Multifunctional iron thiocarboxylate complexes: synthesis,reactivity and structure of CpFe(CO)<Subscript>2</Subscript>SCO-3,5-C<Subscript>6</Subscript>H<Subscript>4</Subscript>(COCl)<Subscript>2</Subscript>

A controlled substitution reaction of the chlorine atoms of 1,3,5-benzenetricarbonyl trichloride by the organoiron fragment (CpFe(CO)₂S) has been achieved. The complexes CpFe(CO)₂SCO-3,5-C₆H₃(COCl)₂ (1), 1,3-[CpFe(CO)₂SCO]₂-5-C₆H₃COCl (2) and 1,3,5-[CpFe(CO)₂SCO]₃C₆H₃ (3) were prepared from the reaction of (μ-S _x )[CpFe(CO)₂]₂ (x = 3, 4) with 1,3,5-C₆H₃(COCl)₃ in a 1:1, 2:1, or 3:1 metal to ligand molar ratio. The reactions of (1) with amines, thiols, and carboxylic acids produce the trifunctional mono-iron complexes CpFe(CO)₂SCO-3,5-C₆H₃(COY)₂ [Y = NR₂ (4), SR (5), OCOR (4)]. The X-ray structure determination of (1) is reported.     

Determination of the primary structure and carboxyl p<Emphasis Type="Italic">K</Emphasis><Subscript>A</Subscript>s of heparin-derived oligosaccharides by band-selective homonuclear-decoupled two-dimensional <Superscript>1</Superscript>H NMR

Determination of the structure of heparin-derived oligosaccharides by ¹H NMR is challenging because resonances for all but the anomeric protons cover less than 2 ppm. By taking advantage of increased dispersion of resonances for the anomeric H¹ protons at low pD and the superior resolution of band-selective, homonuclear-decoupled (BASHD) two-dimensional ¹H NMR, the primary structure of the heparin-derived octasaccharide ∆UA(2S)-[(1 → 4)-GlcNS(6S)-(1 → 4)-IdoA(2S)-]₃-(1 → 4)-GlcNS(6S) has been determined, where ∆UA(2S) is 2-O-sulfated ∆^4,5-unsaturated uronic acid, GlcNS(6S) is 6-O-sulfated, N-sulfated β-d-glucosamine and IdoA(2S) is 2-O-sulfated α-l-iduronic acid. The spectrum was assigned, and the sites of N- and O-sulfation and the conformation of each uronic acid residue were established, with chemical shift data obtained from BASHD-TOCSY spectra, while the sequence of the monosaccharide residues in the octasaccharide was determined from inter-residue NOEs in BASHD-NOESY spectra. Acid dissociation constants were determined for each carboxylic acid group of the octasaccharide, as well as for related tetra- and hexasaccharides, from chemical shift–pD titration curves. Chemical shift–pD titration curves were obtained for each carboxylic acid group from sub-spectra taken from BASHD-TOCSY spectra that were measured as a function of pD. The pK _As of the carboxylic acid groups of the ∆UA(2S) residues are less than those of the IdoA(2S) residues, and the pK _As of the carboxylic acid groups of the IdoA(2S) residues for a given oligosaccharide are similar in magnitude. Relative acidities of the carboxylic acid groups of each oligosaccharide were calculated from chemical shift data by a pH-independent method.     

Reaction of Sulfur and Oxygen-Bridged 8-Quinolinolato Trinuclear Molybdenum Cluster [Mo<Subscript>3</Subscript>OS<Subscript>3</Subscript>(qn)<Subscript>3</Subscript>(H<Subscript>2</Subscript>O)<Subscript>3</Subscript>]<Superscript>+</Superscript> with Acetylene Carboxylic Acids

The reaction of a sulfur and oxygen-bridged 8-quinolinolato trinuclear molybdenum cluster [Mo₃OS₃(qn)₃(H₂O)₃]⁺ (3; Hqn = 8-quinolinol) with equimolar amounts of acetylene carboxylic acid, 4-pentynoic acid, 5-hexynoic acid, acetic acid, and pimelic acid gave clusters having μ-carboxylato groups, [Mo₃OS₃(qn)₃(H₂O)(μ-HC≡CCOO)] (6), [Mo₃OS₃(qn)₃(H₂O)(μ-HC≡C(CH₂)₂COO)] (7), [Mo₃OS₃(qn)₃(H₂O)(μ-HC≡C(CH₂)₃COO)] (8), [Mo₃OS₃(qn)₃(H₂O)(μ-CH₃COO)] (4), and [{Mo₃OS₃(qn)₃(C₂H₅OH)}₂(μ-C₇H₁₀O₄)] (5), respectively. X-ray structural analyses, ¹H NMR, and electronic spectra of these clusters made clear that each of the COO⁻ groups of the reagents bridges two Mo atoms in each cluster and that no adduct formation occurred at the sulfurs in the clusters. The reaction of 3 with a large excess-molar amount (50 times) of acetylene carboxylic acid gave [Mo₃OS(μ₃-SCH=C(COOH)S)(qn)₃(H₂O)(μ-HC≡CCOO)] (9) with two molecules of acetylene carboxylic acid, one acting as a carboxylato bridge and the other in adduct formation, as supported by the electronic and ¹H NMR spectra. The corresponding aqua cluster [Mo₃OS₃(H₂O)₉]⁴⁺ (1), on the contrary, reacts with acetylene carboxylic acid to give adduct [Mo₃OS(μ₃-SCH=C(COOH)S)(H₂O)₉]⁴⁺ (2). Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Amine exchange reactions of 3-<Emphasis Type="Italic">tert</Emphasis>-butyl-6-(methylsulfanyl)-1,2,3,4-tetrahydro-1,3,5-triazine hydroiodide with amino acids

3-tert-Butyl-6-(methylsulfanyl)-1,2,3,4-tetrahydro-1,3,5-triazine hydroiodide enters into the amine exchange reaction with glycine and β-alanine in aqueous solution. The final exchange products are [4-(methylsulfanyl)-5,6-dihydro-1,3,5-triazin-3-ium-1(2H)-yl] acetate and 3-[4-(methylsulfanyl)-5, 6-dihydro-1,3,5-triazin-3-ium-1(2H)-yl] propanoate, respectively, crystallizing together with t-butylamine hydroiodide from aqueous or aqueous alcoholic solutions as ion associates, which also can be detected in solution in DMSO-d ₆. [4-(Methylsulfanyl)-5,6-dihydro-1,3,5-triazin-3-ium-1(2H)-yl] acetate can be extracted directly from the reaction mixture after carrying out the amine exchange in aqueous isopropanol or 95% ethanol, as well as by “recrystallization“ of its associate with tert-butylamine hydroiodide from aqueous isopropanol.     

Cyclothiomethylation of heterochain α,ω-diamines with formaldehyde and H<Subscript>2</Subscript>S

Cyclothiomethylation was performed of heterochain (O, S-S, NH) α,ω-diamines with formaldehyde and H₂S in aqueous medium at 20–60°C to obtain new α,ω-bis(1,3,5-dithiazinanes). The cyclocondensation of N-(3-aminopropyl)butane-1,4-diamine (spermidine), formaldehyde, and H₂S proceeds efficiently in the medium of BuOH-H₂O at 0°C and leads to the formation of previously unknown O,S-containing macroheterocycle, 1,7-dioxa-3,5,9,11-tetrathiacyclododecane. A fungicidal activity was found in 5,5′-(3,6-dioxaoctane-1,8-diyl)bis-1,3,5-dithiazinane with respect to microscopic fungi affecting agriculture.     

Cyclothiomethylation of aryl hydrazines with formaldehyde and hydrogen sulfide

Cyclothiomethylation of phenyl hydrazine with CH₂O and H₂S in a ratio of 1: 3: 2 in an acidic medium (HCl) afforded previously unknown 3-phenyl-1,3,4-thiadiazolidine (35% yield) and N-phenyl(perhydro-1,3,5-dithiazin-5-yl)amine (35% yield). The analogous reaction in an alkaline medium (BuONa) produced N-phenyl(perhydro-1,3-thiazetidin-3-yl)amine (22% yield). The reaction of 1,2-diphenyl hydrazine with CH₂O and H₂S in an alkaline medium gave 1,2,4,5-tetraphenylhexahydro-1,2,4,5-tetrazine and previously unknown 3,4-diphenyl-1,3,4-thiadiazolidine and 5,6-diphenyltetrahydro-1,3,5,6-dithiadiazepine in 39 and 22% yields, respectively. Cyclothiomethylation of benzyl hydrazine afforded previously unknown bis[(6-benzyl-4,2,6-thiadiazolidin-2-yl)methyl] sulfide (60% yield) and N-benzyl(perhydro-1,3,5-dithiazin-5-yl)amine (19% yield). The reaction of tosyl hydrazine produced 3-[(p-tolyl)sulfonyl]-1,3,4-thiadiazolidine, N-(perhydro-1,3,5-dithiazin-5-yl)-p-tolylsulfonamide, and 3,7-bis(p-tolylsulfonylamino)-1,5-dithia-3,7-diazacyclooctane in 21, 38, and 41% yields, respectively. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1758–1767, October, 2006.     

Heterocyclization of hydrazine with acetaldehyde and H2S

Hydrazine is regioselectively condensed with a mixture of acetaldehyde and H₂S at a temperature below −10 °C to form 2,4,6,8-tetramethyl-3,7-dithia-1,5-diazabicyclo[3.3.0]-octane. The reaction at 0 °C with the reverse order of mixing of the starting reagents affords 2,4,6-trimethyl(1,3,5-dithiazinan-5-yl)amine as the major product.     

Transformations of Perfluorinated 2-Alkyl- and 2,2-Dialkylbenzocyclobutenones in SbF<Subscript>5</Subscript> and SiO<Subscript>2</Subscript>-SbF<Subscript>5</Subscript>

Perfluorinated 2-methyl- and 2-ethylbenzocyclobutenones on heating in SbF₅ underwent isomerization into perfluoroindan-1-one and perfluoro(2-methylindan-1-one), while their reaction with SiO₂—SbF₅ gave perfluorinated 3-methyl- and 3-ethylphthalides, respectively. Perfluorinated 2-ethyl-2-methyl- and 2,2-diethylbenzocyclobutenones reacted with SbF₅ to produce perfluorinated 2-(but-2-en-2-yl)- and 2-(pent-2-en-3-yl)-benzoic acids, and their transformations in SbF₅ over SiO₂ afforded 5,6,7,8-tetrafluoro-1-oxo-3-trifluoromethyl-1H-isochromene-4-carboxylic acid and perfluoro(4-ethyl-3-methyl-1H-isochromen-1-one), respectively.     

Low-temperature catalytic preparation of multi-wall MoS<Subscript>2</Subscript> nanotubes

In the catalytic reduction atmosphere of H₂+CH₄+C₄H₄S, the ball-milled precursor (NH₄)₂MoS₄ is heated to 300°C for decomposition. The as-synthesized product is characterized by XRD, SEM, HRTEM, EDX, and BET. The results show that multi-wall MoS₂ nanotubes are obtained. The length of the nanotubes is around 3–5 μm. The diameters of the nanotubes are homogeneous, with an inner diameter of ∼15 nm, an outer diameter of ∼30 nm, and an interlayer (002) d-spacing of 0.63 nm. This catalytic thermal reaction occurring at low temperatures is important for the large-scale preparation of similar transition-metal disulfide nanotubes.     

Electrical conductivity studies in the system Li<Subscript>2</Subscript>TiO<Subscript>3</Subscript>-Li<Subscript>1.33</Subscript>Ti<Subscript>1.67</Subscript>O<Subscript>4</Subscript>

Electrical conductivity in the monoclinic Li₂TiO₃, cubic Li_1.33Ti_1.67O₄, and in their mixture has been studied by impedance spectroscopy in the temperature range 20–730 °C. Li₂TiO₃ shows low lithium ion conductivity, σ₃₀₀≈10^–6 S/cm at 300 °C, whereas Li_1.33Ti_1.67O₄ has 3×10^–8 at 20 °C and 3×10^–4 S/cm at 300 °C. Structural properties are used to discuss the observed conductivity features. The conductivity dependences on temperature in the coordinates of 1000/T versus log_e(σT) are not linear, as the conductivity mechanism changes. Extrinsic and intrinsic conductivity regions are observed. The change in the conductivity mechanism in Li₂TiO₃ at around 500–600 °C is observed and considered as an effect of the first-order phase transition, not reported before. Formation of solid solutions of Li_{2– x} Ti_{1+ x} O₃ above 900 °C significantly increases the conductivity. Irradiation by high-energy (5 MeV) electrons causes defects and the conductivity in Li₂TiO₃ increases exponentially. A dose of 144 MGy yields an increase in conductivity of about 100 times at room temperature. Electronic Publication     

Synthesis,structure, and magnetic properties of the cobalt(<Emphasis Type="SmallCaps">II</Emphasis>) 1,3,5-benzenetricarboxylate layered coordination polymer

The reaction of Co(NO₃)₂·6H₂O with 1,3,5-benzenetricarboxylic acid (H₃btc, trimesic acid) in DMF at 100 °C afforded the coordination polymer [Co₃(dmf)₆(btc)(Hbtc)(H₂btc)]··9H₂O (1) (dmf is N,N′-dimethylformamide, DMF). According to the X-ray diffraction study, the metal-organic coordination polymer is composed of planar honeycomb (6,3) networks, in which the organic benzenetricarboxylate anions and the inorganic Co²⁺ cations play a role of three-connected nodes. Disordered water molecules are intercalated between the layers. A study of the magnetic properties showed the presence of a weak antiferromagnetic coupling between the Co²⁺ ions (S = 3/2). Dedicated to Academician G. A. Abakumov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1719–1723, September, 2007.     

Effect of the production temperature on the structure of Si<Subscript>3</Subscript>N<Subscript>4</Subscript> nanofibers

The effect of the production temperature on the morphology and structure of Si₃N₄ nanofibers was investigated. It was shown that nanofibers produced in the temperature range of 1340–1360°C are amorphous while those produced at 1380°C and above are monocrystalline. Apart from the principal phase (α-Si₃N₄) the imide Si₂N₂NH was also found in the reaction products.     

Novel large heteropolymetalate complexes formed from Ni(II) and cryptate [As<Subscript>4</Subscript>W<Subscript>40</Subscript>O<Subscript>140</Subscript><Superscript>28-</Superscript>

The heteropolytungstate (NH4)₂₀[Na2(H₂O)₂Ni(H₂O)₅{Ni(H₂O)}₂As₄W₄₀O₁₄₀] · 61H₂O is obtained by the reaction of Na₂₇[NaAs₄W₄₀O₁₄₀] · 60H₂O with NiCl₂ · 6H₂O and NH₄Cl in pH≈4.0. The structure and chemical composition are determined by X-ray diffraction analysis and element analysis. The crystal data and main structure refinement are: a = 1.33135(18) nm, b = 1.9722(3) nm, c = 3.6430(5) nm, α = 78.010(2)°, β = 82.145(2)δ, γ = 74.385(2)°, V = 8.978(2) nm³, triclinic crystal system, space group: P1, Z = 2, R1 = 0.0512, and wR2 = 0.0684(I >2σ). The four S2 sites of the big cyclic ligand [As₄W₄₀O₁₄₀]^28- are occupied by two Na⁺ and two Ni²⁺ respectively, and each site supplies four O_d coordinating to metal ion. The coordination number of Ni²⁺ is six, and that of two Na⁺ is five and six respectively. The third Ni²⁺ locates outside the cyclic [As₄W₄₀O₁₄₀]^28- and connects with one O_d, and its coordination number is six.     

Preparation,Thermal Behaviour,and Crystal Structure of MgAl<Subscript>2</Subscript>F<Subscript>8</Subscript>(H<Subscript>2</Subscript>O)<Subscript>2</Subscript>

Summary.  Single crystals of MgAl₂F₈(H₂O)₂ have been obtained under hydrothermal conditions (250°C, 14 d) from a starting mixture of AlF₃ and MgAlF₅(H₂O)₂ in a 5% (w/w) HF solution. The crystal structure has been determined and refined from single crystal data (Fmmm (#69), Z = 4, a = 7.2691(7), b = 7.0954(16), c = 12.452(2) ?, 281 structure factors, 27 parameters, R(F ² > 2σ (F ²)) = 0.0282, wR(F ² all) = 0.0885). The obtained crystals were systematically twinned according to (010/100/001) as twinning matrix, reflecting the pseudo-tetragonal metric. The crystal structure is composed of perowskite-type layers built of corner sharing AlF₆ octahedra with an overall composition of AlF₄ ⁻ which are connected via common fluorine atoms of [MgF_4/2(H₂O)_2/1] octahedra. Group-subgroup relations of MgAl₂F₈(H₂O)₂ to WO₃(H₂O)_0.33 and to other M(II)M(III)₂ F₈(H₂O)₂ structures are briefly discussed. Above 570°C, MgAl₂F₈(H₂O)₂ decomposes under elimination of water into α-AlF₃, β-AlF₃, and MgF₂. Received October 29, 2001. Accepted (revised) December 6, 2001     

The microstructure and magnetic properties of Ni<Subscript>0.4</Subscript>Zn<Subscript>0.6</Subscript>Fe<Subscript>2</Subscript>O<Subscript>4</Subscript> films prepared by spin-coating method

Nickel zinc ferrite (Ni_0.4Zn_0.6Fe₂O₄) films on Si (100) substrate were synthesized using a spin-coating method. The crystallinity of the Ni_0.4Zn_0.6Fe₂O₄ films with the thickness of about 386 nm became better as the annealing temperature increased. The films have smooth surface, relatively good packing density and uniform thickness. The volatilization of Zn is serious at 900 °C. With the increase of annealing temperature, the saturation magnetization M _s increases in the temperature ranging from 400 to 700 °C, however, decreases above 700 °C, and the coercivity H _c increases in the temperature range 400–800 °C, decreases above 800 °C. After annealed at 700 °C for 2 h in air with the heating rate 2 °C/min, the film shows a maximum saturation magnetization M _s of 349 emu/cc and low coercivity H _c of 66 Oe. The M _s is higher than others which prepared by this method, however, the H _c is lower. The M _s of Ni_0.4Zn_0.6Fe₂O₄ films annealed at 700 °C increases with increasing annealing time and the H _c changes slightly.     

Synthesis,crystal structure,and <Superscript>1</Superscript>H NMR spectra of a chloride-bridged chain complex of dinuclear ruthenium(II,III) 3,4,5-tri(ethoxy-<Emphasis Type="Italic">d</Emphasis><Subscript>5</Subscript>)benzoate

Deuterated dinuclear ruthenium(II,III) 3,4,5-tri(ethoxy-d ₅)benzoate, [Ru₂{3,4,5-(C₂D₅O)₃C₆H₂-COO}₄Cl] _n , was synthesized by a reaction of [Ru₂(C₂H₅COO)₄Cl] _n and 3,4,5-tri(ethoxy-d ₅)benzoic acid and characterized by single-crystal X-ray analysis as well as IR, UV-VIS, and ¹H NMR spectra, and compared with those of the undeuterated complex [Ru₂{3,4,5-(C₂H₅O)₃C₆H₂COO}₄Cl] _n . Single-crystal X-ray analysis showed that chloride ligands bridge the dinuclear ruthenium(II,III) units at the axial positions to form a zigzag chain molecule with the Ru¹-Cl-Ru² angle of 123.82(4)°. ¹H NMR spectra in CD₂Cl₂ displayed a broad signal attributable to o-H atoms on the phenyl rings of the benzoate ligands from approximately δ = 23 to δ = 32 at 25°C and several signals from approximately δ = −50 to δ = 50 at −80°C. These spectra show the preservation of the polymeric or oligomeric chain structure in dichloromethane, which is supported by the solution behavior confirmed by the UV-VIS spectra and electronic conductance.     

Influence of solvent structure on the aquation of <Emphasis Type="BoldItalic">trans</Emphasis>-[Ru(3-MePy)<Subscript>4</Subscript>Cl<Subscript>2</Subscript>] complex in mixed aqueous solvents

The kinetics of the solvolytic aquation of trans-[Ru (3-Me Py)₄Cl₂] was studied spectrophotometrically in water – isopropanol in the range (30–90% v/v), and water acetonitrile in the range (10–70% v/v), and in the temperature range 50–65 °C. Plots of log k versus the reciprocal of the relative permittivity and Grunwald–Winstien gave non-linear plots. This non-linearity is derived from a large differential effect of solvent structure between the initial and transition states. The plot of log k versus water concentration was also non linear; evidence for the presence of a S _N ¹ mechanism. However, extrema in the variation of enthalpy ΔH* and entropy ΔS* of activation correlate well with the extrema in physical properties of the mixtures which are related to changes in solvent structure. Linear plots of ΔH* versus ΔS* were obtained and the iso- kinetic temperature indicates that the reaction is entropy controlled.     

The synthesis and selected properties of Co<Subscript>2</Subscript>InV<Subscript>3</Subscript>O<Subscript>11</Subscript>

It has been demonstrated that Co₂V₂O₇ and InVO₄ react with each other forming a new compound of the Co₂InV₃O₁₁ formula, when their molar ratio is equal to 1:1, or among CoCO₃, In₂O₃ and V₂O₅, mixed at a molar ratio of 4:1:3. This compound melts incongruently at the temperature of 960±5°C, depositing crystals of InVO₄. It crystallizes in the triclinic system and the unit cell parameters amount to: a=0.6524(6) nm, b=0.6885(5) nm, c=1.0290(4) nm, α=96.5°, β=104.1°, γ=100.9°, Z=2. The phase equilibria being established in the Co₂V₂O₇–InVO₄ system over the whole components concentration range up to the solidus line were described.     

XAFS investigation of [Pd(NH<Subscript>3</Subscript>)<Subscript>4</Subscript>][AuCl<Subscript>4</Subscript>]<Subscript>2</Subscript> and its thermolysis products

Thermolysis of double complex salt [Pd(NH₃)₄][AuCl₄]₂ has been studied in helium atmosphere from ambient to 350 °C. The XAFS of Pd K and Au L₃ edges and thermogravimetry measurements have been carried out to characterize the intermediates and the final product. In the temperature range 115–160 °C the complex is decomposed to form Pd(NH₃)₂Cl₂ and AuCl_4−x N _x species with x ranging from 2 to 3. Subsequent heating of the intermediate up to 300 °C leads to the total loss of NH₃. The Au–Cl and Au–Au bonds form the local environment of Au at the stage of decomposition while only four chlorine atoms are around Pd. At the temperature of 330 °C the Au and Pd nanoparticles as well as residues of palladium chloride are detected. The final product consists of separated Au and Pd nanoparticles.     

Synthesis of azoles from 3,3′-[(4-alkoxyphenyl)imino]bis(propanoic acid hydrazides)

Abstract  

Reaction of 3,3′-[(4-alkoxyphenyl)imino]bis(propanoic acid hydrazides) with CS₂ in alkaline solution and subsequent acidification gave 5,5′-[[(4-alkoxyphenyl)imino]diethane-2,1-diyl]bis(1,3,4-oxadiazole-2(3H)-thiones). The same dihydrazides on reaction with phenyl isocyanates or phenyl isothiocyanates were converted to bis[N′-(phenylaminocarbonyl)propanoic acid hydrazides] and bis[N′-(phenylaminocarbonothioyl)propanoic acid hydrazides], which underwent cyclization in alkaline medium to produce 5,5′-[[(4-alkoxyphenyl)imino]diethane-2,1-diyl]bis(4-phenyl-2,4-dihydro-3H-1,2,4-triazol-3-ones) and their 3-thio analogues, whereas in sulfuric acid or POCl₃ 5,5′-[[(4-alkoxyphenyl)imino]diethane-2,1-diyl]bis(N-phenyl-1,3,4-oxadiazol-2-amines) and 5,5′-[[(4-alkoxyphenyl)imino]diethane-2,1-diyl]bis(N-phenyl-1,3,4-thiadiazol-2-amines) were obtained.