SYNTHESIS OF A DINUCLEAR YLID COMPLEX DERIVED FROM P(OPh)3: CRYSTAL STRUCTURES OF [Cp2Fe2(CO)2(μ-CO) (μ-CHP(OPh)3)+][BF4 −] AND [Cp2Fe2(CO)2 (μ-CO)(μ-CHPPh3)+][BF4 −]

Abstract

[Cp₂Fe₂(CO)₂(μ-CO)(μ-CHP(OPh)₃)⁺][BF^? ₄] crystallizes in the centrosymmetric monoclinic space group P2₁/n with a = 12.553(7) Å, b = 16.572(11) Å, c = 15.112(8) Å, β = 100.00(4)°, V = 3096(3) ų and D(calcd.) = 1.579 g/cm³ for Z = 4. The structure was refined to R(F) = 5.83% for 1972 reflections above 4σ(F). The cation contains two CpFe(CO) fragments linked via an iron—iron bond (Fe(1)—Fe(2) = 2.544(3)Å), a bridging carbonyl ligand (Fe(1)—C(4) = 1.918(1) Å, Fe(2)—C(4) = 1.946(12)Å) and a bridging CHP(OPh)₃ ligand (Fe(1)—C(1) = 1.980(9)Å, Fe(2)—C(1) = 1.989(8)Å). Distances within the μ-CHP(OPh)₃ moiety include a rather short carbon—phosphorus bond [C(1)—P(1) = 1.680(10)Å] and P—O bond lengths of 1.550(7)–1.579(6)Å. The crystal is stabilized by a network of F…H—C interactions involving the BF^? ₄ anion.

[Cp₂Fe₂(CO)₂(μ-CO)(μ-CHPPh₃)⁺][BF^? ₄], which differs from the previous compound only in having a μ-CHPPh₃ (rather than μ-CHP(OPh)₃) ligand, crystallizes in the centrosymmetric monoclinic space group P2₁/c with a = 11.248(5)Å, b = 13.855(5)Å, c = 18.920(7)Å, β = 96.25(3)°, V = 2931(2)ų and D(calcd.) = 1.559 g/cm³ for Z = 4. This structure was refined to R(F) = 4.66% for 1985 reflections above 4σ(F). Bond lengths within the dinuclear cation here include Fe(1)-Fe(2) = 2.529(2)Å, Fe(1)—C(3) = 1.904(9) Å and Fe(2)—C(3) = 1.911(8) Å (for the bridging CO ligand) and Fe(1)—C(1P) = 1.995(6) Å and Fe(2)—C(1P) = 1.981(7) Å (for the bridging CHPPh₃ ligand). Distances within the μ-CHPPh₃ ligand include a longer carbon—phosphorus bond [C(1P)—P(1) = 1.768(6)Å] and P(1)—C(phenyl) = 1.797(7)–1.815(8) Å.     

Synthesis,crystal structure,magnetic property,and nuclease activity of a binuclear iron(III) complex

A μ-oxo-di-μ-carboxylato-bridged iron(III) complex containing two tridentate nitrogen ligands, {[Fe₂(bpma)(bpea)(μ-CH₃COO)₂ μ-O)] · (ClO₄)₂ · 0.5CH₃OH} (1) (bpma = N, N-bis(2-pyridylmethyl)methyl-amine, bpea = N,N-bis(2-pyridylmethyl)ethylamine), has been synthesized and determined by X-ray diffraction. Complex 1 crystallizes in the monoclinic space group P2₁/c with a = 10.9434(12) Å, b = 23.118(3) Å, c = 15.8721(18) Å, β = 92.736(2)° and Z = 4. In 1, each Fe(III) has a distorted octahedral geometry with a N₃O₃ donor set. The Fe(III) atoms are bridged by two carboxyl groups and one μ-oxo oxygen with Fe1–Fe2 separation of 3.064 Å. Susceptibility data of 1 indicate strong intramolecular antiferromagnetic coupling of the high-spin Fe(III) atoms with J = ?121.0 cm^?1 and g = 2.04. The interaction with calf thymus DNA was investigated by UV absorption and fluorescent spectroscopy. Results show that the complex binds to ct-DNA with a moderate intercalative mode. The interaction between 1 and pBR322 DNA has also been investigated by submarine gel electrophoresis; the complex exhibits effective DNA cleavage activity in the absence of activating agents under similar physiological conditions.     

Crystal structure and thermal stability of A μ1,1-(OMe)-bridged dimeric Schiff base iron(III) complex

A new μ_1,1-OMe-bridged dimeric iron(III) complex, [Fe₂L₂(μ_1,1-OMe)₂(NCS)₂], where L is the deprotonated form of 2-[(2-ethylaminoethylimino)methyl]-5-methoxyphenol, has been prepared and structural characterized by elemental analysis, IR spectrum, and single crystal X-ray crystallography. The complex crystallizes in the monoclinic space group P2₁/c, with unit cell dimensions a = 10.156(1) Å, b = 11.972(1) Å, c = 14.256(2) Å, β = 102.643(3)°, V = 1691.3(3) ų, Z = 2, R ₁ = 0.0394, and wR ₂ = 0.0922. Each Fe atom in the complex is in an octahedral coordination. The Fe...Fe distance is 3.102(1) Å. The thermal stability of the complex was studied.     

Exploring Route for Pyrophosphate-based Electrode Materials: Interplay between Synthesis and Structure

New sodium vanadium(III) hydrogenphosphate hydrate NaV(HPO₄)₂(H₂O)_0.5 and sodium vanadium(III) hydrogenphosphate β-NaV(HPO₄)₂ were prepared in mild hydrothermal conditions. The crystal structures of NaV(HPO₄)₂(H₂O)_0.5 [space group Cc, Z = 4, a = 8.46174(19) Å, b = 9.52583(19) Å, c = 8.69376(15) Å, β = 110.9553(11) °, V = 654.41(2) ų] and β-NaV(HPO₄)₂ [space group C2/c, Z = 4, a = 7.8681(3) Å, b = 9.8451(3) Å, c = 8.5180(2) Å, β = 107.626(2) °, V = 628.85(3) ų] were solved and refined from X-ray powder diffraction data. Both compounds were used as precursors in a new route for the preparation of attractive cathode material β-NaVP₂O₇. The formation of the structure motive providing fast sodium ion diffusion at the first synthesis stage and its further conservation upon stepwise dehydration was revealed. The oversized Na⁺-embedding channels are stabilized by site-coordinated water in NaV(HPO₄)₂(H₂O)_0.5 structure. The topology resemblance and difference in known sodium vanadium(III) complex phosphates are discussed.     

Synthesis,magnetic property and DNA cleavage behavior of a new dialkoxo‐bridged diiron(III) complex

A new dialkoxo‐bridged diiron(III) complex, [Fe₂(BMA)₂(CH₃O)₂Cl₂]·2Cl·4CH₃OH ( 1 ) [BMA = N,N‐bis(2‐benzimidazolylmethyl)amine], was synthesized and characterized by UV‐visible absorption and infrared spectra and magnetic susceptibilities. The complex crystallizes in the monoclinic system, space group P2(1)/n, a = 12.9659(19) Å, b = 10.0278(16) Å, c = 17.919(2) Å, β = 93.766(8)° , V = 2324.8(6) ų, Z = 2, F(000) = 1036, D_c = 1.426 g cm^?3, µ = 0.908 mm^?1. According to X‐ray crystallographic studies, each Fe(III) ion lies in a highly distorted octahedral environment, and two Fe(III) ions are bridged by the methoxyl oxygens. Cryomagnetic analyses indicated a moderate antiferromagnetic interaction between the high‐spin Fe(III) ions, with J = ? 27.05 cm^?1. Moreover, the binding interaction of DNA with the diiron complex was investigated by spectroscopic and agarose gel electrophoretic methods, showing moderate cleavage activity on pBR322 plasmid DNA at physiological pH and temperature. Copyright © 2007 John Wiley & Sons, Ltd.     

Crystal structure of Pb<Subscript>2</Subscript>[Fe(CN)<Subscript>6</Subscript>]NO<Superscript>3</Superscript>·5.5H<Subscript>2</Subscript>O

Synthesis of a mixed complex compound Pb₂[Fe(CN)₆]NO₃·5.5H₂O is described. The results of its X-ray structural investigation are presented. Crystal data: C₆H₁₁FeN₇O_8.50Pb₂: a = 7.2582(6) Å, b = 21.838(3) Å, c = 11.612(1) Å; β = 107.91(1)°, V = 1751.4(3) ų, Z = 4, d_calc = 2.986 g/cm³, space group P2₁/m, R = 0.038. The compound has a framework polymer structure.     

Structure of cyano-bridged Eu(III)—Co(III) bimetallic assembly and its application to photophysical verification of photomagnetic phenomenon

New crystal structure of Eu(DMF)₄(H₂O)₃Co(CN)₆·H₂O (DMF = N,N′-dimethylformamide) (Eu-Co) has been determined to be monoclinic, P2(1)/n, a = 19.796(12) Å, b = 8.862(11) Å, c = 17.525(10) Å, β = 96.26(5)°, V = 3056(5) ų, Z = 4. The Eu(III) ion adopts an antiprismatic eight-coordination and forms a cyano bridge with r(Eu-N) = 2.496(7) Å and Θ(Eu-N-C) = 165.7(7)° to the Co(III) ion. The complex exhibits some common features with the Eu-Fe complex. Diffuse reflectance electronic spectra and magnetic susceptibility of Eu-Cr, Eu-Mn, Eu-Fe, and Eu-Co complexes were compared. By substituting the metal ions, both electronic and structural features affected the charge transfer bands and superexchange interactions concerning cyanide ligands. In addition, only Eu-Co exhibited ⁵ D ₀ → ⁷ F ₂ and ⁵ D ₀ → ⁷ F ₁ luminescence bands at 16300 cm^?1 and 16900 cm^?1, respectively at 298 K (λ_ex = 360 nm (27000 cm^?1)), because quenching by cyano-bridged ions did not prevent Eu(III) ion from exhibiting emission. Thus, only Eu-Co may be suitable for verification of an assumption of mechanism concerning drastic photoinduced magnetic changes for Nd-Fe. Merely small decrease of magnetization was observed for Eu-Co after UV light irradiation at 2.0 K. This result was attributed to slight structural changes around cyano bridges without transitions of spin states.     

Crystal structure and luminescence of europium(III) acrylate

The atomic structure of europium acrylate crystals [Eu₂(Acr)₅OH·3H₂O]·2(0.5H₂O) was studied by X-ray analysis (a = 24.360(3) Å, b = 18.466(2) Å, c = 8.5818(9) Å, β = 96.087(2)°, space group C2/c, Z = 6, ρ_calc = 2.036 g/cm³). The crystal structure involves chains of binuclear [Eu₂(C₃H₃O₂)₅OH·3H₂O] molecules, running infinitely in the [101] direction and having pairs of C₉H₉EuO₇H₂O molecules alternating with C₆H₆EuO₄OH·2H₂O molecules that link the pairs. The infinite chains are linked by hydrogen bonds and van der Waals interactions. The thermal behavior of luminescence of the europium(III) complex is discussed.     

Kristallstrukturen und Schwingungsspektren von Tetrahalogenoacetylacetonatoosmaten(IV), [OsX4(acac)]−, X  Cl,Br, I

Crystal Structures and Vibrational Spectra of Tetrahalogenoacetylacetonatoosmates(IV), [OsX₄(acac)]^?, X ? Cl, Br, I By reaction of the hexahalogenoosmates(IV) with acetylacetone the tetrahalogenoacetylacetonatoosmates(IV) [OsX₄(acac)]^? (X = Cl, Br, I) are formed, which have been purified by chromatography and precipitated from aqueous solution as tetraphenylphosphonium (Ph₄P) or cesium salts. X-ray structure determinations on single crystals have been performed of (Ph₄P)[OsCl₄(acac)] ( 1 ) (triclinic, space group P1 , a = 9.9661(6), b = 11.208(2), c = 13.4943(7) Å, α = 101.130(9), β = 91.948(6), γ = 96.348(8)°, Z = 2), (Ph₄P)[OsBr₄(acac)] ( 2 ) (monoclinic, space group P2₁/n, a = 9.0251(8), b = 12.423(2), c = 27.834(2) Å, β = 94.259(7)°, Z = 4) and (Ph₄P)[OsI₄(acac)] ( 3 ) (monoclinic, space group P2₁/c, a = 18.294(3), b = 10.664(2), c = 18.333(3) Å, β = 117.68(2)°, Z = 4). Due to the increasing trans influence in the series O < Cl < Br < I the Os? O^. distances of O^.? Cl? X′ axes are lengthened and the OsO^. stretching vibrations are shifted to lower frequencies. The Os? X′ bond lenghts are shorter as compared with symmetrically coordinated X? Os? X axes.     

Fragmentation reactions ofN-sulfinylaniline PhNSO by the dinuclear complex [Fe2(CO)7{μ-C(R)C(NEt2)}]: Nitrene and sulfur insertions into iron carbene bonds. Synthesis and x-ray structures of [Fe2(CO)6{μ-N(Ph)C(NEt2)C(Me)S}] [Fe2(CO)6{μ-N(Ph)C(NEt2)C(Ph)S}] · 0.5C6H14 and [Fe2(CO)6{μ-C(C3H5)C(NEt2)N(Ph)SO}] · 0.5CH2Cl2

The diiron ynamine complexes [Fe₂(CO)₇{μ-C(R)C(NEt₂)}] (1) (R=Me, Ph, C₃H₅, SiMe₃) react with theN-sulfinylaniline, PhNSO, in refluxing hexane to yield the complexes [Fe₂(CO)₆{μ-N(Ph)C(Me)S}] (2), [Fe₂(CO)₆{μ-N(Ph)C(NEt₂)C(Ph)S}] · 0.5C₆H₁₂ (3), [Fe₂(CO)₆{μ-C(C₃H₅)C(NEt₂)N(Ph)SO}] · 0.5CH₂Cl₂ (4), and [Fe₂(CO)₆{μ-C(SiMe₃)C(NEt₂)S)}] (5). Compound 5 was found to be identical to the previously reported product obtained from the reaction of 1 with sulfur. Compounds 2, 3, and 4 were characterized by single crystal X-ray diffraction analyses. Crystal data: for 2: space group = P2₁/n,a=9.533(1) Å,b=18.830(4) Å,c=12.705(4) Å, β=107.01(2)°,Z=4, 2687 reflections,R=0.027; for 3: space group=P2₁/n,a=13.660(2) Å,b=19.096(8) Å,c=10.972(2) Å, β=90.62(1)°,Z=4, 2821 reflections,R=0.036; for 4: space group=P2₁/a,a=18.098(5) Å,b=16.564(4) Å,c=18.548(2) Å, β=115.44(2)°,Z=4, 3569 reflections,R=0.041. Complexes 2 and 3 result from fragmentation of theN-sulfinylaniline ligand and insertion of the nitrene grouping into the Fe=C(aminocarbene) bond, whereas the sulfur atom inserts into one Fe-C bond of the bridging carbene. Compound 4 is formed by insertion of the entireN-sulfinyl aniline ligand into the Fe=C(aminocarbene) bond. All three complexes have basket-like arachno structure isolobal to the benzvalene one.     

Synthesis and structures of polyiodide acetamide complexes of transition metals

Polyiodides of acetamide complexes of transition elements have been synthesized and studied by X-ray diffraction analysis. Compounds [M(AA)₆][I₁₀] (M = Mn, Fe, Co, Ni, Zn) are isostructural with the earlier studied cadmium compound. The crystals of [Co(AA)₄(H₂O)₂][I₁₂] are monoclinic: a = 17.486(6) Å, b = 15.015(4) Å, c = 7.8309(15) Å, β = 99.87(2)°, V = 2025.6(10) ų, space group C2/m, Z = 4. The crystals of [Ni(AA)₆][I₃]₂ are monoclinic: a = 23.032(9) Å, b = 12.176(4) Å, c = 18.274(5) Å, β = 139.22(3)°, V = 3347.0(19) ų, space group Cc, Z = 4.     

Nine-coordinate rare earth metal complexes with aminopolycarboxylic acids: Mononuclear (NH4)3[TbIII(ttha)]·5H2O and binuclear (NH4)4[Tb 2 III (dtpa)2]·9H2O

The two title coordination compounds, (NH₄)₃[Tb^III(ttha)]·5H₂O (ttha = triethylenetetramine-N,N,N′,N″,N‴,N‴-hexaacetic acid) and (NH₄)₄[Tb ₂ ^III (ttha)]·9H₂O (dtpa = diethylenetriamine-N,N,N′,N″,N″-pentaacetic acid), have been prepared and characterized by FT-IR, elemental analyses, TG-DTA and single crystal X-ray diffraction techniques. The (NH₄)₃[Tb^III(ttha)]·5H₂O compound is monoclinic, P2₁/c; a = 10.398(1) Å, b = 12.791(1) Å, c = 23.199(2) Å; β = 90.914(2)°; V = 3084.9(5) ų; Z = 4; D _calc = 1.704 g/cm³; μ(MoK _α ) = 2.376 mm^™; R = 0.023 and wR ² = 0.049 for 5429 observed reflections with I ≥ 2σ(I). The [Tb^III(ttha)]³⁻ complex anion in the crystal has a nine-coordinate mononuclear molecular structure with pseudo-monocapped square-antiprismatic configuration. The (NH₄)₄[Tb ₂ ^III (dtpa)₂]·9H₂O compound is triclinic, P-1; a = 9.739(1) Å, b = 10.010(1) Å, c = 12.968(2) Å; α= 85.890(2)°, β = 77.338(2)°, γ = 77.587(2)°; V = 1204.2(2) ų; Z = 1; D _calc = 1.832 g/cm³; μ(MoK _α ) = 3.015 mm^™; R = 0.024 and wR ² = 0.060 for 4750 observed reflections with I ≥ 2σ(I). The [Tb ₂ ^III (dtpa)₂]₄₋ complex anion has a binuclear structure in the crystal; the two Tb^III centers are equivalent and have a nine-coordinate environment with the same pseudo-tricapped trigonal-prismatic configuration. The thermal analysis revealed that the coordination cores of the (NH₄)₃[Tb^III(ttha)]·5H₂O and (NH₄)₄[Tb ₂ ^III (dtpa)₂]·9H₂O compounds are stable up to 221°C and 252°C, respectively. Original Russian Text Copyright ? 2008 by J. Wang, X. Zh. Liu, X. F. Wang, G. R. Gao, Zh. Q. Xing, X. D. Zhang, and R. Xu The text was submitted by the authors in English. Zhurnal Strukturnoi Khimii, Vol. 49, No. 1, pp. 81–89, January–February, 2008.     

Reaction of iron pentacarbonyl with N,N-diethyl-S-ethylcarbamate; crystal structure of [{Fe(CO)6}3(μ4-S)2(μ-CNEt2)2]3(feFe), a compound containing three butterfly units

Reaction of iron pentacarboynl with N,N-diethyl-S-ethylcarbamate {SC-(NEt₂)SEt} gave [{Fe₂(CO)₆}{Fe₃(CO)₉(μ₄-S)(μ-CNEt₂(μ-SEt)}](FeFe)3-(FeFe) (I) and [{Fe₂(CO)₆}₃(μ₄-S)₂(μ-CNEt₂3(FeFe) (II). The structure of complex II has been determined by single crystal X-ray crystallography. It crystallizes from methylene chloride as C₂₆H₂₀O₁₈N₂S₂Fe₆·1/2CH₂Cl₂ in the monoclinic space group C2/c with a 46.754(2), b 9.268(1), c 19.628(2) Å, β 100.7(1)°, Z = 8, V 8358.6 ų, D_c 1.77 g cm⁻³, D_m 1.77 gm cm⁻³. The strucutre was solved by direct methods and refined to R = 0.0819 (R_w = 0.0469) for 3017 relfections. It consists of three metalmetal bonded Fe₂(CO)₆ units linearly linked in butterfly configuration by two bridging sulphur athoms, and terminated on both sides by bridging diethylimoniocarbene (CNEt₂) ligands.     

Darstellung der Halogeno-Pyridin-Rhenate(III), [ReX6−n (Py)n](3−n)− (X = Br,Cl; n = 1−3), sowie Kristallstrukturen von trans-[(C4H9)4N][ReBr4(Py)2], mer-[ReCl3(Py)3] und mer-[ReBr3(Py)3]

Preparation of Halogeno Pyridine Rhenates(III), [ReX_6?n(Py)_n]^(3?n)? (X = Br, Cl; n = 1?3) Crystal Structures of trans-[(C₄H₉)₄N][ReBr₄(Py)₂], mer-[ReCl₃(Py)₃], and mer- [ReBr₃(Py)₃] The mixed halogeno-pyridine-rhenates(III), [ReX_6?n(Py)_n]^(3?n)? (X = Br, Cl), n = 1?3, have been prepared for the first time by reaction of the tetrabutylammoniumsalts (TBA)₂[ReX₆] (X = Br, Cl) in pyridine with (TBA)BH₄ and separation by chromatography on Al₂O₃. Apart from the monopyridine complexes only the trans and mer isomers are formed from the bis-and tris-pyridine compounds. The X-ray structure determinations of the isotypic neutral complexes mer- [ReX₃(Py)₃] (monoclinic, space group P 2₁/n, Z = 4; for X = Cl: a = 9,1120(8), b = 12,5156(14), c = 15,6100(13) Å, β = 91,385(7)°; for X = Br: a = 9,152(5), b = 12,852(13), c = 15,669(2) Å, β = 90,43(2)°) reveal, due to the stronger trans influence of pyridine compared with Cl and Br, that the Re? X distances in asymmetric Py? Re? X3 axes with ReCl3 = 2,397 Å and ReBr3 = 2,534 Å are elongated by 1,3 and 1% in comparison with symmetric X1? Re? X2 axes with ReCl1 = ReCl2 = 2,367 Å and ReBr1 = 2,513 and ReBr2 = 2,506 Å, respectively. The Re? N bond lengths are roughly equal with 2,12 Å. Trans-(TBA)[ReBr₄(Py)₂] crystallizes triclinic, space group P1 , a = 9,2048(12), b = 12,0792(11), c = 15,525(2) Å, α = 95,239(10), β = 94,193(11), γ = 106,153(9)°, Z = 2. The unit cell contains two independent but very similar complex anions with approximate D_2h(mmm) point symmetry.     

Homo‐ and Heteropentanuclear Coordination Compounds with Td Symmetry – the Solid State Structures of [MZn4(L)4(L′)6] (M = CoII or Zn; L = chloride or acac; L′ = 1,2,3‐benzotriazolate)

The syntheses of homo‐ and heteropentanuclear coordination compounds with the molecular formulae [MZn₄(L)₄(L′)₆] (M = Co^II or Zn; L = chloride or acac; L′ = 1,2,3‐benzotriazolate) are reported. These compounds display a highly symmetric coordination unit consisting of a central metal ion (M = Co^II or Zn) which is octahedrally coordinated by 6 tridentate benzotriazolate‐type ligands via their N(2) donor atom. The benzotriazolate ligands span the edges of an imaginary tetrahedron thus providing four coordination sites at the corners of the tetrahedron, which are then filled by four zinc ions. The coordination shell of the latter are completed by bidentate acetylacetonate (acac) ligands or by chloride anions, respectively. The solid state structures of two homopentanuclear metal complexes, namely [Zn₅(acac)₄(bta)₆]·4C₆H₁₂ ( 1 ) (acacH = acetylacetone; btaH = 1,2,3‐benzotriazole), and [Zn₅Cl₄(Me₂bta)₆]·2DMF ( 2 ) (Me₂btaH = 5,6‐dimethyl‐1,2,3‐benzotriazole) were determined by single crystal X‐ray structure analysis. The heteropentanuclear metal complex [Co^IIZn₄Cl₄(Me₂bta)₆]·2DMF ( 3 ) is isostructural with compound 2 . Compound 1 was synthesized from stoichiometric amounts of Zn(acac)₂ and btaH employing dichloromethane as solvent. The synthesis of compound 2 requires addition of an auxiliary base to the DMF solution of anhydrous ZnCl₂ and Me₂btaH. For compound 3 a stoichiometric ratio of Co(NO₃)₂·6H₂O, anhydrous ZnCl₂ and Me₂btaH was employed during synthesis. Phase purity of all compounds was proved by X‐ray powder diffraction (XRPD) analysis, IR spectroscopy, and elemental analysis. Crystal data: for 1 (C₈₀H₁₀₀N₁₈O₈Zn₅): monoclinic, space group P2₁/c with a = 23.781(5) Å, b = 16.000(3) Å, c = 25.170(5) Å, β = 115.29(3)°, V = 8659(3) ų, Z = 4, ρ = 1.357 g cm^?3. For 2 (C₅₄H₆₂Cl₄N₂₀O₂Zn₅): cubic, space group with a = 23.367(3) Å, V = 12759(3) ų, Z = 8, ρ = 1.553 g cm^?3. For 3 (C₅₄H₆₂Cl₄CoN₂₀O₂Zn₄): cubic, space group with a = 23.443(3) Å, V = 12884(3) ų, Z = 8, ρ = 1.532 g cm^?3.     

Détermination de la structure cristalline du ferrite de baryum Ba2Fe6O11

The crystal structure of dibarium triferrite Ba₂Fe₆O₁₁ has been solved by direct methods, using intensity data collected by means of an automated diffractometer (MoKα radiation) and corrected for absorption. It crystallizes in the orthorhombic space group Pnnm: a = 23.024(10)Å, b = 5.181(3) Å, c = 8.900(4) Å, Z = 4. Program MULTAN was successfully used for locating Ba²⁺ and most of the Fe³⁺ ions. The structure was further refined by conventional Fourier and least-squares methods (full-matrix program) to a final R value of 0.045 for 1448 observed reflections. Fe³⁺ ions occur in both octahedral (FeO mean distance: 2.02 Å) and tetrahedral (FeO mean distance: 1.865 Å) coordination. Two types of Ba²⁺ ions are found, with six and seven neighboring oxygen atoms. The structure consists of sheets of edge-shared FeO₆ octahedra which are connected by means of corner-shared tetrahedra.     

Refinements of the six-layer structures of the R-type hexagonal ferrites BaTi2Fe4O11 and BaSn2Fe4O11

The structures of BaTi₂Fe₄O₁₁ and BaSn₂Fe₄O₁₁ have been determined from neutron powder diffraction data collected at 300 K using the Rietveld profile refinement. The compounds were found to be isostructural, space group $\text{P6}{}_3\text{mmc}$. BaTi₂Fe₄O₁₁: a = 5.8470(2) Å, c = 13.6116(9) Å, V = 403.01(5) ų, M = 632.6, Z = 2, D_calc. = 3.09 Mg m^?3, final R-factor = 3.77. BaSn₂Fe₄O₁₁: a = 5.9624(5) Å, c = 13.7468(14) Å, V = 423.23(10) ų, M = 774.2, Z = 2. D_calc. = 3.66 Mg m^?3, final R-factor = 2.41. The structure consists of h-stacked BaO₃ and O₄ layers in the ratio 1:2. The BaO₃ layers contain a mirror plane. Between the O₄ layers three octahedral sites are occupied, and between the BaO₃ and O₄ layers an octahedral site and a tetrahedral site are occupied. Because of the mirror plane in the BaO₃ plane the latter sites both share faces in the BaO₃ plane. The octahedral sites are occupied by Fe and Ti or Sn, the pair of tetrahedral sites is occupied by one Fe atom. This Fe atom may hop between these two tetrahedral sites. The structure is considered to be constructed by two R-blocks of the BaFe₁₂O₁₉ (M) structure. Unit-cell dimensions are given of a number of isostructural compounds of general formula A^IIB^IV₂C^III₃O₁₁. Mössbauer experiments on some of these compounds were focused on the tetrahedral positions that show an unusual quadrupole splitting. A brief review is given of the observed magnetic properties of some compounds with the R-structure.     

Synthesis and structure of CsLi0.5Al0.5PO4

A new phosphate CsLi_0.5Al_0.5PO₄ with a structure related to the β-tridymite structure has been synthesized by a precipitation method. X-ray powder diffraction, electron probe microanalysis, second harmonic generation of laser radiation, and IR spectroscopy have been used for studying the compound. Differential scanning calorimetry shows that the synthesized phosphate undergoes phase transitions at T _tr = 68 and 130°C. The crystal structure of CsLi_0.5Al_0.5PO₄ was refined on the basis of X-ray powder diffraction data by the Rietveld method in space group P2₁/a (Z = 8) with the unit cell parameters a = 17.8323(3) Å, b = 5.4250(1) Å, c = 9.3666(2) Å, β = 89.984(8)°, V = 906.10(9) ų.     

Crystal structure and luminescence of antimony(III) chloride complex with anilinium chloride

Crystal structure of (C₆H₅NH₃)₃[SbCl₅]Cl·H₂O is determined by X-ray analysis (a = 9.4155(13) Å, b = 11.4344(16) Å, c = 13.1584(18) Å, α = 113.483(2)°, β = 90.383(2)°, γ = 97.323(2)°, space group P \(\bar 1\), Z = 2, ρ_calc = 1.642 g/cm³). The crystal structure is based on [SbCl₅]^2? anions, anilinium cations (C₆H₅NH₃)⁺, isolated Cl^? anions, and water molecules. Structural features responsible for spectral and luminescent properties of the complex are discussed.     

New fluorochromatouranylates of alkali metals: Synthesis and structure

Four new fluorochromatouranylates, namely, K[UO₂(CrO₄)F] · 1.5H₂O (I), Rb[UO₂(CrO₄)F] · 1.5H₂O (II), Rb[UO₂(CrO₄)F] · 0.5H₂O (III), and Cs[UO₂(CrO₄)F] · 0.5H₂O (IV), have been synthesized, and their crystallographic characteristics have been determined. All the compounds crystallize in monoclinic system, space group P2₁/c, with the unit cell parameters a = 13.1744(5) Å, b = 9.4598(3) Å, c = 13.0710(4) Å, β = 103.746(1)°, Z = 4, R = 0.0235 (I); a = 13.5902(7) Å, b = 9.5022(4) Å, c = 13.2271(6) Å, β = 102.914(2)°, Z = 4, R = 0.0247 (II); a = 24.7724(8) Å, b = 12.6671(4) Å, c = 9.4464(3) Å, β = 97.661(1)°, Z = 8, R = 0.0448 (III); a = 25.725(1) Å, b = 12.8261(5) Å, c = 9.4929(4) β = 97.208(1)°, Z = 8 (IV). The pairs of compounds I and II and compounds III and IV are isostructural. Crystals of compounds I–III have been subjected to complete X-ray diffraction study. It has been established that the structures of compounds I–III are built of [UO₂(CrO₄)F] _n ^n? layers, which are parallel to the (100) plane and linked into a framework by alkali-metal cations located between layers, together with water molecules. The effect of topological and geometric isomerism on the structural features of 34 known uranyl compounds of the AT³M² crystallochemical group, to which the studied compounds I–III also belong, is discussed.