Solubility of Copper(II) Chloride in Mixed Organic Oxygen-Containing Solvents

Solubility of copper(II) chloride at 25°C in binary organic solvents consisting of dimethyl sulfoxide, N,N-dimethylacetamide, and 1,4-dioxane was determined by the isothermal saturation method. The shape of solubility isotherms for all ternary systems under study is connected with the structural type of formed copper chloride solvates, the composition of which is defined by the solvent donor number. Solvates crystallize predominantly, where the metal ion coordinates molecules of the solvent with a greater donor power. The temperature increase in the system CuCl2–dimethylacetamide–dioxane up to 50°C leads to the formation of the cluster compound [Cu₄Cl₆O(DMA)₄]; its structure was determined by the X-ray structural analysis method.     

Photolysis of adamantane-2-spiru-3′-diazirine

The spectral characteristics and photochemical transformations of adamantane-2-spiro-3-diazirine and its 5-hydroxy derivative were studied. The transformations of the photoexcited molecules of adamantane-2-spiro-3-diazirine in individual solvents and their mixtures and with various sources of UV radiation were studied by gas-liquid chromatography. The main process in saturated hydrocarbons is the formation of diazoadamantane, which is then converted into adamantanone azine. The addition of small amounts of formic or acetic acid leads to the formation of significant amounts of alkyladamantanes, which are the products from transformations of the intermediately formed carbene adamantylidene. Concurrent transformation paths are also observed in cyclohexene. It is suggested that the adamantylidene is preceded by the formation of an exciplex of diazirine with the polar solvent molecule. The ambiphilic nature of adamantylidene in the photolysis of diazirines was demonstrated by concurrent carbenylation.Kiev Polytechnical Institute, L. V. Pisarzhevskii Institute of Physical Chemistry, Academy of Sciences of the Ukrainian SSR, Kiev. Higher Chemical Technology School, Prague. Translated from Teoreticheskaya i Ésperimental'naya Khimiya, Vol. 27, No. 2, pp. 211–220, March–April, 1991. Original article submitted July 11, 1989.     

Effect of competitive acido complex formation of the solubility of binary chlorides in MCl<Subscript>2</Subscript>-M′Cl<Subscript>2</Subscript>-H<Subscript>2</Subscript>O systems

The solubility of d-metal halides in MCl₂-M′Cl₂-H₂O systems with competitive complex formation at 25°C was discussed. The role of complex formation and hydration was traced. As the stability constants become closer to each other, the salting-in regions in the crystallization braches of both chlorides disappear. Original Russian Text I.V. Zamyatin, M.Yu. Skripkin, 2007, published in Zhurnal Obshchei Khimii, 2007, Vol. 77, No. 2, pp. 252–259.     

Influence of acido ligands on the structure of copper dihalide solvates with dimethyl sulfoxide and <Emphasis Type=Italic>N,N</Emphasis>-dimethylformamide

Structures of copper dihalide solvates with dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF) were determined by XRD single crystal analysis. The existence of two DMSO solvates with CuBr₂, but only one with CuCl₂, was attributed to a lower Cu-Br bond strength in comparison with Cu-Cl, and, as a consequence, by its easier breaking to form a bond with a solvent molecule. Fundamentally different structures of CuX₂·2DMF (X = Br, Cl) solvates are caused by different donor power of the acido ligands.     

The structure and formation of niobocene carbonyl heteronuclear derivatives. The molecular structures of Cp2Nb(CO)(μ-CO)Mn(CO)4, Cp2Nb(CO)(μ-H)Ni(CO)3 and [Cp2Nb(CO)(μ-H)]2Mo(CO)4

The heteronuclear Cp₂Nb(CO)(μ-CO)Mn(CO)₄ (I), Cp₂Nb(CO)(μ-H)Ni(CO)₃ (II) and [Cp₂Nb(CO)(μ-H)]₂M(CO)₄ (III, M = Mo;IV, M = W) complexes were prepared by reaction of Cp₂NbBH₄/Et₃N with Mn₂(CO)₁₀ in refluxing toluene, direct reaction of Cp₂NbBH₄ with Ni(CO)₄ in ether, and reaction of Cp₂NbBH₄/Et₃N with M(CO)₅. THF complexes (M = Mo or W) in THF/benzene mixture. An X-ray investigation of compounds I–III was performed. It is established that in I the bonding between Mn(CO)₅ and Cp₂Nb(CO) (with the angle (α) between the ring planes being 44.2(5)°) fragments takes place via a direct NbMn bond (3.176(1) Å) and a highly asymmetric carbonyl bridge (MnC_co 1.837(5) Å, NbC_co 2.781(5) Å). On the other hand, in complex II the sandwich Cp₂Nb(CO)H molecule (angle α = 37.8°) is combined with the Ni(CO)₃ group generally via a hydride bridge (NbH 1.83 Å, NiH 1.68 Å, NbHNi angle 132.7°) whereas the large Nb?Ni distance, 3.218(1) Å, shows the weakening or even absence of the direct NbNi bond. Similarly, in complex III two Cp₂Nb(CO)H molecules (with α angles equal to 41.4 and 43.0°, respectively) are joined to the Mo(CO)₄ group via the hydride bridges (NbH 1.83 and 1.75 Å and MoH 2.04 and 2.06 Å) producing a cis-form. The direct NbMo bonds are probably absent, since the Nb?Mo distances are rather long (3.579 and 3.565 Å). The effect of electronic and steric factors on the structure of heteronuclear niobocene carbonyl derivatives is discussed.     

Solubility of <Emphasis Type=Italic>d</Emphasis>-element salts in organic and aqueous–organic solvents: II. Effect of halocomplex formation on solubility of cobalt bromide and chloride and nickel chloride

Solubility of salts in the systems MCl₂–H₂O–Solv (M = Co, Ni) and CoBr₂–H₂O–Solv (Solv = dimethyl sulfoxide, dimethyl formamide, and dimethyl acetamide) at 25°C was measured experimentally. Dominating species of cobalt and nickel halides existing in various concentration regions were identified by analysis of electron absorption spectra. It was shown that the major factor defining solubility is the interaction of halocomplexes of metal ions with solvent molecules.     

Crystal structure and vibrational spectra of M[VO<Subscript>2</Subscript>(SeO<Subscript>4</Subscript>)(H<Subscript>2</Subscript>O)<Subscript>2</Subscript>]·H<Subscript>2</Subscript>O (M = K,Rb, NH<Subscript>4</Subscript>)

By the hydration of MVO(SeO₄)₂ with saturated water vapors at room temperature a series of isostructural complex compounds of vanadium(V) of the composition M[VO₂(SeO₄)(H₂O)₂]·H₂O (K, Rb, NH₄) are synthesized and their physicochemical properties are studied. Based on the X-ray and neutron diffraction data, it is found that their crystal structure is composed of VO₆ octahedra linked in infinite chains by bridging SeO₄ tetrahedra. Each of the VO₆ octahedra has two short terminal V-O bonds forming a bent dioxovanadium group VO₂⁺. Two water molecules are coordinated by vanadium and one molecule is out of the first coordination sphere in the interchain space. The vibrational spectra of the studied compounds are completely consistent with their structural features.     

Solution-solid phase equilibrium in the systems MBr<Subscript>2</Subscript>-NR<Subscript>4</Subscript>Br-H<Subscript>2</Subscript>O (M = Cd,Cu, Co; R = Me,Et, Bu) at 25°C

The solubility diagrams in ternary MBr₂-NR₄Br-H₂O systems (M = Cd, Co; R = Me, Et, Bu) at 25°C were determined by isothermal saturation. The composition and crystallization range of solid compounds occurring in equilibrium with the liquid phase were found. The effects of ion hydration, association of tetraalkylammonium salts, and complex formation with d-elements on the solution-solid phase equilibrium were estimated.     

Synthesis and molecular structure of niobocene(tricarbonyl)(π-cyclopentadienyl)molybdenum with metalmetal bond and unusual coordination of carbonyl groups

(C₅H₅)₂NbBH₄ reacts with C₅H₅M(CO)₃Me in toluene solution in the presence of Et₃N to give binuclear complexes (C₅H₅)₂NbM(CO)₃C₅H₅ where M is Mo or W (IV and V, respectively). The structure of IV has been studied by X-ray diffraction (the crystals are orthorhombic, a 12.748(5), b 16.745(6), c 14.314 $\text{A/ac>}\text{?}$;; Z = 8, space group of Pbca, automatic difractometer Syntex P2_I, λ(Mo-K_α, 1382 reflections, R = 0.056, R_w = 0.058). Molecule IV contains a wedge-like sandwich (π-C₅H₅)₂Nb (NbC 2.37–2.48, CC (av) 1.42 $\text{A/ac>}\text{?}$;, angle between ring planes 49°) linked with the (π-C₅H₅)Mo(CO) fragment by a direct NbMo bond (3.073 $\text{A/ac>}\text{?}$;) and two bridging CO groups, one nonsymmetrically bonded through the carbon atom only (CO 1.17, NbC 2.53, MoC 2.02 $\text{A/ac>}\text{?}$;) and the other σ-bonded to Mo (MoC 1.944 $\text{A/ac>}\text{?}$;) and π-bonded to Nb (CO 1.22, NbC 2.22, NbO 2.26 $\text{A/ac>}\text{?}$;). Three types of carbonyl groups present in IV give rise to strong IR bands at 1870, 1700 and 1560 cm^?1 assigned to the terminal, μ-bridging and σ, π-bridging CO groups respectively. Complex IV has a similar structure. The electronic structure of IV and its dissociation across the NbMo bond are discussed.     

Comparative analysis of solubility in CuCl-MCl-H2O systems at 25°C (M+ = Li+, Cs+, NH 4 + )

Solubility in the ternary system CuCl-NH₄Cl-H₂O at 25°C was determined by the method of isothermal lifting of oversaturation. A comparative analysis of solubility in this system and the previously studied systems CuCl-MCl-H₂O (M⁺ = Li⁺, Na⁺, K⁺, Cs⁺) was made. The results obtained were interpreted in terms of competition between hydration, association, and complexation processes in water-salt systems.