Synthesis and structure of K2[(UO2)4(O)2(OH)2(C2O4)(CH3COO)2(H2O)2]·2H2O

Single crystals of the compound K₂[(UO₂)₄(O)₂(OH)₂(C₂O₄)(CH₃COO)₂(H₂O)₂]·2H₂O (I) are synthesized, and their structure is investigated using X-ray diffraction. Crystals of compound I belong to the triclinic system with the unit cell parameters a = 7.6777(6) ?, b = 7.9149(7) ?, c = 10.8729(9) ?, α = 72.379(2)°, β = 86.430(3)°, γ = 87.635(2)°, V = 628.33(9) ?³, space group P , Z = 1, and R ₁ = 0.0323. The main structural units of the crystals are [(UO₂)₄(O)₂(OH)₂(C₂O₄)(CH₃COO)₂(H₂O)₂]²⁻ chains, which belong to the crystal-chemical group A ₄ M ₂³ M ₂² K ⁰² B ₂⁰¹ M ₂¹ (A = UO₂²⁺, M ³ = O²⁻, M ² = OH⁻, K ⁰² = C₂O₄²⁻, B ⁰¹ = CH₃COO⁻, M ¹ = H₂O) of the uranyl complexes. The chains are formed by linking the centrosymmetric tetramers of the composition (UO₂)₄(O)₂(OH)₂(CH₃COO)₂(H₂O)₂ via tetradentate bridging oxalate ions. The uranium-containing groups are joined into a three-dimensional framework through the electrostatic interaction with potassium cations and a system of hydrogen bonds, which are formed with the participation of atoms involved in the composition of the water molecules, hydroxide ions, and uranyl ions. Original Russian Text ? L.B. Serezhkina, A.V. Vologzhanina, N.A. Neklyudova, V.N. Serezhkin, 2009, published in Kristallografiya, 2009, Vol. 54, No. 3, pp. 483–487.     

Synthesis and X-ray structural investigation of K8[(UO2)2(C2O4)2(SeO4)4] · 2H2O

Single crystals of the compound K₈[(UO₂)₂(C₂O₄)₂(SeO₄)4] · 2H₂O (I) are synthesized, and their structure is investigated using X-ray diffraction. Compound I crystallizes in the monoclinic system with the unit cell parameters a = 14.9290(4) ?, b = 7.2800(2) ?, c = 15.3165(4) ?, β = 109.188(1)°, V = 1572.17(7) ?³, space group P2₁/n, Z = 2, and R = 0.0297. The uranium-containing structural units of crystals I are dimers of the composition [(UO ₂)₂(C₂O₄)₂(SeO₄)₄]⁸⁻, which belong to the crystal-chemical group AB ⁰¹ B ² M ¹ (A = UO₂²⁺, B ⁰¹ = C₂O₄²⁻, B ² = SeO₄²⁻, M ¹ = SeO₄²⁻) of the uranyl complexes. The [(UO₂)₂(C₂O₄)₂(SeO₄)₄]⁸⁻ dimers are joined into a three-dimensional framework through electrostatic interactions with the outer-sphere potassium cations. Original Russian Text ? L.B. Serezhkina, E.V. Peresypkina, A.V. Virovets, A.G. Verevkin, D.V. Pushkin, 2009, published in Kristallografiya, 2009, Vol. 54, No. 1, pp. 68–71.     

A Comparative Study of (tBu3Si)SiX2SiX2(SitBu3) (X?=?Cl, Br, I) Including the Result of the X-Ray Structure Analysis of (tBu3Si)SiI2SiI2(SitBu3)

Abstract  

The tetraiodotetrasilane (tBu₃Si)SiI₂SiI₂(SitBu₃) can be prepared from precursor (tBu₃Si)SiH₂SiH₂(SitBu₃). When (tBu₃Si)SiH₂SiH₂(SitBu₃) was treated with an excess of iodine at 120 °C, (tBu₃Si)SiI₂SiI₂(SitBu₃) was formed. X-ray quality crystals of (tBu₃Si)SiI₂SiI₂(SitBu₃) were grown from benzene at ambient temperature. The tetraiodotetrasilane (tBu₃Si)SiI₂SiI₂(SitBu₃) crystallizes in the monoclinic space group C2/c, a = 10.0110(10) ?, b = 13.9130(10) ?, c = 25.422(2) ?, β = 99.072(4)°, V = 3496.6(5) ?³, Z = 4, d _calcd = 1.829 g cm³; R ₁ = 0.0844, wR ₂ = 0.1854 for 3,017 reflections with I > 2σ(I). X-ray-crystallographic data show that the bromo and iodo derivatives (tBu₃Si)SiX₂SiX₂(SitBu₃) (X = Br, I) are isomorphous. The solid-state structure of (tBu₃Si)SiI₂SiI₂(SitBu₃) as well as those of (tBu₃Si)SiX₂SiX₂(SitBu₃) (X = Cl, Br) reveals a staggered conformation which adopts a trans-orientation of the supersilyl substituent. Unequal dihedral angles as found in (tBu₃Si)SiX₂SiX₂(SitBu₃) (X = Cl, Br, I) indicate that these compounds are sterically overcrowded.     

ac Conductivity of 4.5 TiO2−x · 2 P2O5

The ac conductivity of a member of the family of glasses 4.5 TiO_2?x · 2 P₂O₅ has been measured between 77 and 300 K, and up to 100 kHz. The dc conductivity was measured over only part of this temperature range. The measured ac conductivity can be represented by σ_ac = σ₀ + σ₁ω^s, with s < 1, and temperature dependent. A similar equation describes the ac dielectric constant, ?_ac = ?₀ + ?₁ω^s?1, where $\text{?}{}_1\text{= σ}{}_1\text{tan}\text{1}\text{2}\text{sπ}$. A simple proportionality of s to temperature holds at low temperature; at the higher temperatures, the T-dependence of s is no longer simple. The observed behaviour of the ac properties of this glass is in general accordance with a recently proposed model for systems where transport occurs by hopping. The over-all behaviour is comparable to other transition metal glasses.Using the model and treating the carriers as polarons yields an expression for s in terms of temperature. Values for the polaron radius and the effective dielectric constant are then extracted from the measurements. These values are in good agreement with values for similar systems obtained by other means.     

Synthesis and structure of {NH2(C2H5)2}2[(UO2)2(C2O4)(CH3COO)4] · 2H2O

Single crystals of the compound {NH₂(C₂H₅)₂}₂[(UO₂)₂C₂O₄(CH₃COO)₄] · 2H₂O (I) are synthesized, and their structure is investigated using X-ray diffraction. Compound I crystallizes in the monoclinic system with the unit cell parameters a = 9.210(2) ?, b = 14.321(3) ?, c = 12.659(3) ?, β = 105.465(13)°, V = 1609.2(6) ?³, space group P2₁/c, Z = 2, and R = 0.0198. The structural units of crystals I are binuclear groups of the composition [(UO₂)₂C₂O₄(CH₃COO)₄]²⁻ with an island structure, which belong to the crystal-chemical group A ₂ K ⁰² B ₄⁰¹ (A = UO₂²⁺, K ⁰² = C₂O₄²⁻, B ⁰¹ = CH₃COO⁻) of the uranyl complexes, diethylammonium cations, and water molecules. The uranium-containing groups are joined into a three-dimensional framework through electrostatic interactions with diethylammonium cations and a system of hydrogen bonds, which are formed with the participation of the atoms involved in the composition of the water molecules, oxalate ions, acetate ions, and diethylammonium cations. Original Russian Text ? L.B. Serezhkina, A.V. Vologzhanina, N.A. Neklyudova, V.N. Serezhkin, 2009, published in Kristallografiya, 2009, Vol. 54, No. 1, pp. 65–67.     

Crystal Structure and Magnetic Properties of the Dinuclear MnII Compound [Mn2(bpy)4(2-ClC6H4COO)2](ClO4)2·2EtOH

Abstract  

The synthesis and crystal structure of the dinuclear manganese (II) compound [Mn₂(bpy)₄(2-ClC₆H₄COO)₂](ClO₄)₂·2EtOH is described. The complex crystallizes in the monoclinic system, space group P2₁/n with a = 12.2067(18), b = 17.335(3), c = 13.706(3) ? and β = 92.606(8)°. In this structure, two manganese ions are bridged by two 2-chlorobenzoate ligands in a syn–anti mode. The hexa-coordination of each manganese is completed by two 2,2′-bipyridine ligands. Two perchlorate anions and two molecules of ethanol complete the packing. In order to check the magnetic properties previously reported from a powder sample, new magnetic studies have been carried out from a crystal sample, obtaining J = −1.79 cm⁻¹ and g = 2.00 (H = −JS ₁ ·S ₂ ).     

A study of the mechanisms of defect formation in K2Ni(SO4)2 · 6H2O/K2Co(SO4)2 · 6H2O bicrystals grown from aqueous solutions

The K₂Co(SO₄)₂ · 6H₂O-K₂Ni(SO₄)₂ · 6H₂O system has been studied, and a series of K₂Ni(SO₄)₂ · 6H₂O/K₂Co(SO₄)₂ · 6H₂O bicrystals have been grown. The processes of defect formation at the substrate/layer interface K₂Co(SO₄)₂ · 6H₂O/K₂Ni(SO₄)₂ · 6H₂O are studied by probe microanalysis, X-ray topography, and optical microscopy. It is found that inclusions and threading dislocations are formed at the interface, due to which elastic stresses relax in the crystal. Nickel is nonuniformly distributed in the layer; its concentration decreases with an increase in the layer thickness, which is indicative of substrate dissolution in the initial stage of interaction. A way for the elastic mismatch stresses to relax in heterostructures of brittle crystals obtained from solutions at low temperatures is proposed which implies the formation of inclusions at the substrate/layer interface. Original Russian Text ? M.S. Grigor’eva, A.é. Voloshin, E.B. Rudneva, V.L. Manomenova, S.N. Khakhanov, V.Ya. Shklover, 2009, published in Kristallografiya, 2009, Vol. 54, No. 4, pp. 679–687.     

Structure, thermal, and infrared analyses of [NH3(CH2)3NH3]2[Ni(HP2O7)2(H2O)2] ? 4H2O

[NH₃(CH₂)₃NH₃]₂[Ni(HP₂O₇)₂(H₂O)₂] 4H₂O (NiDAP) is a new diphosphate of transition metallic and organic cations obtained from a mixture of H₄P₂O₇, 2NiCO₃ Ni(OH)₂ 4H₂O and NH₂(CH₂)₃NH₂ in a 1:1/6:1 molar ratio. This mixed organo-mineral compound crystallizes in the triclinic system, P¯, with the unit cell dimensions: a = 7.3678(3)~Å, b = 7.8018(5)Å, c = 11.1958(7)Å, = 76.914(4), = 81.052(4), = 85.46(1), V = 618.57(6)ų and Z = 1. The crystal structure of NiDAP consists of a complex anion, [Ni(HP₂O₇)₂(H₂O)₂]^4– and a diammoniumpropane cation. The complex anion is built up from two neutral water molecules (OW1) and two diphosphosphoric anions coordinated to Ni(II) in a bidentate chelating manner. (OW1) molecules link anionic complexes, [Ni(HP₂O₇)₂(H₂O)₂]^4– to create a thick bidimensional layers parallel to the (a, b) plane. These layers are interconnected in three dimensions through hydrogen bonds established between organic cations, the remaining water molecules OW2, OW3, and some external oxygen atoms of the anionic complex arrays. NiDAP was also characterized by IR spectroscopy, TG-DTA, and DSC analyses.     

Synthesis and X-ray structural investigation of (C3N6H7)4(CN3H6)2[UO2(CrO4)4] · 4H2O and (H3O)6[UO2(CrO4)4]

Single crystals of the compounds (C₃N₆ H₇)₄(CN₃H₆)₂[UO₂(CrO₄)₄] · 4H₂O (I) and (H₃O)₆[UO₂(CrO₄)₄] (II) are synthesized, and their structures are investigated using X-ray diffraction. Compound I crystallizes in the triclinic system with the unit cell parameters a = 6.3951(8) ?, b = 10.8187(16) ?, c = 16.9709(18) ?, α = 93.674(4)°, β = 97.127(4)°, γ = 92.020(4)°, space group, P Z = 1, V = 1161.6(3) ?³, and R = 0.0470. Crystals of compound II belong to the monoclinic system with the unit cell parameters a = 14.3158(4) ?, b = 11.7477(3) ?, c = 13.1351(4) ?, β= 105.836(1)°, space group C2/c, Z = 4, V = 2125.2(1) ?³, and R = 0.0213. The uranium-containing structural units of crystals I and II are mononuclear anionic complexes of the composition [UO₂(CrO₄)₄]⁶⁻ with an island structure, which belong to the crystal-chemical group Am ₁⁴ (A = UO₂₊², M ¹ = CrO₂₋⁴) of the uranyl complexes. The [UO₂(CrO₄)₄]⁶⁻ anionic complexes are joined into a three-dimensional framework through the electrostatic interactions with outer-sphere cations and a system of hydrogen bonds. Original Russian Text ? L.B. Serezhkina, E.V. Peresypkina, A.V. Virovets, A.G. Verevkin, D.V. Pushkin, 2009, published in Kristallografiya, 2009, Vol. 54, No. 2, pp. 284–290.     

Reactivity of [Re2(CO)8(MeCN)2] With 1-vinylimidazole: X-ray Structures of [Re2(CO)8{η1-NC3H3N(CH=CH2)}2] and [ReCl2(CO)2{η1-NC3H3N(CH=CH2)}2]

Abstract  Treatment of [Re₂(CO)₈(MeCN)₂] with excess 1-vinylimidazole in refluxing benzene gives three new compounds [Re₂(CO)₉{η ¹-NC₃H₃N(CH=CH₂)}] (1), [Re₂(CO)₈{η ¹-NC₃H₃N(CH=CH₂)}₂] (2) and [ReCl₂(CO)₂{η ¹-NC₃H₃N(CH=CH₂)}₂] (3) in 11, 32 and 2% yields, respectively. The solid-state structures of complexes 2 and 3 have been determined by single crystal X-ray diffraction studies. Compound 2 crystallizes in the monoclinic space group C2/c, with lattice parameters a = 13.8378(5) ?, b = 11.8909(5) ?, c = 14.4591(6) ?, β = 116.6470(10)°, Z = 4 and V = 2131.99(15) ?³. Compound 3 crystallizes in the monoclinic space group C2/c, with lattice parameters a = 10.1028(3) ?, b = 13.5640(5) ?, c = 12.5398(4) ?, β = 109.637(2)°, Z = 4 and V = 1618.4(9) ?³. The disubstituted dinuclear compound 2 contains two 1-vinylimidazole ligands coordinated through the imino nitrogen atoms at the equatorial sites, whereas the mononuclear compound 3 contains two carbonyl ligands, two N coordinated η ¹-1-vinylimidazole ligands and two terminal Cl ligands. Graphical Abstract  Two dinuclear complesxes [Re₂(CO)₉{η ¹-NC₃H₃N(CH=CH₂)}] (1) and [Re₂(CO)₈{η ¹-NC₃H₃N(CH=CH₂)}₂] (2) and the mononuclear [ReCl₂(CO)₂{η ¹-NC₃H₃N(CH=CH₂)}₂] (3) were obtained from the reaction of [Re₂(CO)₈(MeCN)₂] with excess 1-vinylimidazole at 80 °C. The X-ray structrures of 2 and 3 are described.      

On the structure of amorphous GexTe1−x systems

Calculations have been made for the quadrupole splitting of a $\text{3}\text{2}$ spin state of Te¹²⁵ in an amorphous Ge_xTe_1?x system. The results favour the existence of a threefold coordinated black phosphorus structure with an excess of TeTe chains for x-values between o and 0.5; beyond 0.5, threefold coordinated GeTe and an excess of amorphous Ge coexist.     

Crystal and molecular structure of Sr2( Edta ) · 5H2O, Sr2(H2 Edta )(HCO3)2 · 4H2O, and Sr2(H2 Edta )Cl2 · 5H2O strontium ethylenediaminetetraacetates

Three Sr²⁺ compounds with the Edta ⁴⁻ and H₂ Edta ²⁻ ligands—Sr₂(Edta) · 5H₂O (I), Sr₂(H₂ Edta)(HCO₃)₂ · 4H₂O (II), and Sr₂(H₂ Edta)Cl₂ · 5H₂O (III)—are synthesized, and their crystal structures are studied. In I, the Sr(1) atom is coordinated by the hexadentate Edta ⁴⁻ ligand following the 2N + 4O pattern and by two O atoms of the neighboring ligands, which affords the formation of zigzag chains. The Sr(2) atom forms bonds with O atoms of five water molecules and attaches itself to a chain via bonds with three O atoms of the Edta ⁴⁻ ligands. The Sr(1)-O and Sr(2)-O bond lengths fall in the ranges 2.520(2)–2.656(3) and 2.527(3)–2.683(2) ?, respectively. The Sr(1)-N bonds are 2.702(3) and 2.743(3) ? long. In II and III, the H₂ Edta ²⁻ anions have a centrosymmetric structure with the trans configuration of the planar ethylenediamine fragment. The N atoms are blocked by acid protons. In II, the environment of the Sr atom is formed by six O atoms of three H₂ Edta ligands, two O atoms of water molecules, and an O atom of the bicarbonate ion, which is disordered over two positions. In III, the environment of the Sr atom includes six O atoms of four H₂ Edta ²⁻ ligands and three O atoms of water molecules. The coordination number of the Sr atoms is equal to 8 + 1. In II and III, the main bonds fall in the ranges 2.534(3)–2.732(2) and 2.482(2)–2.746(3) ?, whereas the ninth bond is elongated to 2.937(3) and 3.055(3) ?, respectively. In II, all the structural elements are linked into wavy layers. The O-H…O interactions contribute to the stabilization of the layer and link neighboring layers. In III, hydrated Sr²⁺ cations and H₂ Edta ^– anions form a three-dimensional [Sr₂(H₂ Edta)(H₂O)₃] _n ²ⁿ⁺ framework. The Cl⁻ anions are fixed in channels of the framework by hydrogen bonds with four water molecules. In II and III, the N-H groups form four-center N-H…O₃ hydrogen bonds, which include one intermolecular and two intramolecular components. PACS numbers: 61.66.Hq Original Russian Text ? I.N. Polyakova, A.L. Poznyak, V.S. Sergienko, 2009, published in Kristallografiya, 2009, Vol. 54, No. 2, pp. 262–267.     

Investigations of 2-Thiazoline-2-thiol as a Ligand: Synthesis and X-ray Structures of [Mn2(CO)7(μ-NS2C3H4)2] and [Mn(CO)3(PPh3)(κ2-NS2C3H4)]

Abstract  Treatment of Mn₂(CO)₁₀ with 2-thiazoline-2-thiol in the presence of Me₃NO at room temperature afforded the dimanganese complexes [Mn₂(CO)₇(μ-NS₂C₃H₄)₂] (1) and [Mn₂(CO)₆(μ-NS₂C₃H₄)₂] (2) in 51 and 34% yields, respectively. Compound 1 was quantitatively converted into 2 when reacted with one equiv of Me₃NO. Reaction of 1 with triphenylphosphine at room temperature furnished the mononuclear complex [Mn(CO)₃(PPh₃)(κ ²-NS₂C₃H₄)] (3) in 66% yield. All three new complexes have been characterized by elemental analyzes and spectroscopic data together with single crystal X-ray diffraction studies for 1 and 3. Compound 1 crystallizes in the orthorhombic space group Pbca with a = 12.4147(2), b = 16.2416(3), c = 19.0841(4) ?, β = 90°, Z = 8 and V = 3848.01(12) ?³ and 3 crystallizes in the monoclinic space group P 2₁/n with a = 10.41730(10), b = 14.7710(2), c = 14.9209(2) ?, β = 91.1760(10)°, Z = 4 and V = 2295.45(5) ?³. Graphical Abstract  Two new dimanganese complexes [Mn₂(CO)₇(μ-NS₂C₃H₄)₂] (1) and [Mn₂(CO)₆(μ-NS₂C₃H₄)₂] (2) were formed when [Mn₂(CO)₁₀] was treated with 2-thiazoline-2-thiol in the presence of Me₃NO. Compound 2 reacts with PPh₃ to give the monomeric complex [Mn(CO)₃(PPh₃ )(κ ²-NS₂C₃H₄)]. The structures of 1 and 3 were established by crystallography. Shishir Ghosh, Faruque Ahmed, Rafique Al-Mamun, Daniel T. Haworth, Sergey V. Lindeman, Tasneem A. Siddiquee, Dennis W. Bennett, Shariff E. Kabir Investigations of 2-thiazoline-2-thiol as a ligand: Synthesis and X-ray structures of [Mn₂(CO)₇(μ-NS₂C₃H₄)₂] and [Mn(CO)₃ (PPh3)(κ ²-NS₂C₃H₄)].      

Crystal Structures of Two Aromatic Zinc(II) Carboxylates: [Zn(4-Chlorosalicylato)2(H2O)4]·2theophylline·(H2O)2 and Unique [Zn(5-Chlorosalicylato)2(isonicotinamide)2(H2O)]

Abstract  

The crystal structures of two zinc(II) 4-chloro- and 5-chlorosalicylate complexes, [Zn(4-ClC₆H₃-2-(OH)COO)₂(H₂O)₄]·2tph·(H₂O)₂ (I) and [Zn(5-ClC₆H₃-2-(OH)COO)₂(ina)₂(H₂O)] (II), where tph is theophylline and ina is isonicotinamide, have been determined using X-ray diffraction methods. Crystals of both (I) and (II) are triclinic, space group P-1, with Z = 1 in a cell with a = 7.2220(3), b = 8.59700(10), c = 16.0210(5) ?, α = 75.990(2), β = 83.959(2), γ = 68.455(2)°, V = 897.54(5) ?³ (I) and with Z = 2 in a cell with a = 11.4148(11), b = 11.5327(10), c = 12.0685(13) ?, α = 63.458(6), β = 87.547(8), γ = 89.387(7)°, V = 1419.9(2) ?³ (II). The coordination environment of the zinc(II) atom of compound (I) consists of two unidentate carboxylate oxygen atoms and four oxygen atoms of aqua ligands, forming a distorted octahedral configuration. Two theophylline molecules and the remaining water molecules are bound only by hydrogen bonds. The Zn atom of compound (II) is pentacoordinated with two unidentate carboxylate oxygen atoms, two pyridine nitrogen atoms of isonicotinamide ligands, and the oxygen atom of the aqua ligand, forming a distorted configuration between square pyramid and trigonal bipyramid. In both complexes intramolecular O–H···O hydrogen-bonding interactions are present. In the crystal structures, molecules are linked by intermolecular O–H···O and N–H···O hydrogen bonds. The structures are analyzed and compared to the similar Zn(II) complexes, with the chromophores ZnO₆ and ZnO₃N₂.     

Crystal Structures and Thermal Properties of Two Transition-Metal Compounds {[Ni(DNI)2(H2O)3][Ni(DNI)2 (H2O)4]}·6H2O and Pb(DNI)2(H2O)4 (DNI?=?2,4-Dinitroimidazolate)

Abstract  

Two transition-metal compounds derived from 2,4-dinitroimidazole, {[Ni(DNI)₂(H₂O)₃][Ni(DNI)₂(H₂O)₄]}·6H₂O, 1, and Pb(DNI)₂(H₂O)₄, 2, were characterized by elemental analysis, FT-IR, TG-DSC and X-ray single-crystal diffraction analysis. Crystal data for 1: monoclinic, space group C2/c, a = 26.826(3), b = 7.7199(10), c = 18.579(2) ?, β = 111.241(2)° and Z = 4; 2: monoclinic, space group C2/c, a = 6.5347(6), b = 17.1727(17), c = 14.1011(14) ?, β = 97.7248(10) and Z = 4. Compound 1 contains two isolated nickel centers in its structure, one being six-coordinate and another five-coordinate. The structure of 2 contains a lead (II) center surrounded by two chelating DNI ligands and four water molecules in distorted square-antiprism geometry. The abundant hydrogen bonds in two compounds link the molecules into three-dimensional network and stabilize the molecules. The TG-DSC analysis reveals that the first step is the loss of water molecules and the final residue is the corresponding metal oxides and carbon.     

Crystal Structure of a Trinuclear Mercury(II) Cyanide Complex of Tetramethylthiourea, [{(Tetramethylthiourea)2Hg(CN)2}2·Hg(CN)2]

Abstract  

The title compound was prepared by reacting mercury(II) cyanide and tetramethylthiourea (Tmtu) in the molar ratio of 1:1.75. It was characterized by IR and NMR (¹H and ¹³C) spectroscopy, and X-ray crystallography. The appearance of a band around 2,200 cm⁻¹ in IR and a resonance around 145 ppm in ¹³C NMR indicated the binding of cyanide to mercury(II). The crystal structure of the title complex, [{(tetramethylthiourea)₂Hg(CN)₂}₂·Hg(CN)₂] (1) consists of two independent [(Tmtu)₂Hg(CN)₂] moieties bridged by a Hg(CN)₂ unit. The mercury atom in [(Tmtu)₂Hg(CN)₂] unit is coordinated to two thione sulfur atoms of Tmtu and to two cyanide carbon atoms in a distorted tetrahedral mode.     

Infrared transmission of (R2O OR R’O)–(TiO2, Nb2O5 OR Ta2O5)-Al2O3 glasses

The new families of aluminate glasses obtained by the present authors from their melts in the systems K₂O–Ta₂O₅–Al₂O₃, Na₂O–K₂O–Ta₂O₅–Al₂O₃, K₂O –Cs₂O– Ta₂O₅–Al₂O₃, K₂O–Nb₂O₅–Al₂O₃, Na₂Oz.sbnd;K₂O–TiO₂–Al₂O₃, BaO–TiO₂–Al₂O₃, BaO–ZrO₂–TiO₂–Al₂O₃ and Na₂O–K₂O–BaO–ZrO₂–Ta₂O₅–TiO₂ –Al₂O₃ showed high transmissions of visible and infrared (IR) radiation ranging from 0.4 to about 6 μm, as well as high refractive indices up to 2.0. Their physical and chemical properties such as glass-forming ability, softening temperature, hardness and hygroscopicity were comparable to conventional silicate glasses. These properties are useful for IR applications. The cause of the high IR transmission of the aluminate glasses was interpreted in terms of the masses of the constituent cations and the single bond strengths of the cations with oxygen ions.     

Synthesis and Structure of a Silver(I) Complex {[Ag5(L)2(NO3)4](NO3)(CHCl3)2}n [L?=?2,3-bis(pyrimidine-2-thiomethyl)quinoxaline]

Abstract  The reaction of the dithioether ligand, 2,3-bis(pyrimidine-2-thiomethyl)quinoxaline (L) with AgNO₃, leads to the formation of a novel complex {[Ag₅(L)₂(NO₃)₄](NO₃)(CHCl₃)₂}n 1, which has been characterized by single-crystal X-ray diffraction analysis: monoclinic, space group C2/c, with a = 34.741(7), b = 9.930(2), c = 17.004(4) ?, β = 106.497(6)° and V = 5625(2) ?³.Complex 1 consists of 2D {[Ag₅(L)₂(NO₃)₄]⁺}n cations, uncoordinated anions and CHCl₃ solvent molecules. In 1, there exist three crystallographic independent Ag^I centers, which adopt different coordination geometries. There exist π–π stacking interactions in the complex and these weak interactions further stabilize the crystal structure in the solid state. The coordination feature of the ligand has been investigated by DFT calculations. Index Abstract  Synthesis and Structure of a Silver(I) Complex {[Ag₅(L)₂(NO₃)₄](NO₃)(CHCl₃)₂}_n [L = 2,3-bis(pyrimidine-2-thiomethyl)quinoxaline] Chao-Yan Zhang, Qian Gao, Ya-Bo Xie*, and Jian-Bo Feng The crystal structure of complex {[Ag₅(L)₂(NO₃)₄](NO₃)(CHCl₃)₂}n (L = 2,3-bis(pyrimidine-2-thiomethyl)quinoxaline) consists of 2D {[Ag₅(L)₂(NO₃)₄]⁺}n cations, uncoordinated anions and CHCl₃ solvent molecules. There exist three crystallographic independent Ag^I centers, which adopt different coordination geometries. The coordination feature of the ligand has been investigated by DFT calculations.      

X-ray diffraction study of R2[UO2(C3H2O4)2] ·H2O (R = K or Rb)

Compounds K₂[UO₂(C₃H₂O₄)₂] · H₂O (I) and Rb₂[UO₂(C₃H₂O₄)₂] · H₂O (II) are synthesized and their crystal structures are determined by X-ray diffraction. The compounds crystallize in the monoclinic crystal system; for I, a = 7.1700(2) ?, b =12.3061(3) ?, c = 14.3080(4) ?, β = 95.831(2)°, space group P2₁/n, Z = 4, and R = 0.0275; for II, a = 7.1197(2) ?, b = 12.6433(4) ?, c = 14.6729(6) ?, β = 96.353(2)°, space group P2₁/n, Z = 4, and R = 0.0328. It is found that I and II are isostructural. The main structural units of the crystals are the [UO₂(C₃H₂O₄)₂]²⁻ chains, which belong to the AT ¹¹ B ⁰¹ (A = UO₂²⁺, T ¹¹, and B ⁰¹ = C₃H₂O₄²⁻) crystal chemical group of uranyl complexes. The chains and alkali metal ions R (R = K or Rb) are connected by electrostatic interactions and hydrogen bonds. Some specific structural features of [UO₂(C₃H₂O4)₂]²⁻ complex groups are discussed.     

Synthesis, Crystal Structure and Fluorescence Property of a Binuclear Zn(II) Complex: [Zn2(μ-N3)2(N3)2(L)2] [L?=?1-(1,10-phenanthrolin-2-yl)-2-pyridone]

Abstract  Hydrated zinc perchlorate reacted with sodium azide and 1-(1,10-phenanthrolin-2-yl)-2-pyridone (L) in methanol solution and resulted in the formation of a new binuclear complex: [Zn₂(μ-N₃)₂(N₃)₂(L)₂]. The complex has been characterized by elemental analysis and IR spectrum, and its crystal structure determined by X-ray crystallography and the complex crystallizes in the monoclinic system with space group P2₁/c and a = 11.409(2), b = 8.0733(15), c = 18.163(3) Ǻ, β = 99.095(3)°. In the complex two azide anions act as bridge ligand and another two azide anion and two 1-(1,10-phenanthrolin-2-yl)-2-pyridone function as terminal ligands, and Zn(II) ion lies in a distorted triangle bipyramid geometry. Index Abstract  The title binuclear Zn(II) complex was synthesized by zinc perchlorate, sodium azide and 1-(1,10-phenanthrolin-2-yl)-2-pyridone and its crystal structure determined. Single crystal X-ray diffraction analysis reveals that azide anion function as both bridge ligand and terminal ligand, and 1-(1,10-phenanthrolin-2-yl)-2-pyridone only acts as a terminal ligand.