Standard enthalpy of the formation of Ba[AuF6]2 · 4KrF2(cr.)

Enthalpies of the interaction of Ba[AuF₆]₂ · 4KrF₂(cr.) with water and an aqueous potassium hydroxide solution are measured at 298.15 K in a calorimeter with an isothermal shell. On the basis of these results and the literature data, the standard enthalpy of the formation of the studied compound Δ_f H° Ba[AuF₆]₂ · 4KrF₂(cr.) = −3036 ± 21 kJ/mol are found using two independent methods.     

The Thermal Dehydration of Magnesium Aluminum Pentafluoride Dihydrate: Crystal Structures of MgAlF5(H2O)2 and MgAlF5

 Small plate-like single crystals of MgAlF₅(H₂O)₂ have been obtained during hydrothermal treatment (270°C) of microcrystalline material prepared by precipitation of stoichiometric solutions of Al₂(SO₄)₃ ·  18H₂O and Mg(NO₃)₂ · 6H₂O with diluted hydrofluoric acid. The crystal structure of MgAlF₅(H₂O)₂ has been refined from single crystal data (Imma (# 74), Z = 4, a = 7.0637(7), b = 10.1308(10), c = 6.7745(7) ?, 398 structure factors, 33 parameters, R(F² > σ(F ²)) = 0.0245, wR(F² all) = 0.0525). Main features of the inverse weberite type structure are infinite chains of trans-bridged [AlF₆] octahedra which are connected via common fluorine atoms by isolated [MgF₄(H₂O)₂] octahedra. MgAlF₅(H₂O)₂ dehydrates at temperatures above 300°C to give MgAlF₅. XRPD analysis of this phase has revealed isotypism with FeAlF₅. The crystal structure of MgAlF₅ (Immm (# 71), Z = 2, a = 7.268(1), b = 6.123(2), c = 3.543(1) ?) is built of infinite chains of edge-sharing [MgF₆] octahedra and chains of corner-sharing [AlF₆] octahedra along [001]. Upon further heating to temperatures above 500°C, MgAlF₅ decomposes to MgF₂ and α − AlF₃.     

New Bimetallic Ni–Rh Carbonyl Clusters: Synthesis and X-ray Structure of the [Ni7Rh3(CO)18]3?, [Ni3Rh3(CO)13]3? and [NiRh8(CO)19]2? Cluster Anions

The reaction of the [Ni₆(CO)₁₂]²⁻ dianion with [Rh(COD)Cl]₂ (COD = cyclooctadiene) in acetone affords a mixture of bimetallic Ni–Rh clusters, mainly consisting of the new [Ni₇Rh₃(CO)₁₈]³⁻ and [Ni₈Rh(CO)₁₈]³⁻ trianions. A study of the reactivity of [Ni₇Rh₃(CO)₁₈]³⁻ led to isolation of the new [Ni₃Rh₃(CO)₁₃]³⁻ and [NiRh₈(CO)₁₉]²⁻ anions. All these new bimetallic Ni–Rh carbonyl clusters have been isolated in the solid state as tetrasubstituted ammonium salts and have been characterised by elemental analysis, X-ray diffraction studies, ESI-MS and electrochemistry. The unit cell of the [NEt₄]₃[Ni₇Rh₃(CO)₁₈] salt contains two orientationally-disordered ν₂-tetrahedral [Ni₇Rh₃(CO)₁₈]³⁻ trianions with occupancy factors of 0.75 and 0.25. Besides, their inner Ni₃Rh₃ octahedral moieties show two cis sites purely occupied by Rh atoms, two trans sites purely occupied by Ni atoms and the remaining two cis sites are disordered Ni and Rh sites with respective occupancy fraction of 0.5. At difference from the parent [Ni₇Rh₃(CO)₁₈]³⁻, the octahedral [Ni₃Rh₃(CO)₁₃]³⁻ displays an ordered distribution of Ni and Rh atoms in two staggered triangles. The [NiRh₈(CO)₁₉]²⁻ dianion adopts an isomeric metal frame with respect to that of the [PtRh₈(CO)₁₉]²⁻ congener. As a fallout of this work, new high-yield synthesis of the known [Ni₆Rh₃(CO)₁₇]³⁻ and [Ni₆Rh₅(CO)₂₁]³⁻, as well as other currently-investigated bimetallic Ni–Rh clusters have been obtained.     

Standard enthalpy of formation of (NO2)2[NiF6](cr)

The enthalpies of interactions of (NO₂)₂[NiF₆](cr) with water and aqueous KOH, enthalpies of solution of KF(cr) in dilute aqueous solutions of KNO₃ and KOH, and enthalpy of mixing of solutions of NiF₂, HNO₃, and HF were measured at 298.15 K using isothermic-shell calorimeters. Based on the obtained data and values in the literature, the standard enthalpy of formation of the compound under study was determined by two independent methods: Δ_f H°(NO₂)₂[NiF₆](cr) = −1099 ± 9 kJ/mol.     

Structural characterization of a novel self-assembly heterohexanuclear complex: [Ni2Ag4(μ-dppm)4(pymt)6](SbF6)2 · 2DMF · H2O

A novel heterohexanuclear complex [Ni₂Ag₄(μ-dppm)₄(pymt)₆](SbF ₆)₂ · 2DMF · H₂O (1), was synthesized by self-assembly with [Ag₂(μ-dppm)₂(MeCN)₂](SbF₆) ₂ and [Et₄N][Ni(pymt)₃] (dppm = bis(diphenylphosphino)methane, pymt = pyrimidine-2-thiolate) as components and characterized by IR spectra, elemental analysis, ¹H-NMR spectrum, ³¹P-NMR spectrum and Visible-Ultraviolet spectrum. Structure of the complex was determined by X-ray analysis.     

Standard enthalpy of formation of (ClOF2)2[NiF6](cryst.)

The enthalpies of reaction between crystalline (ClOF₂)₂[NiF₆] and water and an aqueous solution of alkali are measured at 298.15 K using a highly sensitive isothermal shell calorimeter. On the basis of these values and the published data, the standard enthalpy of formation of the studied compound is found by two independent methods; its value is Δ _f H^o(ClOF₂)₂[NiF₆]](cryst.) = −1158 ± 11 kJ/mol.     

Crystal structure of barium trans (O)- cis (CN)-Bis(2-picolinato)dicyanocobaltate(III) hydrate [Ba(H2O)4][Co(Pic)2(CN)2]2 · 4.41H2O

In the crystals of [Ba(H₂O)₄][Co(Pic)₂(CN)₂]₂ · 4.41H₂O (tetragonal system, a = b = 10.9390(4) ?, c = 31.7624(15) ?, Z = 4, space group P4₃), the trans(O)-cis(CN)-[Co(Pic)₂(CN)₂]⁻ anions are incorporated into cellular infinite layers whose sites contain Ba²⁺ ions, which are connected to four neighboring complexes through the oxygen atoms of the carboxy groups of the 2-picolinate ions. Four O atoms of the water molecules complete the Ba coordination polyhedron to a distorted square antiprism. Original Russian Text ? M. Zabel, V.I. Pavlovskii, A.L. Poznyak, 2007, published in Zhurnal Neorganicheskoi Khimii, 2007, Vol. 52, No. 3, pp. 417–420.     

Synthesis and Crystal Structure of Cucurbit[6]uril Adduct of Hydrogen-bonded Cluster Complex [Mo3(μ3-Se)(μ2-O)3(H2O)6Cl3]+

Reaction of [MoOCl₅]²⁻ with in situ generated H₂Se under hydrothermal conditions (4M HCl, 140 °C) leads to reduction of Mo(V) to Mo(IV) with the formation of a triangular cluster Mo₃(μ₃-Se)(μ-O)₃⁴⁺ in high yield. It is present in HCl solutions as aqua chlorocomplex [Mo₃(μ₃-Se)(μ-O)₃(H₂O)₆Cl₃]⁺ which was isolated and structurally characterized as supramolecular adduct with cucurbit[6]uril (CB[6]), {[Mo₃(μ₃-Se)(μ-O)₃(H₂O)₆Cl₃]₂CB[6]}Cl₂·15H₂O. Dedicated to Professor Dieter Fenske on the Occasion of his 65th Birthday     

Synthesis and crystal structure of KNa3[Fe3O(CH3COO)6(H2O)2]3 [α-P2W17Fe(H2O)O61]·32.5H2O

A complex of the composition KNa₃[Fe₃O(CH₃COO)₆(H₂O)₃]₃ [α-P₂W₁₇Fe(H₂O)O₆₁]·32.5H₂O (I) was obtained by interaction of FeCl₃·6H₂O and phosphotungstate K₁₀[α₂-P₂W₁₇O₆₁]·20H₂O in an acetate buffer with a yield of 52%. Compound I was characterized by single crystal X-ray phase analysis and IR spectroscopy. In the crystal structure, the Na and K cations bind [Fe₃O(CH₃COO)₆(H₂O)₃]⁺ trinuclear cations and [α-P₂W₁₇Fe(H₂O)O₆₁]⁷⁻ heteropolytungstate anions into infinite zigzag chains. Original Russian Text Copyright ? 2005 by N. V. Izarova, M. N. Sokolov, A. V. Virovets, H. G. Platas, and V. P. Fedin __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 46, No. 1, pp. 149–155, January–February, 2005.     

Crystal and molecular structure of (NH4)2[UO2(NO3)4] and [(NH4)(18C6)]2[UO2(NO3)4]

Single crystals of diammonium tetranitratouranylate (NH₄)₂[UO₂(NO₃)₄] (I) and a new diammonium tetranitratouranylate complex with 18-crown-6 [(NH₄)(18C6)]₂[UO₂(NO₃)₄] (II) have been synthesized by the reaction of diaquadinitratouranyl tetrahydrate with ammonium nitrate in a nitric acid solution and the reaction of the same reagents with 18C6 in an ethanol solution, respectively. The X-ray diffraction analysis of compounds I and II has been performed. Crystals of compounds I and II are monoclinic, Z = 2, space group P2₁/n, a = 6.4075(5) ?, b = 7.7851(7) ?, c = 12.4461(12) ?, β = 101.239(1)°, V = 608. 94(9) ?³ for compound I and a = 10.542(9) ?, b = 8.590(8) ?, c = 22.5019(19) ?, β = 101.632(1)°, V = 2058.3(3) ?³ for compound II. The [UO₂(NO₃)₄]²⁻ complex anion in compounds I and II contains two monodentate and two bidentate cyclic nitrato groups, and the coordination number of uranyl is 6. The 18C6 molecule in the structure of compound II has the classic crown conformation and combined with the ammonium ion by three hydrogen bonds. Compounds I and II formed by electrostatic attraction forces between counterions are stabilized by (NH₄⁺)NH...O(NO₃⁻) interionic hydrogen bonds.     

Investigating the Thermolysis Products of [Cd10Se4(SePh)12(P n Pr3)4] – The New Cluster Ion [Cd17Se4(SePh)28]2?

Analytical studies on the thermolysis products from [Cd₁₀Se₄(SePh)₁₂(PnPr₃)₄] are reported leading to the identification of the doubly negatively charged species [Cd₁₇Se₄(SePh)₂₈]²⁻. Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) has been successfully applied to analyse the composition of a polycrystalline precipitate after treatment with SePh⁻ in tetrahydrofuran (THF). Presumably, SePh⁻ reacts with the insoluble (polymeric) cluster product as a charging ligand leading to dissolved monomeric units of the cluster anion [Cd₁₇Se₄(SePh)₂₈]²⁻. This cluster anion could also be crystallized from solutions as [Na(thf)₂18-crown-6][Cd₁₇Se₄(SePh)₂₈] and [Na(dme)₃]₂[Cd₁₇Se₄(SePh)₂₈]. The experimental results promise a wider applicability of the charged ligand exchange method for the electrospray mass spectrometric characterization of neutral clusters and to obtain intensive monodisperse cluster ion beams for further gas-phase studies. Dedicated to Prof. Dieter Fenske on the occasion of his 65th birthday.     

Free electron model in cluster structure theory. Electronic structures of [Mo6S8(CN)6]6?, [Mo6Se8(CN)6]6?, [Re6S8(CN)6]4?, and Rh6(CO)16 clusters

The results of quantum chemical calculations of the electronic structure and geometry of octahedral clusters [Mo₆S₈(CN)₆]⁶⁻, [Mo₆Se₈(CN)₆]⁶⁻, [Re₆S₈(CN)₆]⁴⁻, and Rh₆(CO)₁₆ by the ab initio SCF (RHF) and DFT (B3LYP) methods with various basis sets are presented. The electronic states of the clusters under study in ideal spherically symmetric potential were classified in the orbital quantum number l (1s, 1p, 1d, 1f, 1g, 1h, 1i), l = 0–6. In real crystal field with O_h symmetry these states are split. The calculated new electronic states were matched to the irreducible representations of the point symmetry group O_h. The polarizabilities of the compounds considered are 55–65 ų. A new model for the electronic structure of octahedral clusters containing M₆ groups was proposed. The model is based on the idea of free electrons moving in spherically symmetric potential field. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2617–2624, December, 2005.     

Aggregates of complexes [Sc(H2O)4(NCS)2]+ and [Sc(H2O)2(NCS)4]? with 18-crown-6

The compounds [Sc(H₂O)₄(NCS)₂][Sc(H₂O)₂(NCS)₄] ·2(18C6) (I) and [Sc(H₂O)₄(NCS)₂][Sc(H₂O)₂(NCS)₄] · 3(18C6) · H₂O (II) were synthesized and studied by X-ray diffraction analysis. It was found that the cations in the structures of compounds I and II form sandwiches [Sc(H₂O)₄(NCS)₂] · 2(18C6). In the case of I, the sandwiches are united by the [Sc(H₂O)₂(NCS)₄]⁻ anions into chains, while in compound II, the sandwiches and infinite chains of [Sc(H₂O)₂(NCS)₄] · 18C6 · H₂O are bonded by van der Waals contacts only. Original Russian Text ? A.B. Ilyukhin, S.P. Petrosyants, 2007, published in Koordinatsionnaya Khimiya, 2007, Vol. 33, No. 4, pp. 275–281.     

Synthesis, structural characterization, and magnetic properties of the metallamacrocycle [Fe6(C11H11N2O3)6(C4H9NO)6]

Abstract  

The 18-metallacrown-6 metallamacrocycle [Fe₆(pmshz)₆(C₄H₉NO)₆] has been synthesized by the self-assembly reaction of iron ions with N-substituted salicylhydrazide ligands. Six Fe(III) ions and six deprotonated N-propanoyl-4-methylsalicylhydrazide (H₃ pmshz) ligands construct a planar 18-membered ring based on Fe–N–N–Fe linkage. Because of the coordination, the ligand enforces the stereochemistry of the Fe(III) ions as a propeller shape with alternating …ΔΛΔΛ… configurations. There is a strong antiferromagnetic exchange interaction between the paramagnetic iron centers.     

Preparation, Thermal Behaviour, and Crystal Structure of MgAl2F8(H2O)2

 Single crystals of MgAl₂F₈(H₂O)₂ have been obtained under hydrothermal conditions (250°C, 14 d) from a starting mixture of AlF₃ and MgAlF₅(H₂O)₂ in a 5% (w/w) HF solution. The crystal structure has been determined and refined from single crystal data (Fmmm (#69), Z = 4, a = 7.2691(7), b = 7.0954(16), c = 12.452(2) ?, 281 structure factors, 27 parameters, R(F ² > 2σ (F ²)) = 0.0282, wR(F ² all) = 0.0885). The obtained crystals were systematically twinned according to (010/100/001) as twinning matrix, reflecting the pseudo-tetragonal metric. The crystal structure is composed of perowskite-type layers built of corner sharing AlF₆ octahedra with an overall composition of AlF₄ ⁻ which are connected via common fluorine atoms of [MgF_4/2(H₂O)_2/1] octahedra. Group-subgroup relations of MgAl₂F₈(H₂O)₂ to WO₃(H₂O)_0.33 and to other M(II)M(III)₂ F₈(H₂O)₂ structures are briefly discussed. Above 570°C, MgAl₂F₈(H₂O)₂ decomposes under elimination of water into α-AlF₃, β-AlF₃, and MgF₂.     

Synthesis, crystal structure and magnetic properties of the open framework compound Co3Te2O2(PO4)2(OH)4

The new compound Co₃Te₂O₂(PO₄)₂(OH)₄ was synthesized using hydrothermal techniques. It crystallizes in the monoclinic space group C2/m with the unit cell a=19.4317(10) Å, b=6.0249(3) Å, c=4.7788(2) Å, β=103.139(5)°. The crystal structure is an open framework having chains of edge sharing [Co(1)O₆] octahedra. Other building blocks are [TeO₃(OH)₂], [PO₄] and [Co(₂)O₂(OH)₄] connected mainly via corner sharing. The –OH groups protrude into channels in the structure. The magnetic susceptibility measured from 2 to 300 K shows two broad anomalies at around 21 K and 4 K, respectively. The peak at ∼20 K is ascribed to a two-dimensional antiferromagnetic ordering of linear [Co(1)O₆] chains coupled by interchain interaction via [PO₄] groups in the Co(1) sheets. The second transition at 4 K is ascribed to a second antiferromagnetic ordering of the moments of the Co(2) entities via super–super exchange involving [PO₄] and [TeO₃(OH)₂] groups. This assignment is strongly supported by low-temperature heat capacity measurements indicating an entropy removal within the high-temperature transition of about twice the magnitude of the low-temperature transition.     

Synthesis, structural characterization and properties of a 3D infinitely extended structural rare earth coordination compound of K3{[Sm(H2O)7]2Na[α-SiW11O39Sm(H2O)4]2} · 14 H2O· 14 H2O

A 3D infinitely extended structural rare earth coordination compound with a formula of K₃{[Sm(H₂O)₇]₂Na[α-SiW₁₁O₃₉Sm(H₂O)₄]₂}·14H₂O has been synthesized by reaction of Sm₂O₃, HClO₄, NaOH with α-K₈SiW₁₁O39·nH₂O, and characterized by IR, UV spectra, ICP, TG-DTA, cyclic voltammetry, variable-temperature magnetic susceptibility and X-ray single-crystal diffraction. X-ray single-crystal diffraction indicates that the title compound crystallizes in a triclinic lattice, Pī space group, with a = 1.2462(3) nm, b = 1.2652(3) nm, c = 1.8420(4) nm, α = 87.45(3)°, β = 79.91(3)°, γ= 82.57(3)°, Z = 1, R₁ = 0.0778, wR₂ = 0.1610. Structural analysis reveals that Sm³⁺(1) coordination cation has incorporated into the vacant site of [α-SiW11O₃₉]⁸⁻ entity, forming the [α- SiW₁₁O₃₉Sm(H₂O)₄]⁵⁻ subunit. The two adjacent [α-SiW₁₁O₃9Sm(H₂O)4]⁵⁻ subunits are combined with each other through two Sm(1)-O-W bridges accompanying the formation of dimmer structural unit [α-SiW₁₁O₃₉Sm(H₂O)₄]₂ ¹⁰⁻ of the title compound. The neighboring dimmer structural units [α-SiW₁₁O₃₉Sm(H₂O)₄]₂ ¹⁰⁻ are linked to form the 1D chainlike structure by means of two Sm³⁺(2) and a Na⁺(1) coordination cations. The K⁺(1) cations connect the 1D packing chains constructing the 2D netlike structure, and adjacent netlike layers are also grafted by K⁺(2) cations to build the novel 3D infinitely extended structure. The result of TG-DTA curves manifests that the decomposition temperature of the title polyanionic framework is 554°C. The cyclic voltammetry measurements show that the title polyanion has the two-step redox processes in aqueous solution with pH = 3.1. Variable temperature magnetic susceptibility indicates the title compound obeys the Cruie-Weiss Law in the higher temperature range from 110 to 300 K, while in the lower temperature range from 2 to 110 K the comparatively strong antiferromagnetism interactions can be observed.     

New Selenidogermanates with Transition-Metal Complexes as Counterions: Solvothermal Synthesis, Crystal Structures, and Properties of [Mn(en)3]2Ge2Se6 and [Fe(dien)2]2Ge2Se6

Summary. New selenidogermanates [Mn(en)₃]₂Ge₂Se₆ (en = ethylenediamine) and [Fe(dien)₂]₂Ge₂Se₆ (dien= diethylenetriamine) were synthesized by the reaction of germanium dioxide, elemental selenium, and transition metal chlorides in respectively en and dien. Both compounds crystallize in the monoclinic space group P2₁/n with two formula units in the unit cell, and consist of discrete [Ge₂Se₆]⁴⁻ anions with transition metal complex cations as counter ions. The [Ge₂Se₆]⁴⁻ anion is formed by two GeSe₄ tetrahedra sharing a common edge to form a planar Ge₂Se₂ four-membered ring. The [Mn(en)₃]²⁺ and [Ni(dien)₂]²⁺ complex cations are in distorted octahedral geometry. In both selenidogermanates extensive N–H···Se hydrogen bonding contacts lead to 3-dimensional network structures. The band gaps of 2.36 and 2.25 eV were derived from optical absorption spectra. Thermogravimetric analysis shows that the first compound decomposes in two steps under the nitrogen stream, while the second exhibits a one-step decomposition process.     

Crystal structure of cadmium iodide complexes with acetamide and propaneamide [Cd(CH3CONH2)6][Cd2I6] and [Cd(C2H5CONH2)6][Cd2I6]

The complexes of CdI₂ with acetamide (AA) and propaneamide (PrA) of the composition [Cd(AA)₆][Cd₂I₆] (I) and [Cd(PrA)₆][Cd₂I₆] (II) were synthesized and studied by X-ray diffraction. Isostructural crystals I and II are triclinic: a = 7.285(3) and 8.066(6), b = 11.266(4) and 11.649(3), c = 11.554(3) and 12.063(2) ?, α = 100.96(2)° and 102.74(2)°, β = 91.59(2)° and 91.73(4)°, γ = 100.76(3)° and 101.05(4)°, V = 912.5 and 1081.9 ?³, respectively; space group , Z = 1. Original Russian Text ? I.A. Zamilatskov, E.V. Savinkina, D.V. Al’bov, 2007, published in Koordinatsionnaya Khimiya, 2007, Vol. 33, No. 6, pp. 407–410.     

The standard enthalpy of formation of (XeF5)2[MnF6](cr)

The enthalpies of interaction of (XeF₅)₂[MnF₆](cr) with a 0.0524 m solution of KOH and a 0.0300 m solution of H₂SO₄, the enthalpy of solution of KMnO₄(cr) in a 0.0440 m solution of KOH, and the enthalpy of mixing of aqueous KF with alkaline KMnO₄ were measured in isothermic-shell calorimeters at 298.15 K. The standard enthalpy of formation of the compound at 298.15 K was calculated by two independent procedures using the experimental values and literature data (Δ_f H ^o = −1185 ± 18 kJ/mol). Original Russian Text ? S.N. Solov’yov, A.A. Firer, A.Ya. Dupal, 2009, published in Zhurnal Fizicheskoi Khimii, 2009, Vol. 83, No. 4, pp. 798–800.