A new binuclear germanium(IV) and copper(II) complex with 1,3-diamino-2-propanoltetraacetic acid: Crystal and molecular structure of [(H2O)(OH)Ge(μ-Hpdta)Cu(H2O)] · 3H2O

A heteronuclear germanium(IV) and copper(II) complex with 1,3-diamino-2-propanoltetraacetic acid (H₅Hpdta) has been synthesized for the first time. The compound has been characterized by elemental analysis, X-ray diffraction, thermogravimetry, and IR spectroscopy. The structure of the complex [(H₂O)(OH)Ge(μ-Hpdta)Cu(H₂O)] · 3H₂O (I) has been determined by single-crystal X-ray diffraction. The crystals of I are monoclinic, a = 1 5.327(4) Å, b = 11.626(3) Å, c =21.058(3) Å, β = 96.35(2)°, V = 3729.2(2) ų, Z = 8, space group C2/c, R1 = 0.0551 on 3090 reflections with I > 2σ(I). The structural units of the crystal of I are binuclear complex molecules [(H₂O)(OH)Ge(μ-Hpdta)Cu(H₂O)] and crystal water molecules. The germanium and copper atoms are linked by the bridging oxygen atom of the deprotonated isopropanol group of the Hpdta^5? ligand (Ge-O, 1.843(3) Å; Cu-O, 2.221(3) Å). The coordination spheres of the Ge and Cu atoms contain each one nitrogen atom (Ge-N, 2.090(4) Å; Cu-N, 2.000(4) Å) and two carboxyl oxygen atoms from four acetate arms of the heptadentate Hpdta^5? ligand (av. Ge-O, 1.909(3) Å; Cu-O, 1.948(3) Å). The coordination polyhedron of the Ge atom is completed to a distorted octahedron by the oxygen atoms of the terminal hydroxy group (Ge-O, 1.786(3) Å) and a water molecule (Ge-O, 1.904(3)Å). The coordination polyhedron of the copper atom is completed to a prolate tetragonal pyramid (4 + 1) by the oxygen atom of a water molecule in the equatorial position (Cu-O, 1.955(4) Å) and the bridging O(11) atom (Hpdta^5?) in the apical position. Binuclear molecules are linked pairwise in a head-to-head manner via double Cu-O(2) bridges to form the centrosymmetric tetranuclear supramolecule {[(H₂O)(OH)Ge(μ-Hpdta)Cu(H₂O)]}₂. The coordination of the Cu atom is completed by the weak Cu-O(2A) contact (3.303 Å) to an asymmetrically elongated tetragonal bipyramid (4 + 1 +1). In the crystal, the complex molecules and crystal water molecules are combined by a system of hydrogen bonds into a three-dimensional framework.     

Copper(II) complex of the chelating agent EDTA bis(tyrosine)

The synthesis technique is given and the results of X-ray study of a copper(II) compound, Cu(O₁₂N₄C₂₈H₃₀)·7H₂O, are reported. The structure is molecular and the copper atom is coordinated by a distorted octahedron exhibiting a Jahn-Teller effect. The Cu-O(carbonyl) bond is 0.31 Å longer than the axial carboxylate to copper bonds.     

Synthesis,crystal structures and properties of three glutarato and adipato bridged manganese(II) coordination polymers under ambient conditions

Three Mn(II) polymers Mn(H₂O)₄(C₅H₆O₄) 1, [Mn(H₂O)₂(C₅H₆O₄)]·H₂O 2 and Mn(H₂O)(C₆H₈O₄) 3 were synthesized (H₂(C₅H₆O₄) = glutaric acid, H₂(C₆H₈O₄) = adipic acid) under mild ambient conditions. The [Mn(H₂O)₂]²⁺ units in 2 are interlinked by the glutarate anions with a η⁴μ₃ bridging mode to form 2D (4·8²) topological networks, which are stacked via interlayer hydrogen bonds into a 3D (4³·6⁵·8²)(4⁷·6³) topological net. Compound 3 crystallizes in the acentric space group P2₁ and exhibits significant ferroelectricity (remnant polarization Pr = 0.371 nC cm⁻², coercive field Ec = 0.028 kV cm⁻¹, saturation of the spontaneous polarization Ps = 0.972 nC cm⁻²). The adjacent MnO₆ octahedrons in 3 are one atom-shared to generate the Mn₂O₁₁ bi-octahedron, leading into 1D metal oxide chains. The resulting chains are interconnected by the η⁵μ₅ adipate anions to form new 2D (4⁸·6²) networks, which are held together via strong interlayer hydrogen bonds into 3D α-Po topological supra-molecular architecture. The temperature-dependent magnetic susceptibility data of 1–3 shows overall anti-ferromagnetic interactions between the metal ions bridged by the carboxylate groups.     

Crystal structure of hexaaqua(isocyanurato-O)calcium isocyanurate monohydrate

Crystals of [Ca(C₃H₂N₃O₃)(H₂O)₆]⁺ · (C₃H₂N₃O₃)^? · H₂O (I) are restudied by X-ray crystallography. The previous X-ray study is shown to be incorrect. The crystal structure of I (space group $P\bar 1$ , a = 6.503 Å, b = 10.830 Å, c = 11.824 Å, α = 103.58°, β = 92.64°, γ = 98.82°, Z = 2) is solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.037 for 2792 independent reflections (CAD4 automated diffractometer, λMoK _α radiation). In the [Ca(C₃H₂N₃O₃)(H₂O)₆]⁺ complex cation, the coordination polyhedron of the Ca atom is a strongly distorted octahedron with one additional vertex. The crystal of I contains a developed three-dimensional system of interionic (intermolecular) hydrogen bonds involving all H atoms.     

Nanocomposites with the layered structure of V2O5 · nH2O xerogel

New layered nanocomposites of V₂O₅ · nH₂O xerogels with poly(vinyl alcohol) (PVA), pyrocatechol (PC), and hydroquinone (HQ) were synthesized with the compositions (C₂H₃)_0.32V₂O_4.90 · nH₂O, (C₆H₄)_xV₂O_4.60 · nH₂O, and (C₆H₄)_0.17V₂O_4.94 · nH₂O and the interlayer distances d ₀₀₁ = 11.73, 12.85, and 15.28 ± 0.05 Å, respectively. IR and Raman spectroscopy was used to analyze which structural changes occur in the V-O layers of the xerogel upon composite formation. X-ray photoelectron spectroscopy showed V⁴⁺ and V⁵⁺ ions in the layers with binding energies lower than in V₂O₅ · nH₂O. The electrical conductivity of the nanofilms and the thermal properties of the nanopowders were studied.     

Two Light-Metal Dihydrogenisocyanurate Hydrates Linked by Diagonal Relationship: Syntheses,Crystal Structures,and Vibrational Spectra of Li[H2N3C3O3]·1.75 H2O and Mg[H2N3C3O3]2·8 H2O

Single-crystalline materials of Li[H₂N₃C₃O₃] · 1.75 H₂O and Mg[H₂N₃C₃O₃]₂ · 8 H₂O were obtained by dissolving stoichiometric amounts of the respective carbonates with cyanuric acid in boiling water followed by gentle evaporation of excess water after cooling to room temperature. Even though both of these compounds crystallize in the triclinic space group P1 according to X-ray structure analyses of their colorless and transparent single crystals, they adopt two new different structure types. Li[H₂N₃C₃O₃] · 1.75 H₂O exhibits the unit-cell parameters a = 884.71(6) pm, b = 905.12(7) pm, c = 964.38(7) pm, α = 67.847(2)°, β = 62.904(2)° and γ = 68.565(2)° (Z = 4), whereas the lattice parameters for Mg[H₂N₃C₃O₃]₂ · 8 H₂O are a = 691.95(5) pm, b = 1055.06(8) pm, c = 1183.87(9) pm, α = 85.652(2)°, β = 83.439(2)° and γ = 79.814(2)° (Z = 2). In both cases, the singly deprotonated isocyanuric acid forms monovalent anions consisting of cyclic [H₂N₃C₃O₃]^– units, which are arranged in ribbons typical for most hitherto known monobasic isocyanurate hydrates. The structures are governed by the oxophilic strength of the respective cation which means that they fulfil their oxophilic coordination requirements either solely with water molecules ([Mg(OH₂)₆]²⁺ for Mg²⁺) or with crystal water and one or two direct coordinative contacts to carbonyl oxygen atoms (O_(cy)) of [H₂N₃C₃O₃]^– anions ([(Li(OH₂)_2–3(O_(cy)1–2]⁺ for Li⁺). In both structures occur dominant hydrogen bonds N–H ··· O within the anionic [H₂N₃C₃O₃]^– ribbons as well as hydrogen bonds O–H ··· O between these ribbons and the hydrated Li⁺ and Mg²⁺ cations.     

Syntheses and Spectroscopic Study of Some New N‐4‐Fluorobenzoyl Phosphoric Triamides; Crystal Structures of 4‐F‐C6H4C(O)N(H)P(O)R2, R = NH‐C(CH3)3, NH‐CH2C6H5, N(CH3)(CH2C6H5)

Some new N‐4‐Fluorobenzoyl phosphoric triamides with formula 4‐F‐C₆H₄C(O)N(H)P(O)X₂, X = NH‐C(CH₃)₃ ( 1 ), NH‐CH₂‐CH=CH₂ ( 2 ), NH‐CH₂C₆H₅ ( 3 ), N(CH₃)(C₆H₅) ( 4 ), NH‐CH(CH₃)(C₆H₅) ( 5 ) were synthesized and characterized by ¹H, ¹³C, ³¹P NMR, IR and Mass spectroscopy and elemental analysis. The structures of compounds 1 , 3 and 4 were investigated by X‐ray crystallography. The P=O and C=O bonds in these compounds are anti. Compounds 1 and 3 form one dimensional polymeric chain produced by intra‐ and intermolecular ‐P=O···H‐N‐ hydrogen bonds. Compound 4 forms only a centrosymmetric dimer in the crystalline lattice via two equal ‐P=O···H‐N‐ hydrogen bonds. ¹H and ¹³C NMR spectra show two series of signals for the two amine groups in compound 1 . This is also observed for the two α‐methylbenzylamine groups in 5 due to the presence of chiral carbon atom in molecule. ¹³C NMR spectrum of compound 4 shows that ²J(P,C_aliphatic) coupling constant for CH₂ group is greater than for CH₃ in agreement with our previous study. Mass spectra of compounds 1 ‐ 3 (containing 4‐F‐C₆H₄C(O)N(H)P(O) moiety) indicate the fragments of amidophosphoric acid and 4‐F‐C₆H₄CN⁺ that formed in a pseudo McLafferty rearrangement pathway. Also, the fragments of aliphatic amines have high intensity in mass spectra.     

Synthesis and vibrational spectra of copper(II) and erbium(III) complexes with 2-[2′-(oxymethyldiphenylphosphinyl)phenyldiazenyl]-4- tert -butylphenol (HL) [CuL2] · 2H2O and Er(NO3)2 · 2 HL · 2H2O. Crystal structure of [CuL2] · 2H2O

The syntheses of the complex copper salt CuL₂ · 2H₂O (I) and the erbium nitrate complex Er(NO₃)₃ · 2HL · 2H₂O (II) (HL is 2-[2′-(oxymethyldiphenylphosphinyl)phenyldiazenyl]-4-tert-butylphenol) have been described. Basic vibrational frequencies in the IR spectra of I and II have been interpreted. The crystal structure of I has been determined by X-ray crystallography: the crystals are monoclinic, a = 15.157(3) ?, b = 17.080(2) ?, c = 22.451(9) ?, β = 106.09(3)°, V = 5584(3) ?³, Z = 4, space group C2/c, R = 0.0546 (for 1152 reflections with I > 2σ(I)). The coordination polyhedron of the copper atom (symmetry C ₂) can be described as a symmetrically elongated square bipyramid (4+2). The basic square of the Cu polyhedron is formed by the oxygen atom of the substituted phenol and one of the nitrogen atoms of the azo group of each of the two deprotonated ligands L⁻ (Cu-N, 1.969(6) ?; Cu-O, 1.899(5) ?). The angles between the opposite O and N atoms are 157.6°, and the other equatorial angles are in the range 90.6°–95.9°. The axial positions are occupied by the anisole O(2) and O(2A) atoms (Cu-O, 2.737(6) ?, the O(2)Cu(1)O(2A) angle, 132.3°). In the crystal of I, complex molecules and water molecules of crystallization are combined by a system of hydrogen bonds. IR spectra show that, in complex II, as distinct from compound I, the HL ligand is coordinated to the erbium atom through the phosphoryl oxygen atom. Original Russian Text ? A.Yu. Tsivadze, L.Kh. Minacheva, I.S. Ivanova, V.E. Baulin, E.N. Pyatova, V.S. Sergienko, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 4, pp. 601–607.     

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.     

Modification of supramolecular assemblies based on C4H7(CH3)Te heterocycle and cooperative participation of intermolecular I···I, Te···I, Te···O secondary bonds; C(sp3)–H···O and C(sp2)–H···O hydrogen bonds

2-Methyl-1,1-dicarboxylato-1-telluracyclopentanes C₄H₇(CH₃)Te(OCOR)₂ (R=OCO, C₆H₅, 4-NO₂C₆H₄, 3,5-(NO₂)₂C₆H₃, C₆H₅CH=CH, 4-OCH₃C₆H₄) (2–7) were synthesised from the reactions of 2-methyl-1,1-diiodo-1-telluracyclopentane (1) and corresponding silver salts and characterised by (IR &¹HNMR) spectroscopy. The structures of C₄H₇(CH₃)TeI₂ (1), C₄H₇(CH₃)Te(OCOC₆H₅)₂ (3) and C₄H₇(CH₃)Te(4-NO₂C₆H₄OCO)₂ (4) were established by single crystal X-ray diffraction studies. The structures of 1, 3 & 4 (the immediate environment about tellurium is that of distorted trigonal bipyramidal geometry with a stereochemically active electron lone pair) are described in the context of their ability to generate intermolecular I···I, Te···I, Te···O secondary bonds; C(sp³)–H···O and C(sp²)–H···O hydrogen bonds leading to the formation of polymeric, tetrameric and trimeric supramolecular assemblies. The modification of supramolecular assembly present in the precursor 1 is demonstrated and the cooperative participation of C(sp²)–H···O & C(sp³)–H···O hydrogen bonds, probably, helpful in strengthening the supramolecular assembly is discussed.

Analytical applications of the reaction of thorium with benzenephosphonic acid

Benzenephosphonic acid quantitatively precipitates thorium as Th(C₆H₅PO₃)₂·3H₂O at pH values as low as 0.5. The compound may be dried at 140° to 180° C and weighed, as a gravimetric means of determining thorium. On ignition, Th (C₂H₅PO₃)₂ 3 H₂O undergoes decomposition at 240° to 300° C to form Th(C₆H₅PO₃)₂·2H₂O, at 450° to 650° C to form Th(HPO₄)₂·2H₂O and finally at 800° to 1000° C to form Th(HPO₄)₂. The latter compound is stable to 1200° C.Potentiometrically (pK₁' = 0.91, pK₂' = 6.41) and spectrophotometrically (pK₁' = 0.96, pK₂' = 6.51) determined pK' values are reported. Absorption spectra of C₆H₅PO₃H₂, C₆H₅PO₃H^- and C₆H₅PO₃^-2 are reported. The solubility of Th (C₆H₅PO₃)₂·3H₂O was studied as a function of pH and the average value of the solubility product (K_sp = 4s³) was found to be 3.24·10^-31.     

New Mixed Ligand Copper(II) Complexes: Syntheses and Crystal Structures of Cu(Imid)2(H2O)L with Imid = Imidazole,L = Succinic and Fumaric Anions

Reactions of freshly prepared Cu(OH)_2—2x(CO₃)_x · yH₂O and imidazole (Imid) with succinic acid and fumaric acid, respectively, in CH₃OH/H₂O yields Cu(Imid)₂(H₂O)L with L = (C₄H₄O₄)^2— ( 1 ) and (C₄H₂O₄)^2— ( 2 ). Both isostructural complexes consist of 1D [Cu(Imid)₂(H₂O)L_2/2] polymeric chains, in which the T‐shaped [Cu(Imid)₂(H₂O)]²⁺ moieties are bridged by bis‐monodentate dicarboxylato ligands. Through the interchain hydrogen bonds between the coordinating H₂O molecule and the non‐coordinating carboxylate O atom, the polymeric chains are assembled into 2D layers, which are further assembled via interlayer N—H···O hydrogen bonds between imidazole N atom and the coordinating carboxylato O atom. Thermal analyses of 1 under N₂ stream showed that dehydration is immediately followed by decomposition of the anhydrous “Cu(Imid)₂(C₄H₄O₄)” intermediate into imidazole and “Cu(C₄H₄O₄)”. Upon further heating, sublimation of imidazole is followed by dissociation of the resulting “Cu(C₄H₄O₄)” into CO, CO₂, C₂H₄ in gaseous phase and solid CuO as residue. Crystal data: ( 1 ) C2/c (no. 15), a = 13.712(2), b = 5.589(1), c = 17.517(2)Å, β = 105.76(1)°, U = 1292.0(3)ų, Z = 4; ( 2 ) C2/c (no. 15), a = 13.758(2), b = 5.501(1), c = 17.464(2)Å, β = 106.05(2)°, U = 1270.2(3)ų, Z = 4.     

Synthesis, crystal structures, and magnetic properties of a new nickel(II) complex with nitronyl nitroxide

A new nickel(II) complex [Ni(NIT-1′-MeBzIm)₂(H₂O)₂] · ClO₄ · H₂O (NIT-1′-MeBzIm = 2-{2′-[(l′-methyl)benzimidazolyl]}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) has been prepared and structurally characterized by single-crystal X-ray diffraction. Complex I crystallizes in monoclinic, space group C2/c, Z = 4. Crystal data: C₃₀H₄₆N₈O₁₆ClNi, Mr = 869.06, a = 13.958(3), b = 15.904(4), c = 18.514(5) Å, β = 101.047(3)°. The X-ray analysis reveals that Ni²⁺ ion resides in a distorted octahedron center, the complex was linked by intermolecular hydrogen bonds, resulting in a 2D network configuration. Magnetic investigation indicates the existence of interamolecular interactions is antiferromagnetic with J = ?40.76 cm^?1.     

Structure of bis(hexamethylenetetramine) hexaaquanickel(II)hexafluorotitanate(IV) monohydrate — [Ni(OH2)6][TiF6](Ur)2·H2O

The X-ray diffraction study of a single crystal with the composition NiTiF₆(Ur)₂·7H₂O is performed, where Ur = C₆H₁₂N₄ is an urotropine (hexamethylenetetramine) molecule. The compound crystallizes in the triclinic P-1 space group: a = 8.7220(5) Å, b = 9.1004(5) Å, c = 17.533(1) Å, α = 75.074(1)°, β = 88.530(1)°, γ = 62.558(1)°, Z = 2, d _x = 1.756 g/cm³, μ = 1.228 mm^?1, R = 0.0351. The crystalline compound is ionic. The structural unit consists of [Ni(OH₂)₆]²⁺ and [TiF₆]^2? ions and Ur and H₂O molecules. The structural formula of the compound is [Ni(OH₂)₆][TiF₆](Ur)₂·H₂O. Hydrogen bonds in the compound are studied and analyzed.     

Structure and spectral characteristics of (NH4)2[Re2(HPO4)4 · 2H2O]

The compound (NH₄)₂[Re₂(HPO₄)₄ · 2H₂O] has been synthesized and characterized by electronic and vibrational spectroscopy. The molecular structure has been determined by X-ray diffraction (MoK _α radiation, λ = 0.71073 Å). The (NH₄)₂[Re₂(HPO₄)₄ · 2H₂O] coordination units form centrosymmetrical binuclear ordering with each metal atom being coordinated in a distorted octahedron incorporating one rhenium atom, one oxygen atom of the water molecule, and four phosphate oxygen atoms in the equatorial plane. The rhenium-rhenium bond length (2.2207 Å) corresponds to a quadruple bond between the atoms. The [Re₂(HPO₄)₄ · 2H₂O]^2- complex anions in the crystal are associated through strong hydrogen bonds formed by the phosphate O-H···O groups. The stability of dirhenium(III) tetra-μ-phosphates in aqueous solutions is considered.     

2‐Aminopyridinium–succinate–succinic acid (2/1/1)

In the title compound, 2C₅H₇N₂⁺·C₄H₄O₄^2?·C₄H₆O₄, cyclic eight‐membered hydrogen‐bonded rings exist involving 2‐amino­pyridinium and succinate ions. The succinic acid and succinate moieties lie on inversion centres. Succinic acid mol­ecules and succinate ions are linked into zigzag chains by O—H?O hydrogen bonds, with O?O distances of 2.6005 (16) Å.     

Crystal structure of bis[Ba(Aet)(OH2)5]bis(Aet)·4H2O

An X-ray crystallographic study is conducted of single crystals with the composition [Ba₂(Aet^?)₂·10(H₂O)]²⁺·2(Aet^?)·4H₂O, where Aet^? = (C₁₀H₁₁N₄O₂S₂)^? is the ethazole (2-(para-aminobenzenesulfamido)-5-ethyl-1,3,4-tiadiazole) anion. The crystals are monoclinic; the space group is P2₁/c, Z = 2; a = 9.793(2) Å, b = 15.408(4) Å, and c = 22.553(6) Å; β = 94.98(2)°; and R = 0.047. The independent part of the compound’s structural formula, [Ba(Aet)(OH₂)₅](Aet)·2H₂O, is isostructural with the analogous compound with the Sr atom. The ethazole anion is coordinated to the complexing metal atom by oxygen and nitrogen atoms to form a four-membered ring.     

Uncommon hydrogen bonds between a non-classical ethyl cation and π hydrocarbons: a preliminary study

This study undertakes a theoretical investigation into uncommon hydrogen bonds between the ethyl cation (C₂H₅ ⁺) and π hydrocarbons. Firstly, it considers the hyperconjugation effect of the ethyl cation, in which the non-localized hydrogen (H⁺) is taken to be a pseudoatom bound to the carbons of the methyl groups. The goal of the research is to use this electronic phenomenon to gain a better understanding of the (H⁺···π) and (H⁺···p-π) hydrogen bonds, which are considered uncommon because they are formed through the interaction of the H⁺ of the ethyl cation with the π bonds of the acetylene (C₂H₂) and ethene (C₂H₄), as well as with the pseudo-π bond of the cyclopropane (C₃H₆). In view of this, B3LYP/6-311++G(d,p) calculations were used to determine the geometries of the C₂H₅ ⁺···C₂H₂, C₂H₅ ⁺···C₂H₄, and C₂H₅ ⁺···C₃H₆ hydrogen-bonded complexes. Deformations of the bond lengths and bond angles of these systems were analyzed geometrically. Examination of the stretch frequencies and absorption intensities of the (H⁺···π) and (H⁺···p-π) hydrogen bonds has revealed red-shifts in π and p-π bonds. After structural modeling and vibrational characterization, analysis of the charge transfer following the ChelpG approach and subsequently quantification of the hydrogen bond energies (basis sets superpostition error and zero point vibrational energies being considered) were used to predict the strength of the (H⁺···π) and (H⁺···p-π) hydrogen bonds. In addition, the molecular topography was estimated using the quantum theory of atoms in molecules (QTAIM). QTAIM was chosen because of a desire to understand the (H⁺···π) and (H⁺···p-π) hydrogen bonds chemically on the basis of the quantity of charge density and interpretation of Laplacian fields. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Synthesis and study of cobalt(II), nickel(II), and copper(II) complexes with 4-(4-hydroxyphenyl)-1,2,4-triazole

New complexes of Co(II), Ni(II), and Cu(II) nitrates, chlorides, and perchlorates with 4-(4-hydroxyphenyl)-1,2,4-triazole (L) were obtained and examined by single-crystal X-ray diffraction, X-ray powder diffraction, and electronic absorption and IR spectroscopy. The cations of all the complexes have linear trinuclear structures. Ligand L is coordinated to the metal ions in a bidentate bridging fashion through the N(1) and N(2) atoms of the heterocycle. The coordination polyhedron of the metal atoms is a distorted octahedron. The molecular and crystal structures of the complexes [Co₃L₆(H₂O)₆](ClO₄)₆ · 3C₂H₅OH · 3.75H₂O and [M₃L₆(H₂O)₆](ClO₄)₆ · 6H₂O (M = Cu²⁺ and Ni²⁺) were determined.     

Synthesis and crystal structure of dibenzo-18-crown-6 oxonium perchlorate trihydrate

A hydrated crystalline ionized adduct of dibenzo-18-crown-6 and perchloric acid DB18C6 · H₃O⁺ · CiO ₄ ^? · 3H₂O (I) is synthesized and characterized by X-ray diffraction. The crystals of I are monoclinic: a = 17.760 Å, b = 12.922 Å, β = 124.27°, Z = 4, space group Cc. The structure of I is solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.079 for 3294 independent reflections (CAD4 automated diffractometer, λMoK _α radiation). A DB18C6 molecule has a butterfly conformation with the rough symmetry C _2v . An H₃O⁺ · H₂O dimer is situated on one side of the DB18C6 macrocycle, and the ClO ₄ ^? anion and two other water molecules are on the other side. In the crystal of I, the DB18C6 molecules, H₃O⁺ and ClO ₄ ^? ions, and water molecules are linked through intermolecular (interionic) hydrogen bonds to form broad infinite chains running along the z axis.