On the relationship between the structures of CuII complexes and their chemical transformations

The thermal decomposition of the complexes M ₂ ^I Cu(SO₄)₂ · 6 H₂O and M₂Ni(SO₄)₂ · · 6 H₂O (M^I=NH₄, K, Rb, Tl) containing the complex cation M^II(H₂O)₆ ²+ (M^Il = =Cu, Ni) was studied. The values of the experimental activation energyE obtained for the dehydration reactions of both complex cations were found to be influenced in different ways by the outer-sphere cations present. It was therefore concluded that the activation energy of the decomposition of Cu(H₂O)₆ ²⁺ depends on the degree of tetragonal distortion of this cation, which increases with the ionic radius of cation M^I. TheΔH values of the studied reactions depend less on the structures of the coordination polyhedra.     

On the relationship between the structures of Cu(II) complexes and their chemical transformations

The experimental activation energies (E ^*) of dehydration of Cu(NH₃)₄(H₂O)SO₄, Cu(en)₂(H₂O)X₂ (X=Cl^?, Br^?), Cu(en)(H₂O)₂SO₄, Cu(py)₂(H₂O)₂SO₄, CuCl₂ · 2H₂O and M ₂ ^I CuCl₄ · 2H₂O (M ^I =NH₄, K, Rb) were obtained from their non-isothermal thermogravimetric curves using the Coats-Redfern method. TheseE ^* values were compared with known data on the structures of the Cu(II) coordination polyhedra in the above complexes. No dependence of theE ^* values was found on either the central atom — released ligand bond length, or the number and lengths of the hydrogen bonds formed by the released water molecules. However, it was found that it is justified to seek some relationship between theE ^* values and the anisotropic temperature factors of the donor atoms of the ligands split off.     

Some studies on thallium oxalates. I. Thermal decomposition of ammonium bisoxalatothallate(III)

Trivalent thallium is precipitated in the presence of 0.1 M HNO₃ (or 0.05 M H₂SO₄) and O.1 M NH₄NO₃ (or 0.05 M (NH₄)₂SO₄) with oxalic acid. The chemical analysis of the salt obtained correspondens to the formula, NH₄[Tl(C₂O₄)₂]·3H₂O. The thermal decomposition studies of the complex indicate the formation of the intermediates ammonium thallous oxalate (stable from 150° to 160°C) and thallous oxalate (stable up to 290°C) and the final product to be a mixture of 25% of thallous oxide and 75% of thallic oxide (stable from 450° to 650°C). The infrared absorption spectra, X-ray diffraction patterns, microscopic observations and the electrical resistance measurements are used to characterise the complex and the intermediates of its thermal decomposition.     

Kinetics of isotope exchange between [3-(iodophenyl)methyl]guanidine (mIBG) and [131I]-iodide

The reaction of isotope exchange between [3-(iodophenyl)methyl]guanidine, mIBG, and [¹³¹]-iodide in relatively concentrated solutions, in the presence of different ammonium salts, in a closed system, over the temperature range from 130 to 150°C, has been investigated. The reaction occurs either with (NH₄)₂SO₄ or CH₃COOH, which indicates that the reaction goes through some intermediate stages. Kinetic studies show the influence of the additives. The activation energies for the reaction with (NH₄)₂SO₄/H₂O, (NH₄)₂SO₄/CH₃COOH and CH₃COOH are 121.1, 115.1 and 84.5 kJ·mol^–1, respectively.     

Crystal structure of fluorosulfate complex compounds of indium(III) M<Subscript>2</Subscript>[InF<Subscript>3</Subscript>(SO<Subscript>4</Subscript>)H<Subscript>2</Subscript>O] (M = K,NH<Subscript>4</Subscript>)

The crystal structures of isostructural mixed-ligand fluorosulfate complex compounds of indium(III) M₂[InF₃(SO₄)H₂O] (M = K, NH₄), formed of K⁺ cations, NH₄ ⁺ respectively, and complex [InF₃(SO₄)H₂O]^2– anions are determined. In the complex anion, the indium atom surrounded by three F atoms, the oxygen atom of the coordinated H₂O molecule, and two oxygen atoms of the bridging sulfate group forms a slightly distorted octahedron (CN 6). Via alternating bridging SO₄ groups, the polyhedra of In(III) atoms are arranged in polymer chains. The O–H???F hydrogen bonds organize the chains in a three-dimensional network. The K⁺ and NH₄ ⁺ cations are located in the structure framework and additionally strengthen it.     

Extraction studies of antimony bromide into benzene

Antimony(III) can be extracted rapidly and quantitatively into benzene from a 10 M H₂SO₄–0.03 M HBr system. The extracted antimony bromide has an antimony to bromine ratio of 1:3. Under the above optimum conditions for extraction of antimony, the behaviour of 35 other elements was studied; As³⁺, Ge⁴⁺, Se⁴⁺, and Sn²⁺ were extracted almost quantitatively, and the percentage extraction of Hg²⁺, Bi³⁺, and Te⁴⁺ was 74.1%, 10% and 5.5% respectively. The extraction of the elements into benzene from a 5 M H₂SO₄–0.01 M KI system was also investigated, A comparison of the two systems is given.     

DSC investigation of the thermal behaviour of (NH4)2SO4, NH4HSO4 and NH4NH2SO3

Gaseous products evolved from (NH₄)₂SO₄, NH₄HSO₄ and NH₄NH₂SO₃ during successive heating and cooling cycles were flushed with inert gas into analyzer Dräger tubes hooked tightly to the terminal port of the DSC cell base. This simple procedure allowed the starting temperature of the decomposition to be determined and the amount of the individual gases in the mixture to be identified and even estimated. NH₄NH₂SO₃ at 523 K in humid air produced HNH₂SO₃ initially and, on further cycling, (NH₄)₂SO₄ and NH₄HSO₄ also appeared. The ΔH_f values for NH₄HSO₄ were (kJ mole^?1): in an airtight sample holder 12.67, in a dry argon atmosphere 11.93, and in a static air atmosphere 10.92. Endothermic peaks for (NH₄)₂SO₄ and 498 and 411 K represented the incongruent melting point and the polymorphic transition of (NH₄)₂SO₄·NH₄HSO₄. After the first heating in air to 530 K, (NH₄)₂SO₄ and NH₄HSO₄ exhibited closely similar cyclic DSC curves. The endothermic peaks at about 393–420 K may be assigned to different combinations of (NH₄)₂SO₄ and NH₄HSO₄.     

Investigation of the surface properties of platinum,rhodium and iridium electrodes in hydrofluoric acid solutions

The charging curves, the potentiodynamic curves and the isoelectric potential shifts have been measured on Pt, Rh and Ir electrodes in HF and HF + KF solutions in a Teflon cell. From the obtained data, the Γ_H⁺?? curves and the Δσ?? curves of the first kind have been calculated by means of the thermodynamic theory of the hydrogen electrode. The Γ_H⁺ values in 0.14 M HF and 0.3 M HF + 0.12 M KF are much less than in 0.005 M H₂SO₄ and 0.005 M H₂SO₄ + 0.5 M K₂SO₄ solutions. In the presence of F^? anions, the potentials ?_ε=0 and ?_Q=0 are by 25–55 mV more anodic than in the presence of SO^2?₄ anions. In an acidified fluoride solution the values of σ are higher than in an acidified sulfate solution. The analysis of the results obtained leads to the conclusion that on platinum metals the fluoride anions in the ?_r region investigated (from ?_r = 0 to ?_r = 900 mV) are the most weakly adsorbed anions.     

Synthese und Struktur von Hydrogensulfaten des Typs M(HSO4)(H2SO4) (M = Rb,Cs und NH4)

Synthesis and Structure of Hydrogen Sulfates of the Type M(HSO₄)(H₂SO₄) (M = Rb, Cs and NH₄) From the binary systems M₂SO₄/H₂SO₄ (M = Rb, Cs, NH₄), three new hydrogen sulfates of the type M(HSO₄)(H₂SO₄) could be synthesized and structural characterized. The rubidium and caesium compounds are isotypic whereas NH₄(HSO₄)(H₂SO₄) is topologically very similar to both. All three compounds crystallize with nearly identical cell parameters [Rb: a = 7.382(1), b = 12.440(2), c = 7.861(2), β = 93.03(3); Cs: a = 7.604(1), b = 12.689(2), c = 8.092(2), β = 92.44(3); NH₄: a = 7.521(3), b = 12.541(5), c = 7.749(3), β = 92.74(3)], in the monoclinic space group P2₁/c, There exist two kinds of SO₄-tetrahedra: HSO₄^? anions (S1) and H₂SO₄-molecules (S2). The HSO₄^? anions form hydrogen bridged zigzag chains. In the case of the Rb and Cs compounds, the H₂SO₄ molecules connect these chains forming double layers. The metal atoms are coordinated by 9 O-atoms with M? O-distances of 2.97 – 3.39 Å (Rb) and 3.13 – 3.51 Å (Cs). In the ammonium compound additional hydrogen bonds are formed originating from the NH₄⁺ cation. This finally leads to the formation of S2? NH₄⁺ chains (parallel to the S1 chains) as well as to a three-dimensional connection of both kinds of chains.     

Structural and vibrational studies of Li[Kx(NH4)1−x]SO4 and Li2KNH4(SO4)2 mixed crystals

Mixed crystals of Li[K_x(NH₄)_1−x]SO₄ have been obtained by evaporation from aqueous solution at 313 K using different molar ratios of mixtures of LiKSO₄ and LiNH₄SO₄. The crystals were characterized by Raman scattering and single-crystal and powder X-ray diffraction. Two types of compound were obtained: Li[K_x(NH₄)_1−x]SO₄ with x?0.94 and Li₂KNH₄(SO₄)₂. Different phases of Li[K_x(NH₄)_1−x]SO₄ were yielded according to the molar ratio used in the preparation. The first phase is isostructural to the room-temperature phase of LiKSO₄. The second phase is the enantiomorph of the first, which is not observed in pure LiKSO₄, and the last is a disordered phase, which was also observed in LiKSO₄, and can be assumed as a mixture of domains of two preceding phases. In the second type of compound with formula Li₂KNH₄(SO₄)₂, the room-temperature phase is hexagonal, symmetry space group P6₃ with cell-volume nine times that of LiKSO₄. In this phase, some cavities are occupied by K⁺ ions only, and others are occupied by either K⁺ or NH₄⁺ at random. Thermal analyses of both types of compounds were performed by DSC, ATD, TG and powder X-ray diffraction. The phase transition temperatures for Li[K_x(NH₄)_1−x]SO₄x?0.94 were affected by the random presence of the ammonium ion in this disordered system. The high-temperature phase of Li₂KNH₄(SO₄)₂ is also hexagonal, space group P6₃/mmc with the cell a-parameter double that of LiKSO₄. The phase transition is at 471.9 K.     

Tabulation of infrared spectral data : David Dolphin and Alexander E. Wick,John Wiley,New York,London, Sydney and Toronto, 1977, pp. xvi + 549, price £14.65

The infrared spectra of the isotopically isolated NH₃D⁺ and HDO species have been examined in seven ammonium Tutton salts. The observed spectra are in good agreement with predictions based on the known crystallographic features of these salts. Linear regression of the ND stretching frequencies v₁(NH₃D⁺) of the isotopically isolated NH₃D⁺ ion on hydrogen-bonded distance d(N ? O) indicated the existence of a correlation ; subsequent fitting of the data to a more plausible empirical function v₁(NH₃D⁺) = v_1,∞,-k₁ exp(-k₂,d) resulted in a coefficient of determination of 0.94 and a standard deviation of 10 cm^?1 for the goodness of fit. The structural differences caused by the distortion of the metal coordination octahedron in the copper(II) Tutton salts are discussed. For this purpose the spectra of isotopically dilute HDO in the salts M₂ⁱ[Cu(H₂O)₆](SO₄)₂ (Mⁱ = K, Rb, Cs) have also been measured. No evidence of phase transformations between room and liquid-nitrogen temperatures was detected in the spectra of any of the saltri studied in this work.     

Vibrational behavior of matrix-isolated ions in Tutton compounds. V. Infrared spectroscopic study of NH4+ and SO42− ions included in zinc sulfates and selenates

Infrared spectra of K₂Zn(SeO₄)₂·6H₂O and (NH₄)₂Zn(SeO₄)₂·6H₂O containing SO₄^2? guest ions and those of K₂Zn(SO₄)₂·6H₂O and K₂Zn(SeO₄)₂·6H₂O containing NH₄⁺ guest ions are presented and discussed in the region of the stretching modes ν₃ and ν₁ of the sulfate ions and in the region of asymmetric bending modes ν₄ of the NH₄⁺ ions, respectively. The SO₄^2? ions matrix-isolated in the selenate matrices (approximately 2 mol%) exhibit three bands for ν₃ and one band for ν₁ in agreement with the low site symmetry C₁ of the selenate host ions. The NH₄⁺ guest ions included in the potassium sulfate matrix are characterized also with three site symmetry components of ν₄. However, the ammonium ions in (NH₄)₂Zn(SeO₄)₂·6H₂O as well as those included in K₂Zn(SeO₄)₂·6H₂O display four infrared bands corresponding to ν₄ probably due to some kind of disorder of the ammonium ions. The extent of energetic distortion of the isomorphously included sulfate ions as deduced from the values of Δν₃ (site-group splitting) and Δν_max (the difference between the highest and the lowest wavenumbered components of the stretching modes) are commented. The spectroscopic experiments reveal that the SO₄^2? guest ions are weaker distorted in the potassium selenate matrix than the same ions in the neat potassium sulfate due to the larger unit-cell volumes of the selenate compounds. However, the SO₄^2? guest ions are stronger distorted in the ammonium selenate matrix as compared to the same ions in the neat ammonium sulfate owing to the formation of hydrogen bonds between the SO₄^2? guest ions and the NH₄⁺ host ions. The analysis of the spectra shows that the band positions of the water librations in the host potassium compounds are affected by the included ammonium cations. The formation of the hydrogen bonds between the NH₄⁺ guest ions and the XO₄^2? host ions leads to a decrease in the proton acceptor capabilities of the anions (anti-cooperative or proton acceptor competitive effect) and as a result the hydrogen bonds formed by the water molecules weaken on going from the neat potassium compounds to the mixed crystals K_1.8(NH₄)_0.2Zn(SO₄)₂·6H₂O and K_1.8(NH₄)_0.2Zn(SeO₄)₂·6H₂O (the bands corresponding to water librations are broadened and shifted to lower frequencies).     

The Phase Diagram and the Application for the Quaternary System K+, $$ {\text{NH}}{_4^{+}} $$//Cl−, $$ {\text{SO}}{_4^{2 -}} $$SO42-–H2O at 80.0 °C

The solubilities in the quaternary system K⁺, \( {\text{NH}}{_4^{+}} \)//Cl^?, \( {\text{SO}}{_4^{2-}} \)–H₂O and its two ternary subsystems NH₄Cl–KCl–H₂O, (NH₄)₂SO₄–K₂SO₄–H₂O at 80.0 °C were measured using the isothermal dissolution equilibrium method under atmospheric pressure, and the corresponding phase diagrams were plotted. In the phase diagram of the NH₄Cl–KCl–H₂O system, there are three crystalline zones, which correspond to (K_1?m,(NH₄)_m)Cl, ((NH₄)_n,K_1?n)Cl and the co-existence zone of (K_1?m,(NH₄)_m)Cl and ((NH₄)_n,K_1?n)Cl, respectively. In the phase diagram of the (NH₄)₂SO₄–K₂SO₄–H₂O system, there is only one crystalline zone for (K_1?t,(NH₄)_t)₂SO₄. In the phase diagram of the K⁺, \( {\text{NH}}{_4^{+}} \)//Cl^?, \( {\text{SO}}{_4^{2-}} \)–H₂O system, there are three crystal zones, which correspond to (K_1?t,(NH₄)_t)₂SO₄, (K_1?m,(NH₄)_m)Cl and ((NH₄)_n,K_1?n)Cl, respectively. According to the analysis and the calculations for the phase diagrams of the K⁺, \( {\text{NH}}{_4^{+}} \)//Cl^?, \( {\text{SO}}{_4^{2 -}} \)–H₂O system at 80.0 °C and 50.0 °C, this paper proposes a technological process. In the process, the (K_1?t,(NH₄)_t)₂SO₄ can be prepared at 80.0 °C and the ((NH₄)_n,K_1?n)Cl can crystallize out at 50.0 °C. The mass fraction of K₂SO₄ in product L₁ (K_1?t,(NH₄)_t)₂SO₄ (t?=?0.1465) is 88.48%. The composition of solid solutions in the K⁺, \( {\text{NH}}{_4^{+}} \)//Cl^?, \( {\text{SO}}{_4^{2 -}} \)–H₂O system was experimentally determined and then theoretical calculations about the process can be carried out.     

Study on the reactions of fluoroalkanesulfonyl azides with pyrazine and its derivatives

The thermal reactions of fluoroalkanesulfonyl azides R_fSO₂N₃ with pyrazine and its derivatives are studied in detail. All the reactions involved the fluoroalkanesulfonyl nitrene intermediates R_fSO₃N: which was captured by pyrazine to give the pyrazinium N-fluoroalkanesulfonyl ylides C₄NH₄N⁺-⁻NSO₂R_f and hydrogen abstraction product R_fSO₂NH₂, but no corresponding N-pyrazinyl fluoroalkanesulfonyl amide derivatives R_fSO₂NHC₄N₂H₃ were isolated. Excess azides did not afford the bisN-ylide product R_fSO₂N⁻-⁺NC₄H₄N⁺-⁻NSO₂R_f.     

Measurements of HO2 uptake coefficient on aqueous (NH4)2SO4 aerosol using aerosol flow tube with LIF system

Laboratory studies of HO₂ uptake coefficients, γ(HO₂), were conducted at room temperature using an aerosol flow tube coupled with a laser induced fluorescence (LIF) system. The measurement was conducted with atmospherically relevant HO₂ concentrations (～1 × 10⁹ molecule/cm³) at 51% RH. The measured γ(HO₂) onto aqueous (NH₄)₂SO₄ aerosol was 0.001 ± 0.0007, which was consistent with the relatively low first-order loss rate of HO₂ onto aqueous (NH₄)₂SO₄ aerosol. The γ(HO₂) was elevated with increase of Cu(II) concentrations in aqueous (NH₄)₂SO₄ aerosol. The threshold of Cu(II) concentration was 10^?3 mol/L for the dramatic increase of γ(HO₂). It was found that γ(HO₂) reached 0.1 when Cu(II) concentration in aerosol was larger than 10^?3 mol/L, suggesting that γ(HO₂) is very sensitive to concentration of transition metal ions in aerosol.     

Temperature dependence of121Sb nuclear quadrupole resonance frequencies in the spectra of M2Sb2SO4F6 (M = K,Rb, NH4)

The temperature dependence of the frequencies of¹²¹Sb nuclear quadrupole resonance in the spectra of M₂Sb₂SO₄F₆ (M = K, Rb, NH₄) was studied in the temperature range from 77 to 340 K. A secondary phase transition was found above 320 K for (NH₄)₂SO₄F₆.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1831–1833, October, 1994.This study was sponsored by the Russian Foundation for Basic Research (Grant No. 93-03-4394).     

Structural Characterization of Some Coinage Metal(I) Thiosulfate Complexes, $\rm M^{1}_{a}M\rm ^{2}_{b}(X_{c}) (S_{2}O_{3})_{d}(\cdot eS)$ (M1 = Group 1 Cation,X = Univalent Anion,M2 = CuI,AgI, S = Solvent)

Building on previous single crystal X‐ray structure determinations for the group 1 salts of complex thiosulfate/univalent coinage metal anions previously defined for (NH₄)₉AgCl₂(S₂O₃)₄, NaAgS₂O₃·H₂O and Na₄[Cu(NH₃)₄][Cu(S₂O₃)₂]·NH₃, a wide variety of similar salts, of the form , M¹ = group 1 metal cation, M² = univalent coinage metal cation (Cu, Ag), (X = univalent anion), most previously known, but some not, have been isolated and subjected to similar determinations. These have defined further members of the isotypic, tetragonal series, for M¹ = NH₄, M² = Cu, Ag, X = NO₃, Cl, Br, I, together with the K/Cu/NO₃ complex, all containing the complex anion [M²(SSO₃)₄]^7? with M² in an environment of symmetry, Cu, Ag‐S typically ca. 2.37, 2.58Å, with quasi‐tetrahedral S‐M‐S angular environments. Further salts of the form , n = 1‐3, have also been defined: For n = 3, M² = Cu, M¹/x = K/2.25 or 1 5/6, NH₄/6, (and also for the (NH₄)₄Na/4H₂O·MeOH adduct) the arrays take the form with distorted trigonal planar CuS₃ coordination environments, Cu‐S distances being typically 2.21Å, S‐Cu‐S ranging between 105.31(4)–129.77(4)°; the silver counterparts take the form for M¹ = K, NH₄. For n = 2, adducts have only been defined for M² = Ag, the anions of the M¹ = Na, K adducts being dimeric and polymeric respectively: Na₆[(O₃SS)₂Ag(μ‐SSO₃)₂Ag(SSO₃)]·3H₂O, K₃[Ag(μ‐SSO₃)₂]_(∞|∞)·H₂O; a polymeric copper(I) counterpart of the latter is found in Na₅Cu(NO₃)₂(S₂O₃)₂ ≡ 2NaNO₃·Na₃[Cu(μ‐SSO₃)₂]_(∞|∞). For n = 1, NaAgS₂O₃, the an‐ and mono‐ hydrates, exhibit a two‐dimensional polymeric complex anion in both forms but with different contributing motifs. (NH₄)₁₃Ag₃(S₂O₃)₈·2H₂O takes the form (NH₄)₁₃[{(O₃SS)₃Ag(μ‐SSO₃)}₂Ag], a linearly coordinated central silver atom linking a pair of peripheral [Ag(SSO₃)₄]^7? entities. In Na₆[(O₃SS)Ag(μ‐SSO₃)₂Ag(SSO₃)]·3H₂O, the binuclear anions present as Ag₂S₄ sheets, the associated oxygen atoms being disposed to one side, thus sandwiching layers of sodium ions; the remarkable complex Na₅[Ag₃(S₂O₃)₄]_(∞|∞)·H₂O is a variant, in which one sodium atom is transformed into silver, linking the binuclear species into a one‐dimensional polymer. In (NH₄)₈[Cu₂(S₂O₃)₅]·2H₂O a binuclear anion of the form [(O₃SS)₂Cu(μ‐S.SO₃)Cu(SSO₃)₂]^8? is found; the complex (NH₄)₁₁Cu(S₂O₃)₆ is 2(NH₄)₂(S₂O₃)·(NH₄)₇[Cu(SSO₃)₄]. A novel new hydrate of sodium thiosulfate is described, 4Na₄S₂O₃·5H₂O, largely describable as sheets of the salt, shrouded in water molecules to either side, together with a redetermination of the structure of 3K₂S₂O₃·H₂O.     

Proton NMR study of molecular dynamics in ammonium tribromo stannate (NH4SnBr3)

The proton second moment M₂ and spin-lattice relaxation time T₁ have been measured in ammonium tribromo stannate (NH₄SnBr₃) in the temperature range 77–300 K, to determine the ammonium dynamics. The continuous wave signal is strong and narrow at 77 and 300 K but has revealed an interesting intensity anomaly between 210 and 125 K. T₁ shows a maximum (13 s) around 220 K. No minimum in the T₁ vs 1000/T plot was observed down to 77 K. M₂ and T₁ results are interpreted in terms of NH⁺₄ ion dynamics. The activation energy E_a for NH⁺₄ ion reorientation is estimated to be 1.4 kcal mol⁻¹.     

NMR relaxation study of the phase transitions and relaxation mechanisms of the alums MCr(SO4)2·12H2O (M=Rb and Cs) single crystals

The physical properties and phase transition mechanisms of MCr(SO₄)₂·12H₂O (M=Rb and Cs) single crystals have been investigated. The phase transition temperatures, NMR spectra, and the spin-lattice relaxation times T₁ of the ⁸⁷Rb and ¹³³Cs nuclei in the two crystals were determined using DSC and FT NMR spectroscopy. The resonance lines and relaxation times of the ⁸⁷Rb and ¹³³Cs nuclei undergo significant changes at the phase transition temperatures. The sudden changes in the splitting of the Rb and Cs resonance lines are attributed to changes in the local symmetry of their sites, and the changes in the temperature dependences of T₁ are related to variations in the symmetry of the octahedra of water molecules surrounding Rb⁺ and Cs⁺. We also compared these ⁸⁷Rb and ¹³³Cs NMR results with those obtained for the trivalent cations Cr and Al in MCr(SO₄)₂·12H₂O and MAl(SO₄)₂·12H₂O crystals.