The Thermal Decomposition of Fe(NO3)3·9H2O

Using thermogravimetric analyses as well as isothermal gravimetric measurements, the thermal stability of the iron(III) nitrate nanohydrate has been determined. Several decomposition stages are the result of melting, evaporation and hydrolysis processes occurring in the salt—water system in the temperature range of 20–400°C. Some of the intermediates and the final product (-Fe₂O₃) are characterized by means of chemical analyses, X-ray diffraction patterns and IR spectra.This revised version was published online in November 2005 with corrections to the Cover Date.     

Synthesis,Crystal Structure and Spectral Properties of [Ce(NO3)5(H2O)2]·2(Hphen)·(H2O)

A novel complex [Ce(NO3)5(H2O)2]·2(Hphen)·(H2O) (phen =1,10-phenanthroline) with formula C24H24CeN9O18 and Mr = 866.64 has been synthesized and structurally characterized by X-ray diffraction. It crystallizes in triclinic, space group Pī with a = 7.5534(2), b = 8.083(2), c = 25.8377(6) A, α = 86.847(1), β = 89.937(1), γ = 86.981(1)o, V = 1572.94(6) A3, Dc = 1.830 g/cm3, F(000) = 866, β = 1.545 cm-1 and Z = 2. The final refinement gave R = 0.0486 and wR = 0.1278 for 4852 observed reflections with I > 2σ(I). It consists of discrete [Ce(NO3)5(H2O)2]2- anion, two Hphen+ cations and a lattice water molecule. In the compound, all of the five nitrates are bidentate, and the coordination of Ce(III) is 12. The photo-luminescence of this compound was also investigated.     

Syntheses and structures of p-HOOCC6F4COOH · H2O (H2L · H2O) and luminescent coordination polymers [Tb2(H2O)4(L)3 · 2H2O] n and Tb2(Phen)2(L)3 · 2H2O

Compounds p-HOOCC₆F₄COOH · H₂O (H₂L · H₂O), [Tb₂(H₂O)₄(L)₃ · 2H₂O] _n (I), and Tb₂(Phen)₂(L)₃ · 2H₂O (II) are synthesized. According to the X-ray structure analysis data, the crystal structure of H₂L · H₂O is built of centrosymmetric molecules H₂L and molecules of water of crystallization. The crystal structure of compound I is built of layers of coordination 2D polymer [Tb₂(H₂O)₄(L)₃] _n and molecules of water of crystallization. The ligands are the L^2? anions performing both the tetradentate bridging and pentadentate bridging-chelating functions. The coordination polyhedron TbO₉ is a distorted three-capped trigonal prism. Acid H₂L manifests photoluminescence in the UV region (??_max = 368 nm). Compounds I and II have the green luminescence characteristic of the Tb³⁺ ions, and the band with ??_max = 545 nm (transition ⁵ D ₄?? ⁷ F ₅) is maximum in intensity. The photoluminescence intensity of compound II is higher than that for compound I.     

Synthesis, characterization and standard molar enthalpy of formation of Nd(C7H5O3)2·(C9H6NO)

The complex from reaction of neodymium chloride six-hydrate with salicylic acid and 8-hydroxyquinoline, Nd(C₇H₅O₃)₂·(C₉H₆NO), was synthesized and characterized by IR, elemental analysis, molar conductance, and thermogravimatric analysis. The standard molar enthalpies of solution of [NdCl₃·6H₂O(s)], [2C₇H₆O₃(s)], [C₉H₇NO(s)] and [Nd(C₇H₅O₃)₂·(C₉H₆NO)(s)] in a mixed solvent of anhydrous ethanol, dimethyl formamide (DMF) and perchloric acid were determined by calorimetry at 298.15 K. Based on Hess’ law, a new chemical cycle was designed, and the enthalpy change of the reaction

Structure and properties of tripyridine nitrosocomplexes of ruthenium: mer-[Ru(NO)Py3Cl(OH)]Cl·1.5H2O and mer-[Ru(NO)Py3Cl(H2O)]Cl2·2H2O·0.5HCl

The reaction of K₂[Ru(NO)Cl₅] with pyridine in aqueous ethanol at pH ～ 7–8 affords a nitrosoruthenium hydroxocomplex mer-[Ru(NO)Py₃Cl(OH)]Cl·1.5H₂O (I) (yield ～55%). Treatment of hydroxocomplex I with hydrochloric acid at room temperature gives the aqua complex mer-[Ru(NO)Py₃Cl(H₂O)]Cl₂·2H₂O·0.5HCl (II). The structures of the compounds are determined by X-ray crystallography: I, space group P2₁/n, a = 9.2292(4) Å, b = 11.7781(4) Å, c = 17.4915(7) Å, β = 90.9560(10)°, R = 4.84%; II, space group P-1, a = 7.3528(9) Å, b = 11.5793(11) Å, c = 13.6961(16) Å, α = 84.558(3)°, β = 87.668(4)°, γ = 74.146(4)°, R = 6.22%. Compounds I and II are characterized by powder XRD, ¹H and ¹³C NMR, and IR spectroscopy. The thermal decomposition of compound II in the inert atmosphere is examined by thermal analysis.     

Structural study of complex [Rh(NH3)5(NO2)](NO3)2·H2O, [Rh(NH3)5(NO2)][Pd(NO2)4], and K2[Rh(NH3)(NO2)5]·H2O salts

Compounds [Rh(NH₃)₅(NO₂)](NO₃)₂·H₂O (I) with a = 7.6230(3) Å, b = 7.6230(3) Å, c = 10.3584(4) Å, space group I-42m, Z = 2, d _calc = 2.026 g/cm³, V = 601.93(4) ų, Rh-NH_{3 eq} = 2.074 Å, Rh-NH_{3 ax} (NO₂) = 2.048 Å; [Rh(NH₃)₅(NO₂)][Pd(NO₂)₄] (II) with a = 8.095(3) Å, b = 22.422(8) Å, c = 7.887(3) Å, β = 98.559(17)°, space group Cc, Z = 4, d _calc = 2.461 g/cm³, V = 1415.6(9) ų, Rh-NH_{3 eq} = 2.069 Å, Rh-NH_{3 ax} = 2.090 Å, Rh-NO₂ = 2.002 Å; K₂[Rh(NH₃)(NO₂)₅]·H₂O (III) with a = 7.5177(5) Å, b = 20.9856(15) Å, c = 7.7017(5) Å, space group Cmc2₁, Z = 4, d _calc = 2.439 g/cm³, V = 1215.05(14) ų, Rh-NH_{3 ax} (NO₂) = 2.094 Å, Rh-NO_{2 eq} = 2.030 Å are synthesized and studied using single crystal X-ray diffraction.     

Synthesis and crystal structure of [La(NO3)3(H2O)2(BiPy)]·1.5(BiPy)

The molecular and crystal structure of the [La(NO₃)₃(H₂O)₂(2.2′-BiPy)]·1.5(2.2′-BiPy) compound is determined. The metal coordination polyhedron in the La(III) complex is formed from 10 donor atoms of O₈N₂: 6 oxygen atoms belong to three chelate-coordinated NO ₃ ^? anions, 2 oxygen atoms belong to two water molecules, and 2 nitrogen atoms belong to a bidentate bipyridine molecule coordinated in the neutral form. The structure is based on the metal complexes linked together in chains through the O(W)-H...O hydrogen bonds, in which oxygen atoms of the coordinated NO ₃ ^? anions act as acceptors. It is a framework structure, further stabilized by a system of O(W)-H...N and C-H...N hydrogen bonds, in which nitrogen atoms of the uncoordinated bipyridine molecules act as proton acceptors.     

Crystal,molecular, and electronic structure of carboxylate [Fe3O(CH3COO)6(H2O)3]NO3·4H2O

Results of X-ray structural analysis, IR spectroscopy, and quantum chemical study of the [Fe₃O(CH₃COO)₆(H₂O)₃]NO₃·4H₂O complex are reported. The crystal belongs to the monoclinic system with a=15.688(3), b=11.767(2), c=15.318(4) Å, γ=92.54(3)^o, space group P2₁/a, R=0.078. The molecule has a trinuclear structure: three iron atoms occupy the vertices of an equilateral, triangle with an Fe−Fe distance of 3.29 Å and are bonded by the μ₃-oxo and μ-CH₃COO⁻ (O,O′) ligands. To each iron atom, one water molecule is coordinated. Using the obtained values of populations on 3d AO of Fe (d _xy ^1.34 ; d _xz ^1.39 ; d _yz ^1.46 ; ; ) and charges on oxygen atoms (O _c ^−0.5 ; O _ac ^−0.31 ; O _w ^−0.31 ), we estimated the values of isomeric shift and quadrupole splitting (0.75 and 0.70 mm/sec, respectively; these are close to the experimental values of 0.75 and 0.58 mm/sec, (300 K)). Institute of Chemistry, Moldovian Academy of Sciences. Moldovian State University. Institute of Applied Physics, Moldovian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii., Vol. 35, No. 2, pp. 112–120, March–April, 1994. Translated by T. Yudanova     

Syntheses,crystal structures and antibacterial activities of [Cu2(C11H11NO5S)2(H2O)4] · 5H2O and [Ni2(C11H11NO5S)2(H2O)4] · 2H2O

The binuclear complexes [Cu₂L₂(H₂O)₄] · 5H₂O (1) and [Ni₂L₂(H₂O)₄] · 2H₂O (2) (where L = C₁₁H₁₁NO₅S, H ₂ L = 2-[(3-formyl-5-methyl-2-hydroxy-benzylidene)-amino]ethanesulfonic acid) have been synthesized and characterized by IR, elemental analysis and X-ray diffraction. The crystals belong to the monoclinic system, space group P2₁/c. Complex 1: a = 16.8902(12), b = 11.2829(6), c = 17.4249(11) Å; β = 106.709(4)°; S = 1.131; V = 3180.5(3) ų; Z = 4; D _Calcd = 1.729 g cm^?3; F(000) = 1712; μ = 1.554 mm^?1; R ₁ = 0.0519, wR ₂ = 0.1349; complex 2: a = 11.399(2), b = 19.985(3), c = 7.3694(10) Å; β = 108.664(7)°; S = 1.157; V = 1590.6(4) ų; Z = 2; D _Calcd = 1.604 g cm^?3; F(000) = 800; μ = 1.388 mm^?1; R ₁ = 0.1859, wR ₂ = 0.4346. The geometry around each metal(II) center can be described as slightly distorted octahedral. Water-sulfonic clusters and (H₂O)₄ water clusters can be observed for 1 from the crystal packing diagram, while cavity and offset face-to-face π–π stacking can be observed for 2. The complexes have been tested for the antibacterial activities which show antibacterial activities of 1 for β-hemolytic streptococcus, Staphylococcus aureus and Escherichia coli, and the antibacterial activity of 2 only for β-hemolytic streptococcus.     

Synthesis and Crystal Structure of Mn(phen)(CF3COO)(H2O)3·NO3

The mononuclear manganese complex Mn(phen)(CF3COO)(H2O)3(NO3 (C14H14O8N3F3Mn) has been synthesized, where phen = 1,10-phenanthroline. The molecular and crystal structures were determined by single-crystal X-ray diffraction. The crystal is of monoclinic, space group P21/c with a = 8.8550(3), b = 10.6529(3), c = 19.8763(2) A, β = 97.762(2)o, V = 1857.78(8) A3, Z = 4, Mr = 464.22, Dc = 1.660 g/cm3, μ = 0.789 mm-1, F(000) = 940, T = 293(2) K, R = 0.0764 and wR = 0.2441 for 1995 observed reflections with I > 2σ(I). In the crystal the manganese atom is six-coordinated by two chelated nitrogen atoms from phenanthroline, three oxygen atoms from water molecules and one oxygen atom from trifluoroacetate, completing an octahedral geometry.     

Synthesis,Structure and Characterization of Three Metal Molybdate Hydrates: Fe(H2O)2(MoO4)2·H3O,NaCo2(MoO4)2(H3O2)and Mn2(MoO4)3·2H3O

Three metal molybdate hydrates,Fe(H2O)2(MoO4)2·H3O(FeMo),NaCo2(MoO4)2(H3O2)(CoMo)and Mn2(MoO4)3·2H3O(MnMo),were synthesized by the mixed-solvent-thermal methods and characterized by singlecrystal X-ray...     

EPR study of gamma irradiated N-methyl taurine (C3H9NO3S) and sodium hydrogen sulphate monohydrate (NaHSO3·H2O) single crystals

EPR study of gamma irradiated C(3)H(9)NO(3)S and NaHSO(3).H(2)O single crystals have been carried out at room temperature. There is one site for the radicals in C(3)H(9)NO(3)S and two magnetically distinct sites for the radicals in NaHSO(3). The observed lines in the EPR spectra have been attributed to the species of SO(3)(-) and RH radicals for N-methyl taurine, and to the SO(3)(-) and OH radicals for sodium hydrogen sulfate monohydrate single crystals. The principal values of the g for SO(3)(-), the hyperfine values of RH and OH proton splitting have been calculated and discussed.     

[Co(Phen)2(H2O)2](HL)NO3·3H2O的合成及晶体结构

在水溶液中,以邻菲咯啉、丁二酸与硝酸钴为原料合成了一个新的超分子化合物[Co(Phen)2(H2O)2].(HL).(NO3).3H2O,并经元素分析、IR、X射线单晶衍射分析进行了结构表征.结构分析表明,晶体属三斜晶系,P1-空间群,a=0.968 0(2)nm,b=1.370(3)nm,c=1.394 9(3)nm,α=61.714(3)°,β=71.495(4)°,γ=79.575(4)°,V=1.543 7 nm3,Z=2,ρ=1.481 g/cm3,C28H31CoN5O12,Mr=688.51,F(000)=714 andμ=0.627 mm-1,7 754个独立衍射点中,5 428个可观察点满足I≥2σ(I),R1=0.074 5,wR2=0.210 7.晶体中[Co(Phen)2(H2O)2]2+通过π-π相互作用堆积成二维层状结构,层间通过氢键作用构成三维超分子.     

Thermochemical study of [Sm(C7H5O3)2·(C4H6NO2S)]·2H2O

The product from reaction of samarium chloride hexahydrate with salicylic acid and Thioproline, [Sm(C₇H₅O₃)₂·(C₄H₆NO₂S)]·2H₂O, was synthesized and characterized by IR, elemental analysis, molar conductance, and thermogravimetric analysis. The standard molar enthalpies of solution of [SmCl₃·6H₂O(s)], [2C₇H₆O₃(s)], [C₄H₇NO₂S(s)] and [Sm(C₇H₅O₃)₂·(C₄H₇NO₂S)·H₂O(s)] in a mixed solvent of absolute ethyl alcohol, dimethyl sulfoxide(DMSO) and 3 mol L^?1 HCl were determined by calorimetry to be Δ_s H _m ^Φ [SmCl₃ δ6H₂O (s), 298.15 K]= ?46.68±0.15 kJ mol^?1 Δ_s H _m ^Φ [2C₇H₆O₃ (s), 298.15 K]= 25.19±0.02 kJ mol^?1, Δ_s H _m ^Φ [C₄H₇NO₂S (s), 298.15 K]=16.20±0.17 kJ mol^?1 and Δ_s H _m ^Φ [Sm(C₇H₅O₃)₂·(C₄H₆NO₂S)]·2H₂O (s), 298.15 K]= ?81.24±0.67 kJ mol^?1. The enthalpy change of the reaction (1) $$ SmCl_3 \cdot 6H_2 O(s) + 2C_7 H_6 O_3 (s) + C_4 H_7 NO_2 S(s) = Sm(C_7 H_5 O_3 )_2 \cdot (C_4 H_6 NO_2 S) \cdot 2H_2 O(s) + 3HCl(g) + 4H_2 O(1) $$ was determined to be Δ_s H _m ^Φ =123.45±0.71 kJ mol^?1. From date in the literature, through Hess’ law, the standard molar enthalpy of formation of Sm(C₇H₅O₃)₂(C₄H₆NO₂S)δ2H₂O(s) was estimated to be Δ_s H _m ^Φ [Sm(C₇H₅O₃)₂·(C₄H₆NO₂S)]·2H₂O(s), 298.15 K]= ?2912.03±3.10 kJ mol^?1.     

Structure of (C3H5NH3)2H2P2O7·H2O

The bis(cyclopropylammonium)dihydrogenodiphosphate monohydrate is a new diphosphate associated with the organic molecule C₃H₅NH₂. We report the chemical preparation and the crystal structure of this organic cation diphosphate. (C₃H₅NH₃)₂H₂P₂O₇.H₂O is orthorhombic (S.G. : P2₁2₁2₁), with Z = 4 and the following unit-cell parameters : a = 4.828(1) Å, b = 11.011(1) Å, c = 25.645(2) Å. The P₂O₇ groups and H₂O water molecules form a succession of bidimensional layers perpendicular to the c axis. The organic cations ensure the three-dimensional cohesion by NH-O hydrogen bonds.     

Synthesis and properties of tetraalkylammonium chlorides peroxosolvates (CH3)4NCI·H2O2 and (C2H5)4NCl·H2O2

Tetraalkylammonium chlorides peroxosolvates (CH₃)₄NCl·H₂O₂ and (C₂H₅)₄NCl·H₂O₂ were synthesized. The composition of the solvates was proved by chemical analysis; their X-ray patterns, IR spectra, and thermograms were obtained. The solubility of the solvates in water and their stability in aqueous solutions were investigated.     

Crystal structures of Co3(SeO3)3·H2O and Ni3(SeO3)3·H2O,two new isotypic compounds

Summary The crystal structures of the new, hydrothermally synthesized, isotypic compounds Co₃(SeO₃)₃·H₂O and Ni₃(SeO₃)₃·H₂O were determined by direct and Fourier methods and refined toR _w=0.023, 0.032 using single crystal X-ray data up to sin/=0.81 Å^–1 [space group P ,a=8.102 (2), 7.986 (3) Å;b=8.219 (2), 8.133 (3) Å;c=8.572 (2), 8.422 (3) Å, =69.15 (1), 69.50 (1)°; =62.88 (1), 62.50 (1)°; =67.23 (1), 67.64 (1)°;Z=2]. The structures are built up from [Me ₅(SeO₃)₆·2H₂O]^2– sheets containing three crystallographically different types of octahedrally coordinatedMe ²⁺ and trigonal pyramidal coordinated Se⁴⁺ atoms, respectively. These sheets are linked only by a fourth type ofMe ^2+[6] atom. All coordination polyhedra deviate significantly from their ideal shapes, bond lengths within the extremly distortedMe(4)O₆ polyhedra range from 1.983 (2) Å to 2.403 (2) Å in Co₃(SeO₃)₃·H₂O and from 1.987 (4) Å to 2.301 (3) Å in the Ni compound, O-Se-O bond angles were found between 92.8 (2)° and 104.9 (1)°. Hydrogen bond lengths are 2.802 (3)Å and 2.600 (4)Å in the Co compound, and 2.762 (6) Å and 2.561 (6) Å in Ni₃(SeO₃)₃·H₂O. The latter is one of the shortest known hydrogen bonds donated by a water molecule.

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Die Kristallstrukturen von Co₃(SeO₃)₃·H₂O und Ni₃(SeO₃)₃·H₂O, zwei neue isotype Verbindungen

Zusammenfassung Die Kristallstrukturen der neuen, hydrothermal synthetisierten, isotypen Verbindungen Co₃(SeO₃)₃·H₂O und Ni₃(SeO₃)₃·H₂O wurden mit direkten und Fourier-Methoden bestimmt und unter Verwendung von Einkristallröntgendaten bis sin/=0.81 Å^–1 aufR _w-Werte von 0.023, 0.032 verfeinert [Raumgruppe P ,a=8.102 (2), 7.986 (3) Å;b=8.219 (2), 8.133 (3) Å;c=8.572 (2), 8.422 (3) Å, =69.15 (1), 69.50 (1)°; =62.88 (1), 62.50 (1)°; =67.23 (1), 67.64 (1)°;Z=2]. Die Strukturen werden von [Me ₅(SeO₃)₆·2H₂O]^2– Schichten aufgebaut, die je drei kristallographisch unterschiedliche Arten von oktaedrisch koordiniertenMe ²⁺ und trigonal pyramidal koordinierten Se⁴⁺ Atomen enthalten. Diese Schichten sind nur durch eine vierte Art vonMe ^2+[6] Atomen verknüpft. Alle Koordinationspolyeder weichen deutlich von ihren Idealformen ab, Bindungslängen in den extrem verzerrtenMe(4)O₆ Polyedern variieren zwischen 1.983 (2) Å und 2.403 (2) Å in Co₃(SeO₃)₃·H₂O und zwischen 1.987 (4) Å und 2.301 (3) Å in der Ni-Verbindung, O-Se-O-Bindungswinkel liegen zwischen 92.8 (2)° und 104.9 (1)°. Wasserstoffbrückenlängen sind 2.802 (3) Å und 2.600 (4) Å in der Co-Verbindung, und 2.762 (6) Å und 2.561 (6) Å in Ni₃(SeO₃)₃·H₂O. Letztere ist eine der kürzesten bekannten Wasserstoffbrücken eines Wassermoleküls.

     

Structural,spectral and potentiometric characterization,and antimicrobial activity studies of [Zn(phen)2(cnge)(H2O)](NO3)2 · H2O

An octahedral Zn complex with o-phenanthroline (o-phen) and cyanoguanidine (cnge) has been synthesized and characterized. The crystal structural data show the formation of a ZnN₅O core where the metal coordinates to two mutually perpendicular o-phenanthrolines as bidentate ligands [Zn–N bond lengths in the 2.124(2)–2.193(2)?Å range], the cyanide nitrogen of a cnge [d(Zn–N)?=?2.092(2)?Å, ∠(Zn–N–C)?=?161.1(2)°], and a water molecule [d(Zn–Ow)?=?2.112(2)?Å]. Spectral data (FT-IR, Raman, and fluorescence) and speciation studies are in agreement with the structure found in the solid state and the one proposed to exist in the solution. To evaluate the changes in the microbiological activity of Zn, antibacterial studies were carried out by observing the changes in minimum inhibitory concentration of the complex, the ligands, and the metal against five different bacterial strains. The antibacterial activity of Zn improved upon complexation in three of the tested strains.     

Synthesis and structure of [Cr3O(CH3COO)6(H2O)3][UO2 (CH3COO)3] · 3H2O

Crystals of [Cr₃O(CH₃COO)₆(H₂O)₃][UO₂(CH₃COO)₃]·3H₂O (I) were synthesized for the first time and studied by X-ray crystallography. The crystals of I are orthorhombic: a = 8.3561(3) ?, b = 16.8421(5) ?, c = 25.7448(9) ?, V = 3623.2(2) ?³, space group P2₁2₁2₁, Z = 4, R = 0.0409. The structure is composed of trinuclear [Cr₃O(CH₃COO)₆(H₂O)₃]⁺ complexes and mononuclear [UO₂(CH₃COO)₃]^? complexes classified with crystal-chemical groups A₃M³B ₆ ² M ₃ ¹ (A = Cr³⁺, M³ = O^2?, B² = CH₃COO^?, M¹ = H₂O) and AB ₃ ⁰¹ (A = UO ₂ ²⁺ , B⁰¹ = CH₃COO^?), respectively. The complexes are bound to each other by electrostatic interactions and hydrogen bonds involving outer-sphere water molecules. The results of IR spectroscopic study of I are in good agreement with the structural data for the crystal.