Raman studies of molten salt hydrates: the beryllium and aluminium nitrate-water systems

Raman spectra of the liquid systems Be(NO₃)₂ · 20H₂O, Be(NO₃)₂ · 4H₂O, Al(NO₃)₃·20H₂O, and Al(NO₃)₃ · 9H₂O have been recorded. The spectra are analysed in terms of vibrational modes arising from water, the nitrate ion, the aquated metal ions and hydrolysis products. For the concentrated beryllium system, though not for the aluminium system, the spectra suggest a significant degree of proton transfer from [Be(OH₂)₄]²⁺ to NO₃^?. Solvent-separated metal-nitrate ion pairs appear to be present in all the systems studied.     

Synthesis,structure and magnetic properties of Ni2(NO3)4(APTY)4 (APTY=1,5-dimethyl-2-phenyl-4-{[(1 E )-pyridine-4-ylmethylene]amino}-1,2-dihydro-3 H -pyrazol-3-one)

A novel dinuclear nickel(II) complex Ni₂(NO₃)₄(APTY)₄ (1) (APTY?=?1,5-dimethyl-2-phenyl-4-{[(1E)-pyridine-4-ylmethylene]amino}-1,2-dihydro-3H-pyrazol-3-one), was synthesized by solvothermal reaction of Ni(NO₃)₂?·?6H₂O with APTY in methanol at 353?K. The structure consists of centrosymmetric dimers resulting from octahedrally coordinated Ni atoms bridged by APTY ligands. Weak intermolecular interactions (C–H?···?N, C–H?···?O hydrogen bonding, C–H?···?π and π–π stacking interactions) are responsible for a supramolecular assembly of molecules in the lattice. Magnetic measurements over 1.8–300?K show weak antiferromagnetic coupling between Ni(II) ions with J?=?2.969?cm^?1, g?=?2.280, θ?=??5.903.     

Kristallstrukturen des Sr(BrO3)2 · H2O,Ba(BrO3)2 · H2O,Ba(IO3)2 · H2O,Pb(CIO3)2 · H2O und Pb(BrO3)2 · H2O

Crystal Structure of Sr(BrO₃)₂ · H₂O, Ba(BrO₃)₂ · H₂O, Ba(IO₃)₂ · H₂O, Pb(ClO₃)₂ · H₂O, and Pb(BrO₃)₂ · H₂O The crystall structures of the isostructural halates Sr(BrO₃)₂ · H₂O, Ba(BrO₃)₂ · H₂O, Ba(IO₃)₂ · H₂O, Pb(ClO₃)₂ · H₂O, and Pb(BrO₃)₂ · H₂O were determined using X-ray single crystal data (monoclinic space group C2/c? C, Z = 4), The mean bond lengths and bond angles of the halate ions in the Ba(ClO₃)₂ · 1 H₂O-type compounds, which correspond to those of other halates, are Cl? O, 149.0, Br? O, 165.9, I? O, 180.2 pm, ClO₃^?, 106.4, BrO₃^?, 104.0, and IO₃^?, 99.6°. The structure data obtained are discussed in terms of possible orientational disorder of the water molecules, strengths of the hydrogen bonds, influence of the lead ions on the structure, and site group distortion of the halate ions.     

Die Kristallstrukturen von [Cu2Cl2(AA · H+)2](NO3)2 und [AA · H+]Pikr− (AA · H+ = Allylammonium; Pikr− = Pikrat)

The Crystal Structures of [Cu₂Cl₂(AA · H⁺)₂](NO₃)₂ and [AA · H⁺]Picr^? (AA · H⁺ = Allylammonium; Picr^? = Picrat) By an alternating current electro synthesis the crystal-line π-complex [Cu₂Cl₂(AA · H⁺)₂](NO₃)₂ has been obtained from CuCl₂ · 2H₂O, allylamine (AA), and HNO₃ in ethanolic solution. X-ray structure analysis revealed that the compound crystallized in the monoclinic system, space group P2₁/a, a = 7.229(3), b = 7.824(3), c = 26.098(6) Å, γ = 94.46(5)°, Z = 4, R = 0.025 for 2 023 reflections. The crystal structure is built up of Cu_nCl_n chains which are connected by π-bonding bidentate AA · H⁺ …? ON(O)O …? H⁺ · AA units. For comparision with the above complex the structure of [AA · H⁺]Picr^? (Picr^? = picrate anion) is also reported.     

Phase Chemistry Investigation on Cr(NO3)3‐Met‐H2O System

The solubility property of the ternary of Cr(NO₃)₃‐Met‐H₂O has been investigated in the whole concentration by the phase equilibrium method, and the phase diagram has been constructed. From the phase diagram, the congruently soluble complexes Cr(Met)(NO₃)₃·2H₂O (D) and Cr(Met)₂(NO₃)₃·2H₂O (E) have been prepared and characterized by chemical analysis, elemental analysis, IR and TG‐DTG. Their combustion energies have been determined by a RBC‐type I precision rotating‐bomb calorimeter, and their standard enthalpies of formation, Δf, Hθ_m, have been calculated as (‐1842.01 ± 2.13) kJ·mol^?1 and (‐1136.16 ± 4.45) kJ·mol^?1, respectively.     

Coordination Reaction of Alanine with Neodymium(III) and Erbium(III) Nitrate. Thermochemical study

The solid-state coordination reaction: Nd(NO₃)₃·6H₂O(s)+4Ala(s) → Nd(Ala)₄(NO₃)₃·H₂O(s)+5H₂O(_l) and Er(NO₃)₃·6H₂O(s)+4Ala(s) → Er(Ala)₄(NO₃)₃·H₂O(s)+5H₂O(l) have been studied by classical solution calorimetry. The molar dissolution enthalpies of the reactants and the products in 2 mol L^–1 HCl solvent of these two solid-solid coordination reactions have been measured using a calorimeter. From the results and other auxiliary quantities, the standard molar formation enthalpies of [Nd(Ala)₄(NO₃)₃·H₂O, s, 298.2 K] and[Er(Ala)₄(NO₃)₃·H₂O, s,298.2 K] at 298.2 K have been determined to be Δ_f H _m ⁰ [Nd(Ala)₄(NO₃)₃·H₂O,s, 298.2 K]=–3867.2 kJ mol^–1, and Δ_f H _m ⁰ [Er(Ala)₄(NO₃)₃·H₂O, s, 298.2 K]=–3821.5 kJ mol^–1. This revised version was published online in August 2006 with corrections to the Cover Date.     

Preparation and Thermal Chemical Property of Complexes of Zinc Nitrate with Trytophan

IntroductionZincisanessentialtraceelementtothelife .Manydiseasesarousedfromadeficiencyofzincelementhavere ceivedconsiderableattention .L α Aminoacidsarebasicunitsofproteins .L α Trytophanisoneoftheeightspeciesofaminoacidsindispensableforlife ,whichhastobeab sorbedfromfoodbecauseitcannotbesynthesizedinthehumanbody .InviewofthecomplexesofL α trytophanandessentialelementsasaddictiveswidelyusedinsuchfieldsasfoodstuff,medicineandcosmetic ,1 3theyhaveabroadenprospectforapplications .Briefly ,ab…     

Standard enthalpy of formation of metal (K,Ba, Li,Ca, Gd,Pb, Cu And Zn) salts of NTO

From measurements of the enthalpy of solution of metal salts of 3-nitro-1,2,4-triazol-5-one (NTO) in water, the standard enthalpies of formation of KNTO·H₂O, Ba(NTO)₂·3H₂O, LiNTO·2H₂O, Ca(NTO)₂·4H₂O and Gd(NTO)₃·7H₂O were determined as ?(676.9±2.6), ?(1627.0±2.5), ?(966.6.3±2.2), ?(1905.5±4.4) and ?(3020.1±6.4) kJ·mol^?1, respectively. From measurements of the enthalpy of precipitation of KNTO·H₂O crystal with Pb(NO₃)₂(aq), CuSO₄(aq) and Zn(NO₃)₂(aq), the standard enthalpies of formation of Pb(NTO)₂·H₂O, Cu(NTO)₂·2H₂O and Zn(NTO)₂·H₂O were determined as ?(247.4±5.9), ?(712.1±5.4) and ?(628.8±5.7) kJ·mol^?1, respectively.     

Determination of the acid dissociation constants of p-benzohydroquinone by the INDO method

The stepwise acid dissociation constants for p-benzohydroquinone (QH₂) in aqueous media have been explicitly calculated for the first time, with the INDO parametrized SCF –MO method. We have optimized the geometries of QH₂, QH^?, and Q^2? and of the QH₂ · 6H₂O, QH^? · (H₃O⁺) · 5H₂O, and Q^2? · (H₃O⁺)₂ · 4H₂O systems that model the solvated species. The presence of the associated water molecules (and hydronium ions) account for the stabilization due to hydrogen bonding as well as for a part of the effect of interaction of these molecules with the respective reaction fields in an aqueous medium. To simulate the first solvation shell in a more complete manner, four more water molecules have been considered to be placed above and below the quinonoid ring and the optimized geometries of the resulting hydrated species, QH₂ · 10H₂O, QH^? · (H₃O⁺) · 9H₂O, and QH^? · (H₃O⁺) · 8H₂O, have been determined. The standard free-energy changes calculated for the dissociation of QH₂ into QH^? and H⁺ is 0.0251 Hartree (65.9 kJ mol^?1) and that of QH^? into Q^2? and H⁺ is 0.0285 Hartree (74.8 kJ mol^?1). Experimentally observed dissociation constants for these two steps correspond to free-energy changes of 0.0214 Hartree (56.2 kJ mol^?1) and 0.0248 Hartree (65.1 kJ mol^?1), respectively. © 1995 John Wiley & Sons, Inc.     

Etude thermodynamique de la décomposition thermique des hydroxynitrates de zinc

The reaction scheme of thermal decomposition for four zinc hydroxynitrates was investigated by means of differential scanning calorimetry, thermogravimetry, mass spectrometry, and radiocrystallography. The thermal transformation of Zn(OH)(NO₃) · H₂O and of Zn₃(OH)₄(NO₃)₂ involves the formation of gaseous water and nitric acid from an actual chemical reaction. This reaction is not observed for Zn₅(OH)₈(NO₃)₂ · 2H₂O and Zn₅(OH)₈(NO₃)₂. These results show that the formation of gaseous nitric acid molecules inside the solids is specific to hydroxynitrates of divalent metals M, whose lamellar crystalline structure is characterized by a stacking of hexagonal close-packed layers of formula MX_2+m, where m = 0 or 1 and X = OH^?, H₂O, or NO^?₃.     

Synthesis and characterization of a new macrocyclic Schiff base derived from 2,6-diaminopyridine and 1,10-bis(2-formylphenyl)-1,4,7,10-tetraoxadecane and its Cu(II), Ni(II), Pb(II), Co(III) and La(III) complexes

A new macrocyclic ligand, 1,3,5-triaza-2,4:7,8:19,20-tribenzo-9,12,15,18-tetraoxacyclounkosa-1,5-diene (L) was synthesized by reaction of 2,6-diaminopyridine and 1,10-bis(2-formylphenyl)-1,4,7,10-tetraoxadecane. Then, its Cu^II, Ni^II, Pb^II, Co^III and La^III complexes were synthesized by the template effect by reaction of 2,6-diaminopyridine and 1,10-bis(2-formylphenyl)-1,4,7,10-tetraoxadecane and Cu(NO₃)₂· 3H₂O, Ni(NO₃)₂· 6H₂O, Pb(NO₃)₂, Co(NO₃)₂· 6H₂O, La(NO₃)₃·6H₂O respectively. The ligand and its metal complexes have been characterized by elemental analysis, IR, ¹H and ¹³C NMR, u.v–vis spectra, magnetic susceptibility, conductivity measurements and mass spectra. All complexes are diamagnetic and the Cu^II complex is binuclear. The Co^III complex was oxidized to Co^III.     

Complexes of Co(II), Ni(II), and Cu(II) with 4-(3,4-dichlorophenyl)-1,2,4-triazole

Novel oligonuclear complexes of Co(II), Ni(II), and Cu(II) with 4-(3,4-dichlorophenyl)-1,2,4-triazole (L) of the composition [M₃L₁₀(H₂O)₂](NO₃)₆ (M = Co(II), Ni(II)), [Ni₃L₆(H₂O)₆]Hal₆ (Hal = Cl^?, Br^?), and [Cu₅L₁₆(H₂O)₂](NO₃)₁₀ · 2H₂O were synthesized and studied by magnetic susceptibility, electronic and IR spectroscopy, and powder X-ray diffraction methods. All the above complexes are X-ray amorphous. Antifer-romagnetic exchange interactions between the M²⁺ ions were discovered in the [Co₃L₁₀(H₂O)₂](NO₃)₆ and [Ni₃L₁₀(H₂O)₂](NO₃)₆ complexes, whereas ferromagnetic exchange interactions were observed in the complexes [Ni₃L₆(H₂O)₆]Cl₆, [Ni₃L₆(H₂O)₆]Br₆, and [Cu₅L₁₆(H₂O)₂](NO₃)₁₀ · 2H₂O.     

Synthesis and spectral characterization of macrocyclic Schiff base by reaction of 2,6-diaminopyridine and 1,4- bis (2-carboxyaldehydephenoxy)butane and its CuII, NiII, PbII, CoIII and LaIII complexes

A new macrocyclic ligand, 1,3,5-triaza-2,4:7,8:15,16-tribenzo-9,15-dioxacycloheptadeca-1,5-diene (L) was synthesized by reaction of 2,6-diaminopyridine with 1,4-bis(2-carboxyaldehydephenoxy)butane. Then, its Cu^II, Ni^II, Pb^II, Co^III and La^III complexes were synthesized by the template effect by reaction of 2,6-diaminopyridine and 1,4-bis (2-carboxyaldehydephenoxy)butane and Cu(NO₃)₂ · 3H₂O, Ni(NO₃)₂ · 6H₂O, Pb(NO₃)₂, Co(NO₃)₂ · 6H₂O, La (NO₃)₃ · 6H₂O, respectively. The ligand and its metal complexes were characterized by elemental analysis, IR, ¹H- and ¹³C-n.m.r., UV-vis spectra, magnetic susceptibility, thermal gravimetric analysis, conductivity measurements and mass spectra. All complexes are diamagnetic and the Cu^II complex is binuclear. The Co^II complex was oxidised to Co^III.     

Synthesis,spectral, thermal,solid state d.c. electrical conductivity,fluorescence and biological studies of lanthanum(III) and thorium(IV) complexes of 24-membered macrocyclic triazoles

A series of La(III) and Th(IV) complexes have been synthesized by template condensation of 2,6-diformyl-4-methylphenol, bis-(4-amino-5-mercapto-1,2,4-triazol-3-yl)alkanes and La(NO₃)₃ ·?6H₂O/Th(NO₃)₄ ·?5H₂O in 2 : 2 : 1 molar ratio in ethanol. These complexes were characterized by elemental analyses, magnetic susceptibility, molar conductance, spectral (IR, UV–Vis, ¹H-NMR, FAB-mass), thermal, fluorescence and solid state d.c. electrical conductivity studies. The complexes are insoluble in water but soluble in DMF and DMSO. The observed molar conductance values indicate non electrolytes. Elemental analyses suggest 1 : 1 stoichiometry, [La(L^I–IV)(NO₃)(H₂O)₂] ·?3H₂O and [Th(L^I–IV)(NO₃)₂(H₂O)₂] ·?3H₂O. Spectroscopic studies indicate that coordination occurs through phenolic oxygen after deprotonation, nitrogen of azomethine group and bridging bidentate nitrates. The solid state d.c. electrical conductivity indicates semiconducting nature. All the Schiff bases and their La(III) and Th(IV) complexes were evaluated for biological properties; some compounds show promising results.     

Thiosulfatothiourea lead complexes

Interactions in the system Pb(NO₃)₂-Na₂S₂O₃-(NH₂)₂CS-H₂O were studied using UV spectroscopy. The results of the study indicate a possibility of complete substitution of thiourea for thiosulfate ions when the solution concentration is 10^?3 mol/L. The compounds PbS₂O₃ · (NH₂)₂CS · H₂O and PbS₂O₃ · 2(NH₂)₂CS · H₂O were isolated from concentrated aqueous solutions and characterized by IR spectroscopy and thermal analysis. The structure of these compounds is suggested. Thermolysis schemes for these compounds are suggested on the basis of the IR absorption spectra of thermolysis products.     

Synthesis and spectral studies of new macrocyclic Schiff base Cu(II), Ni(II), Cd(II), Zn(II), Pb(II), and La(III) complexes containing pyridine head unit

1,6-Bis(2-formylphenyl) hexane (I) was derived from 1,6-dibromohexane with salicylaldehyde and K₂CO₃ and the ligand (L) was derived from compound I and 2,6-diaminopyridine. Then, the Cu(II), Ni(II), Pb(II), Zn(II), Cd(II), and La(III) complexes with L were synthesized by the reaction of this ligand and Cu(NO₃)₂ · 3H₂O, Ni(NO₃)₂ · 6H₂O, Pb(NO₃)₂, Zn(NO₃)₂ · 6H₂O, Cd(NO₃)₂ · 6H₂O, and La(NO₃)₃ · 6H₂O, respectively. The ligand and its metal complexes were characterized by elemental analysis, IR, ¹H and ¹³C NMR, UV-Vis spectra, magnetic susceptibility, conductivity measurements, and mass spectra. All complexes are diamagnetic and the Cu(II) complex is binuclear. The article is published in the original.     

Bidentate coordination of a diketo phosphorus ylide: synthesis and structure of [(C6H5)3PC(COCH3)(COC6H5)-κO,O′]UO2(NO3)2

A 1?:?1 chelate complex [(C₆H₅)₃PC(COCH₃)(COC₆H₅)-κO,O′]UO₂(NO₃)₂ has been synthesized by reaction of (C₆H₅)₃PC(COCH₃)(COC₆H₅) with UO₂(NO₃)₂?·?6H₂O in methanol at room temperature and characterized by elemental analysis, spectroscopy as well as by single-crystal X-ray diffraction. The complex crystallizes in P2₁/n space group with a?=?10.007(2)?Å, b?=?15.285(7)?Å, c?=?19.20(1)?Å, β?=?91.22(3)°, V?=?2936(2)?ų, Z?=?4, D _c?=?1.847?g?cm^?3. In the solid state structure, the dihedral angle [88.1(4)°] between the planes defined by the two quartets of atoms O1 O8 O2 O4 and O6 O5 O3 O7 is close to 90°, as expected for a triangulated dodecahedral geometry around uranium.     

Coordination‐directed and Hydrogen‐bonded Assembly of Supramolecular Architectures Constructed from Diverse Coordination of Linear,Triangular, Tetragonal Pyramid,Trigonal Bipyramid,and Octahedral Mononuclear Units

Reaction of a imidazole phenol ligand 4‐(imidazlo‐1‐yl)phenol (L) with 3d metal salts afforded four complexes, namely, [Ni(L)₆] · (NO₃)₂ ( 1 ), [Cu(L)₄(H₂O)] · (NO₃)₂ · (H₂O)₅ ( 2 ), [Zn(L)₄(H₂O)] · (NO₃)₂ · (H₂O) ( 3 ), and [Ag₂(L)₄] · SO₄ ( 4 ). All complexes are composed of monomeric units with diverse coordination arrangements and corresponding anions. All the hydroxyl groups of monomeric cations are used as hydrogen‐bond donors to form O–H ··· O hydrogen bonds. However, the coordination habit of different metal ions produces various supramolecular structures. The Ni^II atom shows octahedral arrangement in 1 , featuring a 3D twofold inclined interpenetrated network through O–H ··· O hydrogen bond and π–π stacking interaction. The Cu^II atom of 2 displays square pyramidal environment. The O–H ··· O hydrogen bond from the [Cu(L)₄(H₂O)]²⁺ cation and lattice water molecule as well as π–π stacking produce one‐dimensional open channels. NO₃^– ions and lattice water molecules are located in the channels. 3 is a 3D supramolecular network, in which Zn^II has a trigonal bipyramid arrangement. Two different rings intertwined with each other are observed. The Ag^I in 4 has linear and triangular coordination arrangements. The mononuclear units are assembled into a 1D chain by hydrogen bonding interaction from coordination units and SO₄^2– anions.     

Tetranitratogoldsäure, (H5O2)[Au(NO3)4]·H2O: Synthese,Kristallstruktur und thermisches Verhalten des ersten sauren Nitrates des Goldes

Tetranitratogold(III) Acid, (H₅O₂)[Au(NO₃)₄]·H₂O: Synthesis, Crystal Structure, and Thermal Behaviour of the First Acidic Nitrate of Gold Yellow single crystals of (H₅O₂)[Au(NO₃)₄]·H₂O grow upon cooling of a solution of Au(OH)₃ in conc. nitric acid. The crystal structure contains (monoclinic, C2/c, Z = 4, a = 1214.5(2), b = 854.4(1), c = 1225.7(2) pm, β = 117.75(1)°, R_all = 0.0331) the Au³⁺ ion in coordination of four monodentate NO₃^— ligands. The [Au(NO₃)₄]^— units are linked by H₅O₂⁺‐ions. Significant hydrogen bonding is observed in the crystal structure between the H₅O₂⁺ ions and the H₂O molecules. The thermal analysis reveals a five step decomposition leading to elemental gold.     

Properties of A Phosphate Sensitive Solid State Electrode Based On Cerium-Iv-Hydrogenphosphate Mixed With Pvc

Abstract

The development of a phosphate sensitive electrode based on a heterogeneous (Ce-O-Ce) (HPO₄)₃·H₂O / PVC membrane is described. At a certain salt / PVC - mixture ratio an electrode for H₂PO₄ ^? with a slope of -50 mV/activity decade (AD) and a detection limit of approximately 20 ppm H₂PO₄ ^? is obtained. the selectivity coefficients for the interfering ions So₄ ^2?, cl^?, NO₃ ^?