Synthesis and crystal structures of two new complexes [M(OH2)(HDPA)2]·3H2O (M = Mn, Co)

Two new transition metal complexes of [M(OH₂)(HDPA)₂]·3H₂O (M=Mn(1); M=Co(2)) (H₂DPA, 2,6-pyridine-dicarboxylic acid) have been prepared at room temperature from the reaction of MCl₂·6H₂O (M=Mn or Co) and H₂DPA in the mixed solvent of H₂O and EtOH in the presence of piperazine, and were characterized by X-ray analysis, elemental analysis. X-ray analysis reveals that the coordination geometries of Mn²⁺ and Co²⁺ are of octahedron and severely distorted square-based pyramid, respectively. Crystal data: [Mn(OH₂)(HDPA)₂]·3H₂O (1), Mr=459.23, monoclinic, P2(1)/n, a=7.0056(3), b=(23.8125(12), c=10.7444(3) ?, β=99.834(2)°, Z=4, V=1766.28(13) ?³, R ₁=0.0586, wR ₂=0.1448 [I>2σ(I)]; Co(OH₂)(HDPA)₂]·3H₂O (2), Mr=463.22, monoclinic, P2(1)/n, a=7.0014(2), b=23.8346(7), c=10.7212(4) ?, β=99.8540(10)°, Z=4, V=1762.71(10) ?³, R ₁=0.0474, wR ₂=0.1366 [I>2σ(I)].     

Direct and outer-sphere coordination of the magnesium ions in the crystal structures of complexes with 2-furancarboxylic acid (I) and 3-furancarboxylic acid (II)

(I) Mg₂C₂₀H₂₄O₁₈ monoclinic,PT,a=10.760(2) Å,b=11.052(2) Å,c=12.822(3) Å, α=105.31(3)^o, β=98.18(3)^o, γ=91.59(3)^o,Z=2. (II) MgC₁₀H₁₄O₁₀, monoclinic,C2/c,a=30.817(6)Å,b=10.499(2)Å,c=9.000(2)Å, β=91.31(3)^o,Z=8. Magnesium in complexes with furoic acids reveals two ways of coordination: direct, when furoic anions are bonded to Mg²⁺ in an ionic fashion and outer-sphere, when cations bind water in the first coordination sphere and furancarboxylic ligands are hydrogen bonded to the water molecules. This results in the formation of three bridging systems: ?Mg?O_carboxyl?C?O_carboxyl?Mg?, ?Mg?O_water ?O_carboxyl?C?O_carboxyl?C?O_carboxyl?Mg?, and ?Mg?O_water?O_carboxyl?C?O_carboxyl?O_water?Mg?. Magnesium 2-furancarboxylate (I) is dimeric, while magnesium 3-furancarboxylate (II) exhibits a polymeric structure.     

Biscyclopentadienides with transition metal-mercury bonds. II: Dithiocarbamato derivatives of molybdenum and tungsten,and X-ray structure of (η5-C5H5)2Mo[HgS2CN(C2H5)2]2

The reactions in THF or benzene between Cp₂ M (HgX)₂ ·x HgX ₂ (M = Mo or W; O ?x ? 1;X ^? = Cl^?, Br^?, I^?, SCN^?, OAc^?) and sodium diethyl-dithiocarbamate $$\begin{gathered} Cp_2 M\left( {HgX} \right)_2 .xHgX_2 + \left( {2 + x} \right)Nadtc \rightleftharpoons Cp_2 M\left( {Hgdtc} \right)_2 \hfill \\ + xHg\left( {dtc} \right)_2 + \left( {2 + x} \right)NaX \hfill \\ \end{gathered} $$ as well as between Cp₂ MH₂ and mercury diethyldithiocarbamate $$x2Cp_2 MH_2 + 2Hg\left( {dtc} \right)_{2 - } Cp_2 M\left( {Hgdtc} \right)_2 + \left\{ {Cp_2 Mdtc} \right\}dtc + 2H_2 $$ give the compound Cp₂ M(Hgdtc)₂ (dtc is diethyldithiocarbamate anion). The structure of the molybdenum complex determined by the X-ray method (a = 12.776(4),b = 7.835(4),c = 27.397(7) Å β = 111.18(2) °; space groupC2/c (No. 15);Z = 4) consists of discrete molecules occupying special positions on two-fold axes. A short Mo-Hg distance of 2.643(8) Å and a rather long Hg-S one of 2.50(2) Å were found. The diethyldithiocarbamate anion behaves like a monodentate ligand. IR and¹H,¹³C NMR results agree with the molecular structure determination and confirm a weak bond between mercury and dithiocarbamate and strong molybdenum-mercury bond. A considerable solvent effect (C₆D₆ vs. CDCl₃ solutions) has been observed on the¹H chemical shifts of both dtc and Cp ligands. The {Cp₂Modtc}⁺ X ^? (X = dtc and PF₆) complexes, although not obtained in a pure form, were included in the discussion of the spectroscopic features of those with theM-Hg bonds.     

Morphotropy, isomorphism, and polymorphism of Ln 2 M 2O7-based (Ln = La-Lu, Y, Sc; M = Ti, Zr, Hf, Sn) oxides

Structural studies of compounds of variable composition and measurements of their conductivity have made it possible to identify new oxygen-ion-conducting rare-earth pyrochlores, Ln ₂Ti₂O₇ (Ln = Dy-Lu) and Ln ₂Hf₂O₇ (Ln = Eu, Gd), with intrinsic high-temperature oxygen ion conductivity (up to 1.4 × 10^?2 S/cm at 800°C). Twenty six systems have been studied, and more than 50 phases based on the Ln ₂ M ₂O₇ (Ln= La-Lu; M = Ti, Zr, Hf) oxides have been synthesized and shown to be potential oxygen ion conductors. The morphotropy and polymorphism of the Ln ₂ M ₂O₇ (Ln = La-Lu; M = Ti, Zr, Hf) rare-earth pyrochlores have been analyzed in detail for the first time. Thermodynamic and kinetic (growth-related) phase transitions have been classified with application to the pyrochlore family.     

Gaseous complexes — Their role in chemical transport

The literature about gaseous complexes consisting of two different metals and one halide is reviewed. With respect to chemical transport the most important properties of gaseous complexes are their appreciable thermodynamic stability and their volatility. This is clearly illustrated in the case of RbSnCl₃, whose vapour in equilibrium with the melt at 980 °K contains around 25 mole% of RbSnCl₃ (g) and whose vapour pressure is around 20 times higher than that of RbCl. Gaseous complexes of the type Mⁿ⁺L₂Cl_n+6 (M = Mg²⁺, Ca²⁺, Mn²⁺, Co²⁺, Ni²⁺, Nd³⁺, Cr³⁺; L = Fe³⁺, Al³⁺) can, in an atmosphere of L₂Cl₆(g), have vapour pressures up to 10⁷ times higher than the vapour pressure of MCl_n. The importance of such gaseous complexes for the chemical transport of MCl_n and of compounds containing Mⁿ⁺ will be discussed.     

Fluorite M1 − x R xF2 + x phases (M = Ca, Sr, Ba; R = rare earth elements) as nanostructured materials

The structural defects (M ²⁺ and R ³⁺ in the noncubic environment of F^?, interstitial F^?, and anion vacancies) in nonstoichiometric M _{1 ? x} R_xF_{2 + x} crystals with the CaF₂ structure form {M ₈[R ₆F_68-69]} superclusters of nanometer linear dimensions. This fact allows one to classify the M _{1 ? x} R _xF_{2 + x} phases as nanostructured materials (NSM). The superclusters concentrate rare-earth ions (R ³⁺ = RE). In a M _{1 ? x} R _xF_{2 + x} crystal with the fluorite cation motif, two chemically different parts can be separated: the R ³⁺-depleted matrix and the R ³⁺-enriched clusters. The M _{1 ? x} R _xF_{2 + x} phases are the first NSM among fluorides; they constitute a new type of these materials in which different chemical compositions of the matrix and nanoinclusions are combined with their isostructurality and coherent conjugation of the crystal lattices. Superclusters can also form associates with linear dimensions of tens or hundreds of angstroms. A model is suggested which describes the main characteristic of such NSMs. These materials behave as single crystals in X-ray, neutron, and electron diffraction experiments. The influence of microheterogeneity on some physical properties of the M _{1 ? x} R _xF_{2 + x} phases is also considered.     

Ionic conductivity of cold-pressed ceramics from grinding of R0.95M0.05F2.95 solid electrolytes (R = La,Nd; M = Ca,Sr, Ba) synthesized by reaction in melt

Cold-pressed ceramics of fluorine-conducting solid electrolytes La_{1 ? y} M _y F_{3 ? y} (M = Ca, Sr, Ba) and Nd_{1 ? y} Ca _y F_{3 ? y} with y = 0.95 have been synthesized in a melt of RF₃ (R = La, Nd) and MF₂ components in a fluorinating atmosphere and ground in a ball mill. The as-prepared ceramics require annealing, during which their porosity decreases and the conductivity is stably increased (by a factor of 250 for the R _{1 ? y} M _y F_{3 ? y} composition at 293 K). The Nd_0.95Ca_0.05F_2.95 and Nd_0.95Ca_0.05F_2.95 compositions have a maximum ionic conductivity σ(293 K) ～ 5 × 10^?6 Sm/cm. This value is larger (by a factor of about 10) than σ (293 K) for the R _{1 ? y} M _y F_{3 ? y} ceramics of tysonite phases prepared by mechanochemical synthesis with the cold pressing of reaction products.     

Crystal structure of [Pb(cis-anti-cis-dicyclohexyl-18-crown-6)(OH2)2][ClO4]2

[Pb(cis-anti-cis-dicyclohexyl-18-crown-6)(OH₂)₂][ClO₄]₂ was crystallized using a slightly modified literature method for the separation of dicyclohexyl-18-crown-6 isomers. It crystallizes in the monoclinic space groupP2₁/n witha=8.415(5),b=20.993(9),c=8.973(5) Å, β=111.56(6)^o, andD _calc=1.84 g/cm³ for Z=2. The Pb²⁺ ion resides on a crystallographic center of inversion and is coordinated to the six crown ether donors and two axial water molecules in a hexagonal bipyramidal geometry. The Pb-O(etheric) distances range from 2.694(4) to 2.743(4) Å while the Pb?OH₂ distance is 2.522(6) Å.     

Crystal structures of thecis andtrans isomers of dithiahexahydro[3.3]metacyclophane

Structures of both thecis andtrans isomers of dithiahexahydro[3.3]metacyclophane, ?C₆H₄?CH₂SCH₂?C₆H₁₀?CH₂SCH₂?, have been determined, wherecis andtrans refer to the attachments to the cyclohexane ring. Thecis form crystallizes in the monoclinic space groupP2₁/c witha=8.4299(11)Å,b=21.772(2)Å,c=8.9724(13)Å, β=116.574(11)^o, andZ=4. Thetrans isomer packs into the monoclinic space groupP2₁ witha=8.159(16)Å,b=10.185(5)Å,c=9.558(2)Å, β=112.435(18)^o, andZ=2. The cyclohexane ring of thecis isomer is in the chair conformation, while the cyclohexane of thetrans isomer is found in a twisted boat conformation.     

The structure of the π-molecular complex between 1,4-dihydro-9,10-anthrahydroquinone and 1,4-dihydro-9,10-anthraquinone

The structure of the π-molecular complex (10) was assigned on the basis of the solid state¹³C-nmr spectrum. The solid state¹³C-nmr spectrum of quinhydrone (12) has also been determined. Accurate¹H and¹³C chemical shift assignments have been made for the compounds3,5,6,7,8, and10 on the basis of HMQC and HMBC spectral data. The π-molecular complex10 crystallizes in the space groupP2₁ In with cell parameters:a=4.052 (1) Å,b=6.477 (1) Å,c=19.093 (2) Å, β=90.17 (1)^o,z=1,D _c =1.400 g mc^?32. Crystal and molecular structure of the title compound, C₂₈H₂₂O₄, has been determined by an X-ray analysis of10 by direct methods from diffractometer data and refined by full-matrix least-squares     

Structure of 1,4-bis(diiodophenylstannyl)butane

The molecule of I₂PhSnCH₂CH₂CH₂CH₂SnPhI₂ (1) in the solid state, is centrosymmetric with the molecular center-of-symmetry coincident with a crystallographic center-of-symmetry. It crystallizes in the monoclinic space group,P2₁/c (Z=2), witha=13.495(1) Å,b=6.844(1) Å,c=14.732(1) Å, and β=116.12(2)^o. The compounds consist of essentially individual molecules, separated by I(2)---I(2ⁱ) and I(2)---I(2ⁱⁱ) distances [4.258(12) Å], close to the sum of the van der Waals radii. There are no interactions between the two diiodophenylstannyl moieties. The tin atoms have slightly distorted tetrahedral geometries, with the bond angles at tin varying from 103.40(3) [I(1)?Sn?I(2)] to 117.0(3)⁰ [C(1)?Sn?C(7)] and with Sn?I(1) and Sn?I(2) bond lengths of 2.6980(9) and 2.7106(10) Å, respectively.¹H-,¹³C- and¹¹⁹Sn-NMR spectra in CDCl₃ solution have also been obtained.     

Nonstoichiometry in inorganic fluorides: I. Nonstoichiometry in MF m -RF n (m < n ≤ 4) systems

The manifestation of gross nonstoichiometry in MF _m -RF _n systems (m < n ?? 4) has been studied. Fluorides of 34 elements, in the systems of which phases of practical interest are formed, are chosen. To search for new phases of complex composition, a program for studying the phase diagrams of the condensed state (??200 systems) has been carried out at the Institute of Crystallography, Russian Academy of Sciences. The main products of high-temperature interactions of the fluorides of elements with different valences (m ?? n) are grossly nonstoichiometric phases of two structural types: fluorite (CaF₂) and tysonite (LaF₃). Systems of fluorides of 27 elements (M ¹⁺ = Na, K; M ²⁺ = Ca, Sr, Ba, Cd, Pb; R ³⁺ = Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu; R ⁴⁺ = Zr, Hf, Th, U) are selected; nonstoichiometric M _{1 ? x} R _x F _{m(1 ? x) + nx} phases, which are of greatest practical interest, are formed in these systems. The gross nonstoichiometry in inorganic fluorides is most pronounced in 80 MF₂ ? RF₃ systems (M = Ca, Sr, Ba, Cd, Pb; R are rare earth elements). The problems related to the growth of single crystals of nonstoichiometric phases and basic fields of their application as new fluoride multicomponent materials, the properties of which are controlled by the defect structure, are considered.     

Bimetallic hydrogen sulfates K4 M II[H(SO4)2]2(H2O)2 (M II = Mn or Zn)

Hydrogen sulfate hydrates K₄{M ^II[H(SO₄)₂]₂(H₂O)₂}, where M ^II = Mn or Zn, are synthesized, and their single-crystal structures are determined by X-ray diffraction. The structural units of the orthorhombic crystals (space group Pccn) are potassium and M ^II cations, SO ₄ ^2? and HSO ₄ ^? anions, and water molecules. Strong (2.52 Å) and moderate-in-strength (2.71–2.75 Å) hydrogen bonds link the anions and water molecules into hexamers. The M ^II cations, which have the octahedral environment (Mn-O, 2.14–2.19 Å and Zn-O, 2.07–2.11 Å), link the hexamers into flat layers. The structures of bimetallic hydrogen chalcogenate hydrates with different compositions are compared.     

Synthesis and crystal structures of bimetallic hydrogen sulfates M I M II [H(SO4)2](H2O)2 (M I = K, Cs; M II = Zn, Mn) and selenate KMg[H(SeO4)2](H2O)2

Single crystals of acid salt hydrates M ^I{M ^II[H(XO₄)₂](H₂O)₂}, where M ^I, M ^II, and X are K, Zn, and S (I); K, Mn, and S (II); Cs, Mn, and S (III); or K, Mn, and Se (IV), respectively, were synthesized and studied by X-ray diffraction analysis. Compounds I–IV (space group $P\bar 1$ ) are isostructural to each other and to hydrate KMg[H(SO₄)₂](H₂O)₂ (V) studied earlier. Structures I–V, especially, the M ^I-O, M ^II-O, and X-O distances and the O?H?O (2.44–2.48 Å) and O_w-H?O (2.70–2.81 Å) hydrogen bonds, are discussed.     

The molecular structures of two furanoheliangolides

The heliangolide-class sesquiterpene lactone 8β-angeloyloxy-9α-acetoxycalyculatolide, C₂₂H₂₆O₈,1, crystallizes in orthorhombic space groupP2₁2₁2₁ witha=12.455(3),b=12.601(3),c=14.023(5) Å,V=2200(1)Å,³ Z=4.R=0.059 for 1735 observed data. The 11,13-dihydro-11α, 13-epoxyatripliciolide-8β-angelate, C₂₀H₂₂O₇. 1/2 H₂O,2, crystallizes as the hemihydrate with two molecules in the asymmetric unit in triclinic space groupP1 witha=9.422(1),b=9.559(1),c=12.358(3) Å, α=101.62(2)°, β=91.30(2)°, γ=117.80(1)°,V=955.6(7)ų,Z=2.R=0.046 for 3607 observed data. In both, the 10-membered rings adopt approximate chair-boat conformations. Their conformations are typical for heliangolides. The methyl group C14 is α, while the C-15 has a β-orientation. The α-methylene-γ-lactone istrans-fused at C6 and C7 with H6 β and H7 α. In compound2, the epoxide at C11–C13 has an α orientation.     

Structural features of 3d metal compounds with 1-hydroxyethylidenediphosphonic acid

Structural features of 3d metal complexes with anions of 1-hydroxyethylidenediphosphonic acid (HEDP, H₄ L), in which the M: HEDP ratios are equal to 1: 2, 1: 1, 3: 2, and 5: 2, are discussed. The Cu(II): HEDP = 1: 2 complexes are characterized by five types of structures: monomeric structures trans-[Cu(H_{4 ? n} L)₂(H₂O)₂]^{2 ? 2n} , cis-[Cu(H_{4 ? n} L)₂(H₂O)₂]^{2 ? 2n} , and [Cu(L)₂]^6?; the dimeric structure { [Cu(H₂ L)(H₂O)]₂(μ ₂-H₂ L)₂}^4? ; and the polymeric chain structure {[Cu(μ ₂-H₂ L)₂]^2?}_∞. Six coordination modes exhibited by HEDP in the Cu(II) compounds are described.     

Primary to secondary sphere coordination of 18-crown-6 to lanthanide (III) nitrates: Structural analysis of [Pr(NO3)3-(18-crown-6)] and [M(NO3)3(OH2)3]·18-crown-6 (M=Y,Eu, Tb−Lu)

The direct reaction of hydrated lanthanide nitrate salts with 18-crown-6 in 31 CH₃CNCH₃OH has resulted in the isolation and structural characterization of [Pr(NO₃)₃(18-crown-6)] and [M(NO₃)₃(OH₂)₃]·18-crown-6 (M=Y, Eu, Tb–Lu). (The Eu and Yb analogs were confirmed with preliminary cell data only.) [Pr(NO₃)₃(18-crown-6)] is 12-coordinate icosahedral and crystallizes in the orthorhombic space group Pbca with (at 20°C)a=12.230(2),b=15.598(4),c=21.777(9)Å andD _calc=1.89 g cm^–3 forZ=8. The seven isostructural [Pr(NO₃)₃(18-crown-6)] complexes all contain 9-coordinate capped square antiprismatic metal centers hydrogen bonded via the bound water molecules to D_3d 18-crown-6 within the lattice to form hydrogen bonded polymeric chains. Each complex is orthorhombic Pnma with cell parameters as follows: M=Tb (20°C):a=15.242(6),b=14.253(11),c=11.070(6)Å,D _calc=1.83 g cm^–3 forZ=4; M=Dy (20°C):a=15.248(3),b=14.239(5),c=11.058(3)Å,D _calc=1.84 g cm^–3 forZ=4; M=Y (19°C):a=15.260(2),b=14.238(2),c=11.048(3) Å,D _calc=1.64 g cm^–3 for Z=4; M=Ho (20°C):a=15.226(4),b=14.208(15),c=11.028(3)Å,D _calc=1.86 g cm^–3 forZ=4; M=Er (20°C):a=15.250(3),b=14.208(7),c=11.028(3)Å,D _calc=1.87 g cm^–3 forZ=4; M=Tm (20°C):a=15.246(6),b=14.190(16),c=11.013(6) Å,D _calc=1.88 g cm^–3 forZ=4; M=Lu (21°C):a=15.244(9),b=14.158(6),c=10.980(7)Å,D _calc=1.90 g cm^–3 forZ=4.     

Structure of chlorohydroxonitrosyl(terpyridine)ruthenium(II) hexafluorophosphate

The title complex has the NO grouptrans to the hydroxyl ligand and the chloride ion in the plane of the tripyridyl ligand. The Ru?O and Ru?N(O) distances are 1.939(5) Å and 1.764(6) Å, respectively; the Ru?N?O bond angle is 171.7(6)⁰. These values are consistent with previously reported shortening of Ru?O distances whentrans to a linear NO ligand. The space group of the structure isP2₁/c, witha=9.7213(9) Å,b=13.9318(11) Å,c=14.523(4) Å, and β=105.820(13)⁰.     

Structure of antitumor agents 2-acetylpyridinethiosemicarbazone hemihydrate and 2-acetylpyridinethiosemicarbazone hydrochloride

The structures of two antitumor agents, 2-acetylpyridinethiosemicarbazone hemihydrate (1), C₁₈H₁₁N₄O_0.5S, colorless,M _r 203.3, monoclinic,P2₁ lc,a=16.713(3),b=9.460(2),c=12.642(2) Å, β=97.60(1)°,V=1981.2(6) ų,Z=8,R=0.054,R _w =0.085 and 2-acetylpyridinethiosemicarbazone hydrochloride (2), C₁₈H₁₂N₄SCl, yellow,M _r =230.7, monoclinic,P2₁ ln,a=7.676(2),b=7.889(1),c=17.452(4), Å, β=100.96(2)°,V=1037.5(4) ų Z=4,R=0.041,R _w =0.076, have been determined. Both compounds exhibit an E configuration(S atomtrans to the N atom of the hydrazine group). Three hydrogen bonds link the two crystallographically independent molecules in a pairwise fashion in the hemihydrate. An intramolecular N?H...Cl bond lends extra conformational stability to the hydrochloride salt.     

Synthesis and crystal structure of (CN3H6)2[UO2(OH)2(NCS)]NO3 and β-Cs3[UO2(NCS)5]

Compounds (CN₃H₆)₂[UO₂(OH)₂(NCS)]NO₃ (I) and β-Cs₃[UO₂(NCS)₅] (II) are synthesized and studied by IR spectroscopy and single-crystal X-ray diffraction. I and II crystallize in the orthorhombic system. For I, a = 12.2015(13) Å, b = 7.3295(8) Å, c = 16.310(2) Å, space group Pnma, Z = 4, and R = 0.0327; for II, a = 21.7891(6) Å, b = 13.5120(3) Å, c = 6.8522(2) Å, space group Pnma, Z = 4, and R = 0.0268. In structure I, complex groups form infinite chains [UO₂(OH)₂(NCS)] _n ^n? belonging to the AM ₂ ² M ¹ crystal chemical group of uranyl complexes (A = UO ₂ ²⁺ , M ² = OH^?, and M ¹ = NCS^?). The main structural elements of crystals II are mononuclear [UO₂(NCS)₅]^3? groups belonging to the AM ₅ ¹ group of uranyl complexes (A = UO ₂ ²⁺ and M ¹ = NCS^?). In I and II, uranium-containing complexes are connected with outer-sphere cations by electrostatic interactions, and in I a system of hydrogen bonds also contributes to their binding. Specific features of the packing of complex [UO₂(NCS)₅]^3? groups in the structures of two modifications of Cs₃[UO₂(NCS)₅] are discussed.