Two alkali metal chlorites,LiClO2 and KClO2

The structures of tetragonal (P4₂/ncm) lithium chlorite, LiClO₂, and orthorhombic (Cmcm) potassium chlorite, KClO₂, have been determined by single‐crystal X‐ray analyses. In LiClO₂, the Li atom is at a site of symmetry, while in KClO₂, the K atom is at a site with 2/m symmetry. In both compounds, the unique Cl and O atoms are at sites with mm and m symmetry, respectively. The structure of LiClO₂ consists of layers of Li⁺ cations coordinated by ClO₂⁻ anions. In contrast, the structure of KClO₂ contains pseudo‐layers of K⁺ and ClO₂⁻ ions containing four short K—O distances. The Li⁺ and K⁺ cations are surrounded by four and eight chlorite O atoms in tetrahedral and distorted cubic coordination environments, respectively.     

Vibrational spectra of molten and aqueous NaClO3 and KClO3

Raman spectra of molten NaClO₃ and KClO₃ and of aqueous solutions of these salts were measured over the frequency interval from 50 to 1200 cm⁻¹|. Infrared emission spectra of the molten chlorates and of chlorate-nitrate mixtures were recorded, and absorption spectra of aqueous sodium and potassium chlorate also were determined. The ν₃(e) and ν₄(e) modes of ClO⁻₃ were split in the molten salt and aqueous solution spectra, and a single, weak band was observed between ca. 80 and 200 cm⁻ in the Raman spectra of molten NaClO₃ and KClO₃.     

FTIR study of ion solvation and ion-pair formation in alkaline and alkaline earth metal salt solutions in acetonitrile

The IR spectra of alkaline and alkaline earth metal perchlorate and of lithium bromide solutions in acetonitrile, obtained with the help of FTIR measurements in the region of the C-N stretching mode of the solvent, reveal bands produced by acetonitrile molecules in the solvation shells and bands of ClO ₄ ^– ions in contact and solvent separated ion pairs. The shift and the attenuation of the C-N stretching band of acetonitrile at 2254 cm^–1 is used for the calculation of cation solvation numbers for Li⁺(4), Na⁺(4), Mg²⁺(6), Ca²⁺(6), and Ba²⁺(6). No solvation is assumed for the contact ion pairs of LiClO₄, LiBr, NaClO₄, Mg(ClO₄)₂, Ca(ClO₄)₂, and Ba(ClO₄)₂. The association constants of the symmetrical electrolytes are compared to those obtained from other methods.     

Sequential and simultaneous determination of bromate and chlorite (DBPs) by flow techniques: kinetic differentiation

3-3′-Dimethoxybenzidine (o-dianisidine, ODA) is oxidised by Br₂, among other oxidants, generating a compound that absorbs at 450 nm, while the non-oxidised reagent absorbs in the UV region. This reaction has been used previously as the basis of a continuous-flow method for the determination of bromate in ozonised water, with a detection limit lower than the maximum permitted for drinking water (10 μg L⁻¹). The only interference observed in the method was that due to the chlorite ion (ClO₂⁻), which generated the same ODA bromation product. Thus, in systems in which O₃ is employed as a disinfectant and disinfection is later enhanced with ClO⁻ and ClO₂, there exists the possibility of finding BrO₃⁻ and ClO₂⁻, oxoanions generated as subproducts. The kinetic behaviour of the reaction between bromate and chlorite with bromine in acidic medium is different, allowing the proposal of a continuous-flow method for the simultaneous or sequential determination of both subproducts in water purification systems. None of the other subproducts interfered in the reaction. Kinetic differentiation was achieved by combining the temperature of the reaction and the length of the coils, after which it was possible to determine both analytes sequentially within a concentration range of 6–160 μg L⁻¹.     

Synthesis of new macrocyclic lactones and their extraction study

New macrocyclic lactones were synthesized by reaction of 3-bromo-5-(5-tert-butyl-2-hydroxybenzyl)biphenyl-4-ol with appropriate polyethylene glycol-based dicarboxylic acid dichlorides, and their complexes with Mg(ClO₄)₂·6H₂O, Pb(SCN)₂, NaClO₄·H₂O, and KClO₄ were prepared. The macrocyclic ligands were evaluated as extractants in the transfer of Li⁺, Na⁺, K⁺, Cu²⁺, Ni²⁺, and Hg²⁺ picrates from aqueous to organic phase. Published in Russian in Zhurnal Organicheskoi Khimii, 2008, Vol. 44, No. 9, pp. 1400–1405. The text was submitted by the authors in English.     

Conductance studies of some ammonium and alkali metal salts in propylene carbonate

Conductance data are reported for NaI, KI, RbI, CsI, NH₄I, NaClO₄, and KClO₄ in propylene carbonate at 25°C in the concentration range 1×10^–4 –8.3×10^–3M. Analysis of the data with the current conductance theories indicates negligible ion-association, strong cation-solvent and weak anion-solvent interactions.     

Diazabicyclo[2.2.2]octane-1,4-diium occluded in cubic anionic coordinated framework: the role of trifurcated hydrogen bonds of N–HO and C–HO

A unique coordinated molecular capsule compound is synthesized and characterized by X-ray diffraction. The compound crystallizes in cubic space group of Pa-3 with a=14.348(1), b=14.348(1), c=14.348(1) Å, V=2953.8(4) ų, Z=8. The diazabicyclo[2.2.2]octane-1,4-diium is occluded in the cubic anionic coordinated framework of K⁺ and (ClO₄)⁻ in a dimension of 7.174(1) Å, and assumes ordered feature. All of hydrogen atoms take parts in trifurcated hydrogen bonds of N–HO and C–HO type, respectively, the later being reported for the first time. The IR spectrum of the title compound shows significant shift of CH₂ vibrational bands, and are correlated with X-ray structural data.     

Three new copper(II)–nickel(II) heterodinuclear complexes with the <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N′</Emphasis>-bis(2-pyridyl-ethyl)oxamide dianion. Syntheses,spectra, and magnetic properties

Three new Cu(II)–Ni(II) heterodinuclear complexes: [Cu(PMoxd)Ni(phen)₂](ClO₄)₂ (1), [Cu(PMoxd)Ni(NO₂-phen)₂](ClO₄)₂ (2), [Cu(PEoxd)Ni(Me₂-bpy)₂](ClO₄)₂ (3), [where Cu(PMoxd)=N,N′-bis(pyridyl-methyl)oxamidatocopper(II), Cu(PExod)=N,N′-bis(2-pyridyl-ethyl)oxamidatocopper(II), phen=1,10-phenanthroline and NO₂-phen=5-nitro-1,10-phenanthroline and bpy=2,2′-bipyridine] were prepared and characterized by i.r. and electronic spectra, and by magnetic properties. The magnetic analysis was carried out by means of the theoretical expression of the magnetic susceptibility deduced from the spin Hamiltonian H=−2JS₁S₂, leading to J=−70.83 cm⁻¹ (1); −56.23 cm⁻¹ (2); −57.30 cm⁻¹ (3), indicating a weak antiferromagnetic spin–exchange interaction between Cu(II) and Ni(II) ions within three complexes.     

AB initio study of the structure, isomerism, and vibrational spectra of LiClO3, NaClO3, and KClO3

The geometrical structure, force fields, and vibrational spectra of the ClO ₃ ^? ion and LiClO₃, NaClO₃, and KClO₃ molecules are studied using the Hartree-Fock (HF) method and second-order Möller-Plesset (MP2) perturbation theory in double-zeta basis sets complemented with polarization and diffuse functions. Routes of intramolecular rearrangements corresponding to migration of the M⁺ cations around the ClO ₃ ^? anion are investigated. The calculations showed that the molecular structure of alkaline metal chlorates changes in the series LiClO₃ → NaClO₃ → KClO₃. The LiClO₃ molecule has an essentially bidentate configuration of C_s symmetry; the KClO₃ molecule has tridentate coordination of C_3v symmetry. The NaClO₃ molecule exists as two isomeric forms having similar energies: tridentate (C_3v) and bidentate (C_s) forms separated by a low potential barrier (199 cm^?1 ? HF, 170 cm^?1 ? MP2); the energy differences between the isomers are ΔE(C_s ? C_3v)=?0.5 (HF), 0.4 kJ/mole (MP2). The theoretical vibrational spectra of molecules agree with the available experimental data.     

Facile cation electro-insertion into layer-by-layer assembled iron phytate films

Molecular layer-by-layer assembly from pre-saturated aqueous solutions of Fe³⁺ and phytate is employed to build up iron phytate deposits on tin-doped indium oxide (ITO) electrodes. Globular films with approximately 1 nm growth per layer are observed by AFM imaging and sectioning. In electrochemical experiments the iron phytate films show well-defined voltammetric responses consistent with an immobilised Fe(III/II) redox system in aqueous (LiClO₄, NaClO₄, KClO₄, phosphate buffer) and in ethanolic (LiClO₄, NaClO₄, NBu₄ClO₄) electrolyte solutions. The Fe(III/II) redox system is reversible and cation insertion/expulsion occurs fast on the timescale of voltammetric experiments even for more bulky NBu₄⁺ cations and in ethanolic solution. Peak shape analysis and scan rate dependent midpoint potentials suggest structural changes accompanying the redox process and limiting propagation. Iron phytate is proposed as a versatile and essentially colourless cation electro-insertion material and as a potential energy storage material.     

Extraction of Sodium and Potassium Perchlorates with Dibenzo-18-crown-6 into Various Organic Solvents. Quantitative Elucidation of Anion Effects on the Extraction-Ability and -Selectivity

The constants for overall extraction into various diluents of low dielectric constants (K_ex) and aqueous ion-pair formation (K_MLA) of dibenzo-18-crown-6 (DB18C6)–sodium and potassium perchlorate 1:1:1 complexes (MLA) were determined at 25°C. The K_ex value was analyzed by the four underlying equilibrium constants. The K_MLA values were determined by applying our established method to this DB18C6/alkali metal perchlorate extraction system. The K_M(DB18C6)A value of the perchlorate is much greater for K⁺ than for Na⁺, and is much smaller than that of the picrate. The K_MLA value makes a negative contribution to the extractability of DB18C6 for MClO₄, whereas the value of the MLA distribution-constant does a major one. The partition behavior of M(DB18C6)ClO₄ obeys the regular solution theory. However, the M(DB18C6)ClO₄ complexes in the diluent of high dipole moment somewhat undergo the dipole–dipole interaction. DB18C6 always shows high extraction selectivity for KClO₄ over NaClO₄, which is governed largely by the much greater K_MLA value for K⁺ than for Na⁺. The K⁺ extraction-selectivity of DB18C6 over Na⁺ for perchlorate ions is comparable to that for picrate ions. By comparing this perchlorate system with the picrate one, the anion effects on the extraction-efficiency and -selectivity of DB18C6 for Na⁺ and K⁺ was discussed in terms of the fundamental equilibrium constants.     

Anionic Effects on Raman OD Stretching Spectra for Alcoholic LiX Solutions (X = Cl−, Br−, I−, ClO4 −, NO3 −, and CH3COO−)

Raman OD stretching spectra of alcoholic LiX (X = Cl^–, Br^–, I^–, ClO₄ ^–, NO₃ ^–, and CH₃COO^–) solutions (alcohols = methanol and ethanol) were measured in the liquid state at room temperature and in the glassy state at liquid nitrogen temperature. The effects of the anions on the Raman OD stretching spectra in these alcoholic solutions are investigated and the structural changes of the solutions are discussed. It is shown that the structure-breaking effects of anions on the intrinsic alcoholic structure increase in the order: Cl^– < Br^– < I^– < ClO₄ ^–. From spectral changes, it seems that CH₃COOLi exerts little effect on the liquid structure of the alcohol.     

Die kinetische polarographische Stufe des Urans in Gegenwart von Chlorat-Ionen

An increase of the 2nd polarographic uranium(VI) wave has been observed in the presence of chlorate ions in HClO₄–NaClO₄, or HClO₄–NaClO₄–NaCl supporting electrolyte, resp. The polarographic measurements at different temperatures and at various perchloric acid concentrations show that this increase is due to a kinetic U(III)-U(IV) current. The activation parameters of the U(III)-U(IV) oxidation reaction with ClO₃ ^– have been calculated usingKautecky's method.The approximately 5fold increase of the 2nd polarographic wave allows the determination of small amounts of uranium (10^–5–10^–6 mole/l).

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Mit 2 Abbildungen     

Compounds of nickel(II) with 5SR,7RS,12SR,14SR-5,12-dimethyl-7,14-diphenyl-1,4,8,11-tetraazacyclotetradecane, rmL: The structures of [Ni(rmL)](ClO4)2 · 0.5H2O and cis-[Ni(rmL)(acac)]ClO4

The imine functions of [Ni(mL¹)](ClO₄)₂ (mL¹ = meso-7RS,14SR-5,12-dimethyl-7,14-diphenyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene) are reduced by using NaBH₄ in acetonitrile/methanol to form the meso–meso and rac–meso isomeric cyclic tetramine complex cations [Ni(mmL²)]²⁺ and [Ni(rmL²)]²⁺ (mml² = 5RS,7RS,12SR,14SR- and rmL² = 5SR,7RS,12SR,14SR-5,12-dimethyl-7,14-diphenyl-1,4,8,11-tetraazacyclotetradecane) in ca. 8:1 proportions. [Ni(rmL²)]²⁺ is also prepared from rmL², formed in <1% yield by the reduction of mL¹ by NaBH₄ in ethanol. Square planar singlet ground state (S = 1) salts [Ni(rmL²)](ClO₄)₂ and [Ni(rmL²)][ZnCl₄] and triplet ground state (S = 3) trans-di-ligand octahedral compounds trans-[Ni(rmL²)X₂] ,μ-Y-trans-[Ni(rmL²)Y] and folded macrocycle compounds cis-[Ni(rmL²)(acac)]CIO₄ (acac⁻ = pentane-2,4-dionato), cis-[{Ni(rmL²)}₂(C₂O₄)](ClO₄)₂, cis-[Ni(rmL²)(H₂O)₂](ClO₄)₂ and cis-[Ni(rmL²)X₂], X⁻ = Cl⁻, Br⁻, are described. The S = 1 salt 1SR,4SR,5SR,7RS,8RS,11RS,12SR,14SR-[Ni(rmL²)](ClO₄)₂ · 0.5H₂O has a disordered structure with Ni(II) in square planar coordination by the nitrogen atoms of the macrocycle, in N-configuration III, with Ni–N_mean = 1.96(2) Å. The six-membered chelate rings both have chair conformations, with the phenyl substituents equatorially oriented and with the methyl substituents disordered over axial and equatorial orientations. The S = 3 compound cis-1SR,4SR,5SR,7RS,8SR,11SR,12SR,14SR-[Ni(rmL²)(acac)]ClO₄ has N-configuration V. The macrocycle is folded along N¹–Ni–N⁸, adjacent to the phenyl substituents {N1–Ni–N8 = 176.45(6), N4–Ni–N11 = 98.16(6)°}, with mean Ni–N = 2.09(2) Å and mean Ni–O = 2.121(5) Å. Both six-membered chelate rings have chair conformations with the methyl substituents equatorially oriented, while one has the phenyl substituent equatorially and the other has it axially oriented. The structures of the isomeric [M(rmL²)(acac)]ClO₄, [M(rrL²)(acac)]CIO₄ and [M(mmL²)(acac)]ClO₄ compounds are compared.     

Effect of Electrolytes on Redox Reactivity of Polypyrrole

Doping and dedoping characteristics of polypyrrole (PPy) formed electrochemically have been examined by means of energy-dispersive X-ray spectroscopy (EDS). Dodecylsulfate ions (DS⁻) and perchlorate ions (ClO⁻₄) were embedded simultaneously in PPy when both ions were present on the polymerization of pyrrole. Sequential formation of PPy in the single dopant system allowed PPy/ClO₄ to grow in the bulk of PPy/DS but not vice versa. DS⁻ was embedded not to leave the polymer on reduction but ClO⁻₄ moved in and out of the polymer on redox reaction. Cyclic voltammetry was employed to determine the redox reactivity of PPy in different electrolyte systems. NaClO₄ was a better electrolyte for cyclic redox reaction than LiClO₄ or KClO₄. NaCl was a good electrolyte for cyclic redox reaction but Cl⁻ failed to penetrate in the PPy/DS bulk on reoxidation. The cyclic redox reactivity lasted longest when PPy/DS was redox-cycled sequentially in the NaCl electrolyte system and then in the NaClO₄ system. © 1997 John Wiley & Sons, Ltd.     

A vibrational analysis of the MnO 4 − bands

Teltow'S [14,15] measurements of the permanganate bands are reanalyzed using the level scheme of Ballhausen and Liehr [2]. For KMnO ₄ dissolved in KClO ₄ the components of the first ¹ T ₂ state are found at 18050 cm^–1 18078 cm^–1 and 18043 cm^–1. The breathing frequency of the MnO _– ⁴ unit is in this state 768 ^–1. The electronic origin of the second ¹ T ₂ state is found at 30723 cm^–1 with a breathing frequency of 760 cm^–1.Evidence is further found for a ¹ T ₁ state with its split components located at 14446 cm^–1, 14526 cm^–1 and 14600 cm^–1. The breathing frequency is here found to be 800 cm^–1.Finally for KMnO ₄ dissolved in NaClO ₄ there are indications that one or two spin-triplets are located near 13200 cm^–1.

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Zusammenfassung TeltowS Messungen des Permanganatspektrums [14, 15] werden mit Hilfe des Termschemas von Ballhausen und Liehr [2] von neuem analysiert. Für KMn ₄ in KClO ₄ findet man die zum ersten ¹ T ₂-Zustand gehörenden Komponenten bei 18050, 18078 und 18043 cm^–1. Die Valenzschwingung des MnO _– ⁴ liegt hier bei 768 cm^–1. Der Ursprung des zweiten ¹ T ₂-Systems wird bei 30723 cm^–1 gefunden, die dazugehörige Valenzfrequenz ist 760 cm^–1.Bei 14446, 14526 und 14600 cm^–1 liegen offenbar die Komponenten eines ¹ T ₁-Terms, wozu eine Valenzfrequenz von 800 cm^–1 gehört.Schließlich findet man für KMnO ₄ in NaClO ₄ Anzeichen für ein oder zwei Spin-Tripletts um 13200 cm^–1.

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Résumé Les bandes d'absorption du permanganate, mesurées par Teltow [14,15], sont réanalysées à l'aide d'un système de termes proposé par Ballhausen et Liehr [2]. Pour KMnO ₄ dans KClO ₄, on trouve les composants du premier état ¹ T ₁ à 18050, 18078 et 18043 cm^–1. La vibration symétrique du MnO _– ⁴ dans cet état se situe à 768 cm^–1. L'origine électronique du second état ¹ T ₂ est trouvé à 30723 cm^–1, la fréquence oscillatrice correspondante est de 760 cm^–1.Un état ¹ T ₁ avec ses composants à 14446, 14526 et 14600 cm^–1 est mis en évidence, avec une vibration symétrique de 800 cm^–1.Finalement, au cas du KMnO ₄ dissous dans le NaClO ₄, il y a des indications pour un ou deux triplets de spin vers 13200 cm^–1.

     

Vibrational spectroscopic study of the arsenate mineral strashimirite Cu8(AsO4)4(OH)4·5H2O—Relationship to other basic copper arsenates

The basic copper arsenate mineral strashimirite Cu₈(AsO₄)₄(OH)₄·5H₂O from two different localities has been studied by Raman spectroscopy and complemented by infrared spectroscopy. Two strashimirite mineral samples were obtained from the Czech (sample A) and Slovak (sample B) Republics. Two Raman bands for sample A are identified at 839 and 856 cm⁻¹ and for sample B at 843 and 891 cm⁻¹ are assigned to the ν₁ (AsO₄³⁻) symmetric and the ν₃ (AsO₄³⁻) antisymmetric stretching modes, respectively. The broad band for sample A centred upon 500 cm⁻¹, resolved into component bands at 467, 497, 526 and 554 cm⁻¹ and for sample B at 507 and 560 cm⁻¹ include bands which are attributable to the ν₄ (AsO₄³⁻) bending mode. In the Raman spectra, two bands (sample A) at 337 and 393 cm⁻¹ and at 343 and 374 cm⁻¹ for sample B are attributed to the ν₂ (AsO₄³⁻) bending mode. The Raman spectrum of strashimirite sample A shows three resolved bands at 3450, 3488 and 3585 cm⁻¹. The first two bands are attributed to water stretching vibrations whereas the band at 3585 cm⁻¹ to OH stretching vibrations of the hydroxyl units. Two bands (3497 and 3444 cm⁻¹) are observed in the Raman spectrum of B. A comparison is made of the Raman spectrum of strashimirite with the Raman spectra of other selected basic copper arsenates including olivenite, cornwallite, cornubite and clinoclase.     

Structure of Ba Na Ethylenediaminetetraacetatocobaltate(III) Perchlorate, Na[Ba6(H2O)25][Co(Edta)]4(ClO4)9 · 5H2O

Crystals with uncommon composition NaBa₆[Co(Edta)]₄(ClO₄)₉ · 30H₂O (Edta⁴⁻ is ethylenediaminetetraacetic acid anion) were obtained with the following unit cell parameters: a = 14.8513(9) Å, b = 26.2361(15) Å, c = 15.1789(9) Å, α = 91.661(7)°, β = 113.035(7)°, γ = 89.897(7)°, space group P1¯. Each complex anion [Co(Edta)]⁻ is bonded through the carboxyl O atoms to five Ba atoms to give three-dimensional framework in a crystal. One perchlorate ion forms Ba-O-Cl-O-Ba bridge between the Ba atoms; four ClO ₄ ⁻ ions are isolated, while the remaining four ions act as monodentate ligands at the Ba atoms. The water molecules (25 in sum) complete the coordination sphere of the Ba atoms to eight-, nine-, or ten-vertex polyhedron. Four water molecules are in the closest surrounding of the Na atom, one H₂O molecule is isolated.__________Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 8, 2005, pp. 590–595.Original Russian Text Copyright © 2005 by Zabel, Poznyak, Pawlowski.     

Investigation of Protonation of the Tetraazamacrocyclic Complex of Gold(III) [Au(C14H22N4)]+ in Water. Synthesis and Crystal and Molecular Structures of [Au(C14H23N4)](ClO4)2

The equilibrium of protonation of tetraazamacrocyclic complex of gold(III) [AuL]⁺ (L = 5,7,12,14-tetramethyl-1,4,8,11-tetraazacyclotetradeca-4,6,11,13-tetraenato(2-)) in a water solution has been investigated. A monoprotonated tetraazamacrocyclic metallocomplex with two inequivalent (iminate and imine) six-membered chelate cycles and charge 1- was obtained and isolated for the first time. The compound [AuHL](ClO₄)₂ was characterized by chemical analysis, IR and UV-VIS spectroscopy, powder and single crystal X-ray diffraction. The proton was shown to be attached to the β-carbon of one of the two six-membered chelate rings of the macrocycle. Crystal data for [AuHL](ClO₄)₂ are: a = 7.693(1) Å, b = 17.366(2) Å, c =15.172(2) Å; β = 96.82(1)°, V = 2012.6(4) ų, Z = 4, d _calc = 2.123 g/cm³, space group P2₁/c. The structure is built from practically planar [Au(C₁₄H₂₃N₄)]²⁺ cations and perchlorate anions [ClO₄]⁻.Original Russian Text Copyright © 2004 by V. A. Afanasieva, I. V. Mironov, L. A. Glinskaya, R. F. Klevtsova, and L. A. Sheludyakova__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 6, pp. 1059–1066, November–December, 2004.     

EPR and optical absorption studies of Cr ions in d-gluconic acid monohydrate

EPR studies are carried out on Cr³⁺ ions doped in d-gluconic acid monohydrate (C₆H₁₂O₇·H₂O) single crystals at 77 K. From the observed EPR spectra, the spin Hamiltonian parameters g, |D| and |E| are measured to be 1.9919, 349 (×10⁻⁴) cm⁻¹ and 113 (×10⁻⁴) cm⁻¹, respectively. The optical absorption of the crystal is also studied at room temperature. From the observed band positions, the cubic crystal field splitting parameter Dq (2052 cm⁻¹) and the Racah interelectronic repulsion parameter B (653 cm⁻¹) are evaluated. From the correlation of EPR and optical data the nature of bonding of Cr³⁺ ion with its ligands is discussed.