O₂]·CH₃CN·H₂O, was synthesized using microvial synthesis methods and characterized by elemental analysis, FT–IR spectroscopy, single‐crystal X‐ray diffraction and thermogravimetric analysis. Magnetic studies reveal that the complex displays dominant antiferromagnetic intracluster interactions between the Fe^III ions through the μ₃‐oxide bridges.     

Energies and Spin States of FeS0/−, FeS20/−, Fe2S20/−, Fe3S40/−, and Fe4S40/− Clusters

The structures and energies of the electronic ground states of the FeS^0/?, FeS₂^0/?, Fe₂S₂^0/?, Fe₃S₄^0/?, and Fe₄S₄^0/? neutral and anionic clusters have been computed systematically with nine computational methods in combination with seven basis sets. The computed adiabatic electronic affinities (AEA) have been compared with available experimental data. Most reasonable agreements between theory and experiment have been found for both hybrid B3LYP and B3PW91 functionals in conjugation with 6‐311+G* and QZVP basis sets. Detailed comparisons between the available experimental and computed AEA data at the B3LYP/6‐311+G* level identified the electronic ground state of ⁵Δ for FeS, ⁴Δ for FeS^?, ⁵B₂ for FeS₂, ⁶A₁ for FeS₂^?, ¹A₁ for Fe₂S₂, ⁸A′ for Fe₂S₂^?, ⁵A′′ for Fe₃S₄, ⁶A′′ for Fe₃S₄^?, ¹A₁ for Fe₄S₄, and ¹A₂ for Fe₄S₄^?. In addition, Fe₂S₂, Fe₃S₄, Fe₃S₄^?, Fe₄S₄, and Fe₄S₄^? are antiferromagnetic at the B3LYP/6‐311+G* level. The magnetic properties are discussed on the basis of natural bond orbital analysis.     

The highest oxidation state of Au revealed by interactions with successive cl ligands and superhalogen properties of AuCln (n = 1–6) species

This study deals with a reinvestigation on the maximum oxidation state of gold. Density functional calculations are performed on geometries and stabilities of AuCl_n species for n = 1–6 in their neutral and anionic states. The calculations clearly reveal that the maximum oxidation state of Au is limited to +5. The high adiabatic electron affinities of AuCl_n (n ≥ 2), as compared to Cl, suggest their superhalogen behavior. The interaction of AuCl_n superhalogens with an alkali metal, K is found to be similar to but stronger than that between K and Cl, leading to the formation of KAuCl_n complexes. The stabilities of these complexes explore the possibility of synthesis of new class of salts by interaction of with appropriate metal cations. © 2014 Wiley Periodicals, Inc.     

From molecule to materials: crystalline superlattices of nanoscopic CdS clusters

Make way for a superlattice! A crystalline 3D superlattice of 2.3?nm molecular CdS nanoclusters was prepared from a convenient mononuclear cadmium thiophenolate precursor. HRTEM and STEM tomography show highly crystalline repetition of monodisperse frameworks. This combined with elemental and thermogravimetric analyses suggests an approximate formula [Cd(130)S(103)(SPh)(54)].     

Pnictogen‐containing iron and chromium carbonyl complexes: From complexes to semiconducting frameworks

Recently, main group elements containing transition metal carbonyl complexes have received much attention due to their novel bonding modes and versatile reactivities. In this article, we will focus on the development of pnictogen (Bi, Sb, and As)‐containing Fe or Cr carbonyl complexes reported in our previous study, in which their rational synthetic methodologies, intriguing reactivities, as well as their special properties will be described and systematically compared. Importantly, a unique zig‐zag Bi‐Fe polymer was synthesized, and several Bi‐Cr complexes were found to exhibit surprising semiconducting behaviors with varied ultra‐low energy gaps via the through‐bond or through‐space electron communication.     

Synthesis and selected properties of Co3Fe4V6O24

A new compound Co₃Fe₄V₆O₂₄ has been obtained by solid state reaction. Temperature of its incongruent melting amounts to 890±5°C. Results of indexing the powder diffraction pattern and unit cell parameters of Co₃Fe₄V₆O₂₄ are also given. This compound is probably isostructural with M₃Fe₄V6O₂₄ (where M = Zn, Mg, Mn). IR spectrum of Co₃Fe₄V₆O₂₄ phase is presented. This revised version was published online in July 2006 with corrections to the Cover Date.     

High-nuclearity homometallic iron and nickel clusters: Fe22 and Ni24 complexes from the use of N-methyldiethanolamine

The use of N-methyldiethanolamine (mdaH2) in reactions with Fe(III) and Ni(II) sources has led to Fe22 and Ni24 products; the clusters are the highest and second-highest, respectively, homometallic clusters for these metals to date, and possess S = 0 and S = 6 ground states, respectively.     

Fe4Si2Sn7O16: Eine Kombination von FeSn6-Oktaedern mit Schichten von (Fe3Sn)O6-Oktaedern; Präparation,Eigenschaften und Kristallstruktur [1]

Fe₄Si₂Sn₇O₁₆: A Combination of FeSn₆-Octahedra with Layers of (Fe₃Sn)O₆-Octahedra; Preparation, Properties, and Crystal Structure Fe₄Si₂Sn₇O₁₆ has been prepared by a solid state reaction at 900 °C from a mixture of Fe₂O₃, SnO₂, Sn, and Si. The compound is a paramagnetic semiconductor. Results of Mössbauer and suszeptibility measurements as well as bond length-bond strength calculations lead to the possible ionic formulation Fe₄²⁺Si₂⁴⁺Sn₁²⁺Sn₁⁴⁺O₁₆^2–. The compound crystallizes in the trigonal space group P3m1 (no. 164), with one formula unit per cell. Lattice parameters obtained by powder measurements are: a = 6.8243(6) Å, c = 9.1404(6) Å, γ = 120°, V = 368.6(1) ų. The structure consists of layers of edge linked oxygen octehedra exactly centered by Sn and Fe in the ratio 1 : 3. Three plains of isolated SiO₄ tetrahedra, FeSn₆ octahedra and again SiO₄ terahedra are inserted between two such layers. The layers are stacked along [001] and linked three-dimensionally by oxygen.     

An iron (II) guanidinate compound: Synthesis,characterization, thermal properties and its application as a CVD precursor for iron oxide film

An iron compound containing guanidinate ligand [Fe((SiMe₃)₂NC(ⁱPrN)₂)₂] was synthesized using a conventional lithium‐salt‐elimination reaction, and its chemical structure was characterized through elemental analysis, ¹H‐NMR and single‐crystal X‐ray diffraction, respectively. The thermal properties of the compound were examined through thermogravimetric analysis (TGA), and the TGA results demonstrated that the compound possessed sufficient volatility and suitable thermal stability for the CVD process. Moreover, the deposition experiments were conducted using the synthesized compound as a precursor and O₂ as an oxygen source to confirm its applicability as a CVD precursor, and α‐Fe₂O₃ films were successfully deposited at a relatively low deposition temperature (300°C).     

ChemInform Abstract: Fe4Si2Sn7O16: A Combination of FeSn6-Octahedra with Layers of (Fe3Sn)O6-Octahedra; Preparation,Properties, and Crystal Structure.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

Solvatothermal Syntheses and Structural Characterizations of Polyoxoalkoxometalates: The Heptanuclear [{Fe(OH)(CH3CN)2} Fe6OCl6{(OCH2)3CCH2OH}4], the Decanuclear [Fe10O2Cl8{(OCH2)3CCH2CH3}6], and the Bimetallic [(VO)2Fe8O2Cl6{(OCH2)3CCH2CH3}6]

Solvatothermal syntheses have been exploited to effect the isolation of three novel polyoxoalkoxometalate clusters, [{Fe(OH)(CH₃CN)₂} Fe₆OCl₆{(OCH₂)₃CCH₂OH}₄] (1), [Fe₁₀O₂Cl₈{(OCH₂)₃CCH₂CH₃}₆] (2), and [(VO)₂Fe₈O₂Cl₆{(OCH₂)₃CCH₂CH₃}₆] (3). The structure of 1 may be described as a hexametalate core {Fe₆OCl₆}¹⁰⁺, consisting of a octahedral arrangement of chloride ligands encasing an octahedron of six Fe(III) sites, with a central oxo group. The remaining four coordination sites at each octahedral iron center are occupied by doubly bridging oxygen donors from the trisalkoxo ligands. One triangular face of this substructure, defined by three oxygen atoms, from three adjacent trisalkoxo ligands, is capped by the {Fe(OH)(CH₃CN)₂}²⁺ subunit. The structure of 2 is based on the decametalate core of edge-sharing octahedra. The eight peripheral Fe(III) sites of the cluster bond to four oxygen donors from the trisalkoxo ligands, a terminal Cl^– ligand, and one of the ⁶-oxo groups. The two central iron sites are linked to four oxygen donors from the trisalkoxo ligands and to both of the ⁶-oxo groups. Cluster 3 is structurally related to 2 with two {FeCl}²⁺ units replaced by {VO}²⁺ groups.     

A New Structure Type for Rare-Earth-Metal Cluster Compounds stabilized by transition metals: KPr6I10Os,CsPr6I10Fe,CsLa6I10Fe,and CsLa6I10Mn

Reactions of KI, Pr, PrI₃, and Os in niobium tubes at 800° yielded black, air- and moisture-sensitive crystals of Kpr₆I₁₀Os which were characterized by single crystal X-ray diffraction (orthorhombic, Pnma, a = 15.362(3), b = 13.498(2), c = 14.128(3) Å, Z = 4, R(F)/R_w = 4.4/5.6%). Subsequent parallel experiments also gave, according to Guinier powder pattern data, the isostructural compounds CsPr₆I₁₀Fe (a = 15.312(2), b = 13.426(1), c = 14.154(1) Å), CsLa₆I₁₀Fe (a = 15.523(2), b = 13.646(2), c = 14.334(1) Å) and CsLa₆I₁₀Mn (a = 15.457(4), b = 13.737(2), c = 14.329(2) Å). The important structural feature is the presence of octahedral rare-earth-metal cluster units R₆ that are centered by a transition-metal atom Z and bridged and interconnected by halide atoms. The new compounds exhibit the same general pattern of halide connectivity (R₆Z)XXXX as do the triclinic compounds R₆X₁₀Z. However, the structural arrangement of the metal octahedra is significantly different; they are linked by I^i–i atoms into zigzag chains along [010] and these are interconnected into a three dimensional network by I^i–a atoms to form channels in which the alkali-metal atoms are located. The introduction of alkali-metal atoms into reactions leads to new quaternary compounds with discrete rare-earth-metal clusters centered by transition metals and more open structure frameworks. Measurements of the temperature dependencies of the magnetic susceptibilities for CsLa₆I₁₀Fe and CsLa₆I₁₀Mn are consistent with expectations for 17- and 16-electron cluster systems, respectively.     

Synthesis, structure and magnetic properties of the one-dimensional bimetallic oxide [Cu(terpy)Mo2O7]

The hydrothermal reaction of Cu(CH₃CO₂)₂·H₂O, Na₂MoO₄ and terpyridine at 140 °C for 48 h yields [Cu(terpy)Mo₂O₇] (1), a bimetallic one-dimensional oxide. The structure consists of ruffled chains of edge- and corner-sharing {MoO₅} square pyramids, decorated with {CuN₃O₂} ‘4+1’ axially distorted square pyramids. The Cu(II) polyhedra are disposed so as to produce an alternating pattern of Cu-Cu distances across the {Mo₂O₂} rhombi of the chain of 6.25 and 6.82 Å. This structural feature is reflected in the magnetic properties which are characteristic of a dimer rather than a linear chain, consistent with an alternating antiferromagnetic Heisenberg chain.