Synthesis and structural characterization of a novel tetranuclear Cu(II) complex: [Cu<Subscript>4</Subscript>L<Subscript>2</Subscript>(pic)<Subscript>4</Subscript>(H<Subscript>2</Subscript>O)<Subscript>2</Subscript>]·2H<Subscript>2</Subscript>O

A novel Salen-type bisoxime ligand, 6,6′-dimethoxy-2,2′-[(1,4-butylene)dioxybis(nitrilomethylidyne)]diphenol (H₂L) and its tetranuclear Cu(II) complex, [Cu₄L₂(pic)₄(H₂O)₂]·2H₂O, have been synthesized and characterized by elemental analyses, IR, TG-DTA and ¹H-NMR etc. The X-ray crystal structure of the complex reveals that formation of a tetranuclear structure, which consists of four copper(II) atoms, two pentadentate L²⁻units, four picratols, two coordinated water molecules and two crystallizing water molecules. Around four copper ions are all octahedral geometries. It was demonstrated that the picratols in the tetranuclear copper(II) complex show a novel tridentate coordination mode.     

Synthesis and Structure of [Co(NH<Subscript>3</Subscript>)<Subscript>6</Subscript>]<Subscript>2</Subscript>[W<Subscript>4</Subscript>Se<Subscript>4</Subscript>(CN)<Subscript>12</Subscript>]·8.5H<Subscript>2</Subscript>O

The compound [Co(NH₃)₆]₂[W₄Se₄(CN)₁₂]·8.5H₂O was obtained by evaporating an aqueous ammonia solution of K₆[W₄Se₄(CN)₁₂]·6H₂O and CoCl₂·6H₂O complexes. The starting Co(II) of CoCl₂·6H₂O transforms into [Co(NH₃)₆]³⁺ when exposed to air in a water-ammonia medium. Crystal data: triclinic crystal system, a = 10.7750(8) Å, b = 12.2843(9) Å, c = 19.6539(14) Å; α = 90.213(2)°, β = 99.910(2)°, γ = 114.737(1)°, V = 2319.1(3) ų, space group , Z = 2, D _x = 2.633 g/cm³.Original Russian Text Copyright © 2004 by I. V. Kalinina, Z. A. Starikova, F. M. Dolgushin, D. G. Samsonenko, and V. P. Fedin__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 5, pp. 905–908, September–October, 2004.     

Kinetics and thermodynamics of thermal decomposition of NH<Subscript>4</Subscript>NiPO<Subscript>4</Subscript>·6H<Subscript>2</Subscript>O

The single phase NH₄NiPO₄·6H₂O was synthesized by solid-state reaction at room temperature using NiSO₄·6H₂O and (NH₄)₃PO₄·3H₂O as raw materials. XRD analysis showed that NH₄NiPO₄·6H₂O was a compound with orthorhombic structure. The thermal process of NH₄NiPO₄·6H₂O experienced three steps, which involves the dehydration of the five crystal water molecules at first, and then deamination, dehydration of the one crystal water, intramolecular dehydration of the protonated phosphate groups together, at last crystallization of Ni₂P₂O₇. In the DTA curve, the two endothermic peaks and an exothermic peak, respectively, corresponding to the first two steps’ mass loss of NH₄NiPO₄·6H₂O and crystallization of Ni₂P₂O₇. Based on Flynn–Wall–Ozawa equation, and Kissinger equation, the average values of the activation energies associated with the thermal decomposition of NH₄NiPO₄·6H₂O, and crystallization of Ni₂P₂O₇ were determined to be 47.81, 90.18, and 640.09 kJ mol⁻¹, respectively. Dehydration of the five crystal water molecules of NH₄NiPO₄·6H₂O, and deamination, dehydration of the crystal water of NH₄NiPO₄·H₂O, intramolecular dehydration of the protonated phosphate group from NiHPO₄ together could be multi-step reaction mechanisms. Besides, the thermodynamic parameters (ΔH ^≠, ΔG ^≠, and ΔS ^≠) of the decomposition reaction of NH₄NiPO₄·6H₂O were determined.     

Crystal structure of Cs[Gd(H<Subscript>2</Subscript>O)<Subscript>4</Subscript>Re<Subscript>6</Subscript>Te<Subscript>8</Subscript>(CN)<Subscript>6</Subscript>]·4H<Subscript>2</Subscript>O

The structure of the salt Cs[Gd(H₂O)₄Re₆Te₈(CN)₆]·4H₂O (space group P-1, a = 9.436(5) Å, b = 12.365(7) Å, c = 15.187(8)Å, α = 89.104(10)°, β = 86.996(10)°, γ = 82.304(9)°) has been established by single crystal XRD. The structure of the compound features layers involving Gd³⁺ cations bound to cluster anions [Re₆Te₈(CN)₆]^4? through cyanide groups. The interlayer space contains cesium cations and crystallization water molecules.     

Synthesis and crystal structure of complex [Mn(Imdc)<Subscript>2</Subscript>(H<Subscript>2</Subscript>O)<Subscript>2</Subscript>] · 2H<Subscript>2</Subscript>O and its interaction with DNA

Under hydrothermal conditions, the complex [Mn(lmdc)₂(H₂O)₂] · 2H₂O (I) was synthesized and characterized by elemental analysis and IR spectrum (HImdc = 4,5-imidazofedicarboxylic acid). The crystal structure of I was determined by single-crystal X-ray diffraction (crystallizing in the monoclinic crystal system, P ₂/c space group, a = 11.000(2), b = 7.1281(14), c = 12.696(3) Å, β = 122.45(3), Z = 2. In I, the Mn²⁺ ion was chelated by two Imdc with one of their nitrogen atoms and a carboxylic oxygen atom, while two water molecules occupy the axial position of the Mn atom forming a distorted octahedral geometry. Three-dimensional structure of I was formed by intermolecular hydrogen bonds. UV-Vis and fluorescence spectra of I interacting with DNA show that insertion is the main binding mode between I and fish sperm DNA. Gel electrophoresis shows that I cleaves both supercoiled and circular pBR322 DNA to form a small molecular fragment.     

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.     

New double complex salt [PdEn<Subscript>2</Subscript>]<Subscript>3</Subscript>[Rh(NO<Subscript>2</Subscript>)<Subscript>6</Subscript>]<Subscript>2</Subscript> · 2.67H<Subscript>2</Subscript>O: Synthesis,crystal structure,and thermal properties

The crystal structure of the double complex salt (DCS) [PdEn₂]₃[Rh(NO₂)₆]₂ ? 2.67H₂O (I) has been determined by X-ray diffraction. Crystals are triclinic, space group \(P\bar 1\), Z = 4, a = 9.2331(3) Å, b = 9.9136(4) Å, c = 13.7824(5) Å, α = 84.3230(14)°, β = 89.9655(14)°, γ = 66.7272(13)°, V = 1152.19(7) ų, ρ_calcd = 2.141 g/cm³, R = 0.0279. The thermal behavior of complex salt I has been studied in various gas atmospheres. The end product of thermolysis in reductive atmosphere is a mixture of Pd_0.45Rh_0.55 and Pd_0.95Rh_0.05 solid solutions. The end product of thermolysis in an inert atmosphere is a homogeneous Pd_0.6Rh_0.4 solid solution.     

Motif of the three-layered close packing of cluster anions in [RhPy<Subscript>4</Subscript>Cl<Subscript>2</Subscript>]<Subscript>4</Subscript>[Re<Subscript>6</Subscript>S<Subscript>8</Subscript>(CN)<Subscript>6</Subscript>]·1.5H<Subscript>2</Subscript>O

[RhPy₄Cl₂]₄[Re₆S₈(CN)₆]·1.5H₂O (Py is pyridine) was investigated by X-ray analysis. In the cluster anion, the Re-Re distances vary from 2.6063(2) Å to 2.6125(2) Å. For two crystallographically independent complex cations, the distances are 〈Rh-N〉 2.060 Å and 〈Rh-Cl〉 2.336 Å. The motif of the three-layered close packing was found; the [Re₆S₈(CN)₆]^4? anions follow the vertices of a rhombohedron with the parameters a _c ≈ 15.5 Å and α_c ≈ 61°.     

Structure and thermal decomposition of Cs<Subscript>2</Subscript>HPO<Subscript>4</Subscript> · 2H<Subscript>2</Subscript>O

The thermal transformations of disubstituted cesium orthophosphate crystal hydrate under heating in air up to 400°C have been studied. The dehydration process occurs in two stages with the loss of 0.6 water molecules at 60?100°C and 1.4 water molecules at 100?160°C. Anhydrous Cs₂HPO₄ is stable up to 300°C and is completely converted into cesium pyrophosphate Cs₄P₂O₇ at 330°C. The structure of Cs₂HPO₄ · 2H₂O has been determined. The compound crystallizes in monoclinic space group P2₁/c and has the unit cell parameters a = 7.4761(5) Å, b = 14.2125(8) Å, c = 7.9603(6) Å, β = 116.914(5)°, V = 754.20(9) ų, and Z = 4 at?123°C. An earlier unknown polymorph of Cs₄P₂O₇ has been found. According to X-ray powder diffraction data, hexagonal space group Р6₃ has been proposed for the formed pyrophosphate.     

Structural regularities of the ionic complex [K(18C6)]<Subscript>3</Subscript>[In(NCS)<Subscript>6</Subscript>] · 2H<Subscript>2</Subscript>O

The associate [K(18C6)]₃[In(NCS)₆] · 2H₂O was synthesized and structurally characterized. The structure was formed by the octahedral anions [In(NCS)₆]³⁻, crystallographically independent cations [K(18C6)]⁺, and molecules of water of crystallization. The complex anion and one of the two cations formed polymeric chains (-In-NCS-K-) _n . The second cation coordinated one of the sulfur atoms of the polymer chain.     

Crystal structure and quantum chemical investigation of [Cd(NTO)<Subscript>4</Subscript>Cd(H<Subscript>2</Subscript>O)<Subscript>6</Subscript>] · 4H<Subscript>2</Subscript>O

[Cd(NTO)₄Cd(H₂O)₆] •4H₂O was synthesized by mixing the aqueous solution of 3-nitro-1, 2,4-triazol-5-one (NTO) and cadmium carbonate. The single crystal structure was determined by a four-circle X-ray diffractometer. The crystal is monoclinic, space group C2/c with crystal parameters of a = 2.1229(3) nm, b = 0.6261(8) nm, = 2.1165(3) nm, β= 90.602 (3)°, V= 2.977(6) nm₃, Z = 4, D_c = 2.055 g • cm_-3, μ = 15.45 cm_-1 and F(000) = 1824. 2523 observable independent reflections with F₀4σ(F₀) were used for the determination and refinement of the crystal structure. Lorentz-polarization and absorption correction were applied. The final R is 0.0282 and wR = 0.0792. The analytical results show that the Cd⁺² has two kinds of coordinate bonds in one crystal. One Cd⁺² coordinates with 4 NTO anions and another coordinates with 6 water molecules to form a binucleate complex with a structure of tetrahedron and tetragonal bipyramid, respectively. By using SCF-PM3-MO method, the electron structure of cadmium complex of NTO has been calculated. The analysis of the calculated results shows that when [Cd(NTO)₄Cd(H₂O)₆] • 4H₂O is heated, the crystallization waters will be dissociated first and the ligand waters second and NO₂ group has priority of leaving when NTO⁻ is decomposed. Analysis of the energy level and composition of localized molecular orbitals indicates that both the two Cd²⁺ bond to the coordinating atom with 5s     

Synthesis,crystal structure and DNA-binding studies of the complex [Co(C<Subscript>10</Subscript>H<Subscript>9</Subscript>N<Subscript>2</Subscript>O<Subscript>4</Subscript>)<Subscript>2</Subscript>] · 3H<Subscript>2</Subscript>O

A novel binuclear Cobalt(II) complex with N-(2-propionic acid)-salicyloyl hydrazone (C₁₀H₁₀N₂O₄, H₃L) was prepared and characterized. The crystal structure of [Co(C₁₀H₉N₂O₄)₂] · 3H₂O was determined by X-ray single-crystal diffractometry. The Co²⁺ ion is six-coordinated by the carboxyl and acyl O atoms and azomethine N atoms of two tridentate N-(2-propionicacid)-salicyloyl hydrazone ligands, which form two stable five-numbered rings sharing one side in the keto form. The coordination environment around the Co²⁺ ion might be described as a distorted octahedron. Abundant hydrogen bonds of the types O-H…N and O-H…O between the water molecules and ligands not only form the three-dimensional network, but also provide an extrastability for the crystal. The complex was studied for the interaction with calf thymus DNA by electronic absorption titration and emission titration. The results show that the complex is bound to calf thymus DNA mainly by intercalation. The article is published in the original.     

Synthesis and structure of the [Co(NioxH)<Subscript>2</Subscript>(Thio)<Subscript>2</Subscript>]<Subscript>2</Subscript>SO<Subscript>4</Subscript>·2H<Subscript>2</Subscript>O complex compound

A new Co(III) complex of 1,2-cyclohexanedionedioxime and thiocarbamide with an SO ₄ ^2? anion and solvation water molecules in the outer sphere has been synthesized and its structure has been defined. Orthorhombic crystals, a = 11.659(2) Å, b = 26.448(5) Å, c = 30.142(6) Å, V = 9295(3) Å ³, Z = 8, d_calc = 1.599 g/cm³, space group Pbca; final R index is 0.0578 for 8221 reflections with I > 2σ(I). In the octahedral Co(III) complex, two 1,2-cyclohexanedionedioxime residues lie in the equatorial plane, while two thiocarbamide molecules are in the axial plane. Intramolecular bonds: N-H…O and O-H…O type hydrogen bonds and π-π interactions that stabilize the complex cations. In crystal, the components are linked by N-H…O and O-H…O hydrogen bonds into a 3D framework.     

Synthesis and thermal properties of Co<Subscript>2</Subscript>P<Subscript>2</Subscript>O<Subscript>7</Subscript> · 6H<Subscript>2</Subscript>O

The dependence of solid phase composition on the main parameters of the interaction in the CoSO₄-K₄P₂O₇-H₂O system was studied. The synthesis conditions were determined and a crystalline cobalt(II) diphosphat of the composition Co₂P₂O₇ · 6H₂O was synthesized. Its thermal properties were studied. The composition and the intervals, wherein the thermally stable products of partial and complete dehydration of Co₂P₂O₇ · 6H₂O are formed, were specified. The final heat treatment product, anhydrous α-Co₂P₂O₇, was identified and a sequence of the solid phase thermal transformations accompanying its formation was established.     

Synthesis and crystal structure of the complex [Nd(2-EOBA)<Subscript>3</Subscript>(phen)(H<Subscript>2</Subscript>O)]<Subscript>2</Subscript> · H<Subscript>2</Subscript>O

A novel lanthanide complex of [Nd(2-EOBA)₃(phen)(H₂O)]₂ · H₂O (2-EOBA = 2-ethoxylbenzoate, phen = 1,10-phenanthroline), has been synthesized and structurally characterized by single crystal X-ray diffraction. The complex crystallizes in monoclinic, space group P2(1)/n with a = 14.7453(18) Å, b = 12.3628(15) Å, c = 19.473(2) Å, α = 90°, β = 93.349(2)°, γ = 90°. Two Nd³⁺ ions are connected together by two bridging 2-EOBA ligands and each Nd³⁺ ion is further coordinated by two chelating 2-EOBA ligands, one chelating phen molecule and one water molecule. The coordination number of Nd³⁺ ion is nine. The coordination geometry of Nd³⁺ ion is a distorted monocapped square-antiprism.     

Synthesis,structure and magnetic properties of the pentanuclear complex [Fe<Subscript>2</Subscript>(CN)<Subscript>12</Subscript>Ni<Subscript>3</Subscript>(L)<Subscript>6</Subscript>]·27H<Subscript>2</Subscript>O,where L is nitronyl nitroxide

We succeeded in synthesizing a new high-spin complex [Fe₂(CN)₁₂Ni₃(L)₆]·27H₂O, where L is stable nitroxide 2-(imidazol-4-yl)-4,4,5,5-tetramethyl-2-imidazoline-3-oxide-1-oxyl. According to X-ray diffraction data, the metal core of the pentanuclear [Fe₂(CN)₁₂Ni₃(L)₆] molecule is a trigonal bipyramid with Fe atoms occupying the axial positions and linked via CN bridges to {NiL₂} fragments laying in the equatorial plane. A peculiarity of this coordination compound is a large number of water molecules per the [Fe₂(CN)₁₂Ni₃(L)₆] pentanuclear molecule in the structure. The complex character of the μ_eff(T) dependence points to many competing channels of exchange interactions between the three types of paramagnetic centers.     

Synthesis of finely disperse nickel particles by thermolysis of complex (N<Subscript>2</Subscript>H<Subscript>5</Subscript>)[Ni(NH<Subscript>2</Subscript>NHCOO)<Subscript>3</Subscript>] · H<Subscript>2</Subscript>O in organic liquids and refinement of crystal structure of this complex

The crystal structure of the complex (N₂H₅)[Ni(NH₂NHCOO)₃] · H₂O (I) was refined using X-ray diffraction data (obtained on an Apex X8 diffractometer, MoK _α radiation, 1830 F _hkl , R = 0.0182). The structure is built of complex anions [Ni(NH₂NHCOO)₃]⁻, cations N₂H₅⁺, and water molecules and is characterized by strong hydrogen bonds N-H…O, O-H…O, and N-H…N. The N₃O₃ coordination polyhedron around a Ni atom is a slightly distorted octahedron. The thermal decomposition of complex I was studied in high-boiling organic liquids. The feasibility of preparing non-pyrophoric nickel powders having particle sizes of up to 20 nm is shown.     

Magnetic properties of a linear trinuclear manganese compound [Mn<Subscript>3</Subscript>(PhCO<Subscript>2</Subscript>)<Subscript>6</Subscript>(Bipy)<Subscript>2</Subscript>] · H<Subscript>2</Subscript>O

The reaction of the trinuclear oxo-centered mixed-valence complex [Mn₃O(O₂CPh)₆(Py)₂(H₂O)] with 2,2′-bipyridyl (Bipy) and another potential tripodal ligand affords the title compound [Mn₃(PhCO₂)₆(Bipy)₂] · H₂O in good yield. The X-ray crystallographic diffraction study reveals that three mangenese ions are arranged in a linear mode with Mn_center-Mn_terminal and Mn_terminal-Mn_terminal diatances of 3.588 and 7.176 Å, respectively. Molar magnetic susceptibility of the compound gradually decreases from 12.23 (300 K) to 4.45 cm³ K mol^?1 (2 K). Taking into account the structure of this compound, the data in the 2.0–300 K range were fit to the appropriate theoretical expression to give J = ?2.73 cm^?1, ρ = 2.07%, N _a = ?0.0004 cm³ mol^?1, g = 1.992, and R ² = 0.99996. The magnetization versus external magnetic field measurements at 2 K shows that the ground state is S _T = 5/2.     

Non-isothermal kinetics of thermal decomposition of NH<Subscript>4</Subscript>ZrH(PO<Subscript>4</Subscript>)<Subscript>2</Subscript>·H<Subscript>2</Subscript>O

Nanocrystalline NH₄ZrH(PO₄)₂·H₂O was synthesized by solid-state reaction at low heat using ZrOCl₂·8H₂O and (NH₄)₂HPO₄ as raw materials. X-ray powder diffraction analysis showed that NH₄ZrH(PO₄)₂·H₂O was a layered compound with an interlayer distance of 1.148 nm. The thermal decomposition of NH₄ZrH(PO₄)₂·H₂O experienced four steps, which involves the dehydration of the crystal water molecule, deamination, intramolecular dehydration of the protonated phosphate groups, and the formation of orthorhombic ZrP₂O₇. In the DTA curve, the three endothermic peaks and an exothermic peak, respectively, corresponding to the first three steps' mass losses of NH₄ZrH(PO₄)₂·H₂O and crystallization of ZrP₂O₇ were observed. Based on Flynn–Wall–Ozawa equation and Kissinger equation, the average values of the activation energies associated with the NH₄ZrH(PO₄)₂·H₂O thermal decomposition and crystallization of ZrP₂O₇ were determined to be 56.720 ± 13.1, 106.55 ± 6.28, 129.25 ± 4.32, and 521.90 kJ mol⁻¹, respectively. Dehydration of the crystal water of NH₄ZrH(PO₄)₂·H₂O could be due to multi-step reaction mechanisms: deamination of NH₄ZrH(PO₄)₂ and intramolecular dehydration of the protonated phosphate groups from Zr(HPO₄)₂ are simple reaction mechanisms.     

Synthesis and crystal structure of [Cr(NH<Subscript>3</Subscript>)<Subscript>5</Subscript>Cl][PdCl<Subscript>4</Subscript>]·H<Subscript>2</Subscript>O

Synthesis and investigation of a binary complex salt [Cr(NH₃)₅Cl][PdCl₄]·H₂O is reported. The compound is isostructural with [Rh(NH₃)₅Cl][PdCl₄]·H₂O studied earlier; it was characterized by element analysis and powder and single crystal X-ray diffraction. Crystal data for H₁₇Cl₅N₅OPdCr: a = 7.8668(12) Å, b = 10.9703(16) Å, c = 16.048(2) Å, = 102.469(3)°, space group P2₁/c, Z = 4, V = 1352.3(3)ų, d _calc = 2.155 g/cm³.Original Russian Text Copyright © 2004 by I. A. Baidina, P. E. Plyusnin, S. V. Korenev, K. V. Yusenko, Yu. V. Shubin, and S. A. GromilovTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 3, pp. 549–552, May–June 2004.