Mobility of the dppm ligand in dinuclear RuRh complexes: formation of trinuclear RuRh2 and RuRhCu derivatives,and X-ray structure of a new heterobimetallic hydrido-bridged complex

Protonation of RuRhH₂Cl(COD)(dppm)₂ (1) (COD = 1,5 cyclooctadiene, dppm = bisdiphenylphosphinomethane) with HBF₄ · Et₂O gives [RuRhHCl(COD)-(dppm)₂]BF₄ (2), which has been shown to contain two chelating dppm ligands on ruthenium and a bridging hydride (RuH 2.08(7) Å; RhH 1.64(8) Å). Complex 2 reacts with CO to give [RuRhHCl(CO)₃(dppm)₂]BF₄ (3) containing two bridging dppm groups. Reaction of 1 with 0.5 molar equivalents of [RhCl(COD)]₂ at 80°C affords the trinuclear RuRh₂H₂Cl(PhPCH₂PPh₂)(COD)₂(dppm) (4) in low yield (25%), and that with CuCl at room temperature gives RuRhCuH₂Cl₂ (COD)(dppm)₂ (5) in high yield. Complex 5 is not very stable in solution and is converted into RuCuH₂Cl(dppm)₂ (6), a typical adduct between a Lewis acid and a hydride complex, which can be more easily obtained from RuH₂(dppm)₂ and CuCl in toluene at 80°C.     

Hydrothermal synthesis and structure determination of Ag3(VVO2){O3PCH2PO3} or MIL-42: a new vanadium(V) methylendiphosphonate inserting silver cations

A new formulated compound, Ag₃(V^VO₂){O₃PCH₂PO₃} or MIL-42, was synthesized hydrothermally at 170 °C. It crystallizes in the monoclinic system (space group P2₁/n (n°14)) with lattice parameters a=8.9404(2) Å, b=8.0226(2) Å, c=11.7395(1) Å and β=100.720(1)°, V=827.32(3) ų, Z=4. Its structure was determined from single crystal X-ray diffraction data (R₁(F_o)=0.0231, wR₂(F_o²)=0.0588 for 2126 unique reflections with I≥2σ(I)). MIL-42 is three-dimensional with one-dimensional chains of corner linked trimeric units related by sheets of Ag⁺ in tetrahedral and five-fold coordination. The chains are built up from V^VO₅ trigonal bipyramids; one edge of their equatorial plane is chelated by one methylendiphosphonate group. The silver sheets are built up from corner-sharing hexamers in which silver exhibits tetrahedral and five-fold coordination.     

Glass-forming region and structure in SiS2Li2SLiX (X = Br,I)

The glass-forming region in the SiS₂Li₂SLiX (X = Br, I) system, as determined by X-ray diffraction, has been extended to higher lithium content by the use of a direct liquid nitrogen quench. The base glass, 0.4SiS₂0.6Li₂S, was synthesized and doping up to 0.28SiS₂0.42Li₂S0.30LiBr and 0.24SiS₂0.36Li₂S0.40LiI was achieved. The properties of these glasses are compared to the glasses formed by previously reported quenching methods.Vibrational assignments have been made from infrared investigation of the glasses using FT-IR. The basic glass network consists of SiS₄ tetrahedra while the addition of Li₂S as a network modifier produced nonbridging sulfur. Doping with lithium halide did not significantly change the glass network, i.e., no changes in IR peak positions were observed. However, the higher lithium ion concentration resulted in higher mobility and ionic conduction.     

Synthesis and structure of a new polyoxometalate-based inorganic–organic hybrid and application as a chemically bulk-modified electrode

A new Keggin-type polyoxometalate-based inorganic–organic hybrid, [Cu(H₂O)₂(daphen)]₂[SiW₁₂O₄₀]·9H₂O (1) (daphen?=?5,6-diamino-1,10-phenanthroline), was hydrothermally synthesized, and characterized by single-crystal X-ray diffraction, elemental analysis, infrared spectroscopy, fluorescence spectra, and thermal analysis. Single-crystal X-ray diffraction analysis reveals that in 1, [SiW₁₂O₄₀]^4? is a tetradentate ligand with its four terminal oxygens coordinating to four Cu(II)–daphen fragments to form a 2D sheet with (4,4) topology. On the basis of the insolubility of 1 in water and common organic solvent and its reversible multielectron redox processes, 1 was used to fabricate a bulk-modified carbon paste electrode (1-CPE) by direct mixing. Electrochemistry indicated that 1-CPE is stable over hundreds of cycles and possessed electrocatalytic activity toward the reduction reactions of nitrite.     

Synthesis and selected properties of a new solid solution in the Zn2FeV3O11–Mg2FeV3O11 system

The binary Zn₂FeV₃O₁₁?CMg₂FeV₃O₁₁ system has been studied by XRD, DTA, IR, and SEM methods. A new continuous substitution solid solution with the formula Zn_2?x Mg _x FeV₃O₁₁ has been obtained by high-temperature synthesis. The DTA investigations were used to choose the heating temperatures as well as for determination of thermal stability of the new triclinic phase. The influence of the degree of Mg²⁺ ion incorporation on the unit cell volume as well as on the position of the IR absorption bands of the solid solution have been determined. The morphology of crystals of the new phase is presented.     

Synthesis of a new macrocyclic compound and its self-assembly

A new macrocyclic compound has been synthesized by condensation of pyridine-1-oxide-2,6-dialdehyde with diethylenetria-mine. The self-assemly behaviours were studied by X-ray diffraction. The results show that the self-assembly were controlled by intermolecular hydrogen bonds and π-π stacking effects.     

Experimental indication of a new spectator effect in Na+CO2 collisions

Na⁺CO₂ differential scattering experiments at ion energies between 50 and 350 eV are reported. The measured energy-loss distribution show a pattern that is typical for spectra which could be interpreted in terms of an impulsive collision process. The structure can partly be explained as rotational rainbow peaks caused by the interaction of the Na⁺ ion with only the CO part of the CO₂ molecule.     

Synthesis and crystal structure of a new paramagnetic complex salt of diprotonated dioxocyclam with PtCl 2− 4 and water (1:1:1)

The paramagnetic complex salt of diprotonated dioxocyclam (1,11-dihydro-5,7-dioxo-1,4,8,11tetra-azacyclotetradecane), Pt(II) tetrachloride and water has been synthesized in strongly acidic medium and identified by X-ray structure analysis. The crystals of [(C₁₀H₂₂N₄O₂)²⁺(PtCl₄)^2–]·H₂O are monoclinic, space groupP2₁ c,M _r=585.23,a=9.516(1) Å,b=11.926(1) Å,c=16.622(2) Å,=102.88(2)°,V=1839(1)ų,Z=4,D _x=2.114 g cm^–3, (MoK )=0.70930 Å,=83.1 cm^–1,F(000)=1128,T=292 K,R=0.019 for 2808 observed reflections withI > 3(I). Alternating moieties of diprotonated dioxocyclam and a PtCl _2– ⁴ anion form columns running down the c axis. Water molecules are localized in the intercolumnar space and contribute to the extensive hydrogen bond network. The macrocycle conformation is characterized by two sequences of torsional angles, corresponding to two different subunits. The shorter sequence idealized as (-sc, ap, -ac, + ac, ap, +sc) [sc( ±60°), ac( ±120°), ap(180°)], describing the C pseudosymmetric part of the molecule, is centered on a -CH₂ group between the two peptide O-C-N-H fragments. The opposite C pseudosymmetric subunit has a nearly (-sc, ac, -SC, ap)₂ conformation. Pt is square planar coordinated by four Cl atoms, Pt-Cl_ve = 2.306(8) Å. The shortest Pt ... Pt distance is 7.200(1) Å.     

Reinvestigation of phase relations in the CaOUO2 system

Phase relationships in the binary CaOUO₂ system were reinvestigated. In a carefully controlled reducing atmosphere the formation of binary compounds was not detected and only extensive solid solubility of CaO in UO₂ was observed. In controlled atmosphere in wet hydrogen, a perovskite, Ca₂ (Ca_0.67U⁴⁺_0.33)U⁵⁺O_5.83 is formed as the single binary Ca compound containing uranium in a 4+ valence state.     

Synthesis and structure of new β-functionalized gem-bromonitroethenes — 2-arylsulfanyl- and 2-aryloxy-3-bromo-3-nitroacrylates

Alkyl 2,3-dibromo-3-nitroacrylates react with arylthiols and phenols to give earlier unknown representatives of β-functionalized gem-bromonitroethenes, namely, 2-arylsulfanyl- and 2-aryloxy-3-bromo-3-nitroacrylates; their structure was characterized by IR, UV, and NMR (¹H, ¹³C{¹H}, HMQC, HMBC) spectroscopy. X-ray diffraction analysis showed that methyl 3-bromo-2-(4-chlorophenylsulfanyl)-3-nitroacrylate has a Z-configuration; the sulfanylbromonitrovinyl fragment in its molecule is relatively coplanar, while the ester group is almost perpendicular to the plane of the C-C double bond.

     

The extraction and determination of free lithium in LiB alloys

Extraction of the lithium phase from lithium-rich LiB alloys was achieved by reaction of the alloy with dry naphthalene dissolved in anhydrous tetrahydrofuran. The resulting radical anion was hydrolyzed and the lithium was determined by potentiometric titration from the moles of hydroxide formed. The composition of the Li_xB_y residue was determined by difference.     

Synthesis and crystal structure of a 2nm long rectangular copper dimetallomacrocycle §

A new mixed-heterocycle ‘extended-reach’ ligand has been synthesized and used to prepare copper(II) and nickel(II) complexes. An X-ray crystal structure determination reveals that the copper complex is an M₂L₂ metallomacrocycle having an unusual rectangular shape with a length of over 2nm stabilized by intramolecular π-stacking.     

Synthesis and x-ray crystal structure of a stable α-chlorooxetane

The Barton modification of the Hunsdiecker reaction is the key step in the preparation of 3,5-anhydro-5R-chloro-1,2-O-isopropylidenexylofuranose (1), a stable α-chlorooxetane.     

Synthesis and structure of a new compound (NH4)3[{Ta2(NH)3Cl6}Cl], with a novel imido-bridged chain: 1∞[Ta2(NH)3Cl6]2−

A new imido-bridged tantalum compound, (NH₄)₃[{Ta₂(NH)₃Cl₆}Cl], was synthesized from the mixture of TaCl₅, NaNH₂ and NH₄Cl (excess) in a vacuum sealed silica tube at 350–400 °C. Single crystal X-ray diffraction results for the title compound detailed in the orthorhombic space group Cmcm (No. 63); Z=4, a=10.1601(6) Å; b=19.8834(13) Å; and c=7.4362(4) Å. The structure consists of imido-bridged one-dimensional chains with composition [Ta₂(NH)₃Cl₆]²⁻ and running along c. These chains are separated by ammonium and chloride ions. In the present study, NH₄Cl was used to facilitate relatively smooth reaction between TaCl₅ and NaNH₂, which otherwise leads to an exothermic, self-propagating reaction.     

Synthesis and biological evaluation of potential new inhibitors of the bacterial transferase MraY with a β-ketophosphonate structure

Stable analogs of bacterial transferase MraY substrate or product with a pyrophosphate surrogate in their structure are described. β-ketophosphonates were designed as pyrophosphate bioisosteres and were investigated as UDP-GlcNAc mimics. The developed strategy allows introduction of structural diversity at a late stage of the synthesis. The biological activity of the synthesized compounds was evaluated on the MraY enzyme.     

Synthesis of a new bismuth oxide fluoride with the γ-Bi2O3 structure type

A new bismuth compound with the γ-Bi₂O₃ structure type has been synthesized by a hydrothermal method. The experimental results show that only the solution or starting materials which contain fluorine ions are effectual for the synthesis of the compound. Chemical analysis proved that the new compound contains a small amount of fluorine. We comment the stabilization of the γ-form by partial replacement of oxygen atoms with fluorine atoms and assume Bi₂₆O₃₈F₂ as its constitution. The measured dimension of the unit cell is 10.183(2) Å. Its thermal stability is also studied by differential thermal analysis.     

Synthesis of a new class of β-iodo N-alkenyl 2-pyridones

A new method for the synthesis of β-iodo N-alkenyl 2-pyridones from substituted 2-propargyloxypyridines has been discovered . These compounds present a unique complement of orthogonal functionality and structural characteristics that are unavailable via other routes. The ready access to these compounds renders them an important entry point for the preparation of more complex N-alkyl pyridone-containing targets.