Synthesis and characterization of a new iron (II)— dinitrogen compound with PDTA as ligand

A new dinitrogen complex of formula Na₂[Fe(PDTA) (N₂] (H₂O)₂ has been synthesized in aqueous solution from [Fe(H-PDTA) (H₂O)], 3/2H₂O and NaN₃. The complex has been characterized by chemical analysis, IR and electronic spectra, and magnetic measurements. The thermal decomposition process has been studied by using DTA and TG techniques. The evolution of gases was followed by Gas Chromatography.     

Studies of thermal decomposition of hydrazidocarbonates of some first row transition elements

The thermal properties of some hydrazidocarbonates of copper, Cu(N₂H₃COO)₂.0.5H₂O, nickel, Ni(N₂H₃COO)₂.2N₂H₄, and iron, Fe(N₂H₃COO)₂ and N₂H5[Fe(N₂H₃COO)₃].H₂O, were studied in an inert argon atmosphere. The TG, DTG and DSC curves for these compounds were taken. In the case of N₂H₅[Fe(N₂H₃COO)₃].H₂O, intermediates were observed and isolated during the decomposition. The end-products were metal powders oxidized to a greater or lesser degree.

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Zusammenfassung In einer inerten Argonatmosphäre wurden die thermischen Eigenschaften einiger Hydrazidocarbonate von Kupfer, Cu(N₂H₃COO)₂.0.5H₂O, Nickel Ni(N₂H₃COO)₂.2N₂H₄ und Eisen Fe(N₂H₃COO)₂ bzw. N₂H₅[Fe(N₂H₃COO)₃].H₂O ermittelt, d.h. TG-, DTG- und DSC-Kurven wurden angefertigt. Im Falle von N₂H₅[Fe(N₂H₃COO)₃].H₂O konnten während der Zersetzung auch Zwischenprodukte beobachtet und isoliert werden. Die Endprodukte waren mehr oder weniger oxydierte Metallpulver.

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Paper presented at the 6th World Conference for Thermal Analysis, Capri, 1989.

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This work was supported by the Research Council of Slovenia.     

Hydrazinium metal(II) and metal(III) ethylenediamine tetraacetate hydrates

Hydrazinium metal ethylenediaminetetraacetate complexes of molecular formula (N₂H₅)₂[Mg(edta)·H₂O], (N₂H₅)₃[Mn(edta)··H₂O](NO₃)·H₂O, N₂H₅[Fe(edta)·H₂O], N₂H₅[Cu(Hedta)·H₂O] and N₂H₅[Cd(Hedta)·H₂O]·H₂O have been synthesized and characterized by elemental and chemical analysis, conductivity and magnetic measurements and spectroscopic techniques. The thermal behaviour of these complexes has been studied by thermogravimetry and differential thermal analysis. The data set provided by the simultaneous TG-DTA curves of the complexes shows the occurrence of three or four consecutive steps such as dehydration, ligand pyrolysis and formation of metal oxides. X-ray powder diffraction patterns of copper and cadmium complexes show that they are not isomorphous. These studies suggest seven coordination for Mg,Mn, Fe complexes and six coordination for Cu and Cd derivatives.     

Hydrate isomerism in [Cu(en)2(H2O)1.935]2[Fe(CN)6]·4H2O

The title compound, bis[di­aqua­bis­(ethyl­enedi­amine‐κ²N,N′)copper(II)­] hexa­cyano­iron(II) tetrahydrate, [Cu(C₂H₈N₂)₂(H₂O)_1.935]₂[Fe(CN)₆]·4H₂O, was crystallized from an aqueous reaction mixture initially containing CuSO₄, K₃[Fe(CN)₆] and ethyl­enedi­amine (en) in a 3:2:6 molar ratio. Its structure is ionic and is built up of two crystallographically different cations, viz. [Cu(en)₂(H₂O)₂]²⁺ and [Cu(en)₂(H₂O)_1.87]²⁺, there being a deficiency of aqua ligands in the latter, [Fe(CN)₆]⁴⁻ anions and disordered solvent water mol­ecules. All the metal atoms lie on centres of inversion. The Cu atom is octahedrally coordinated by two chelate‐bonded en mol­ecules [mean Cu—N = 2.016 (2) Å] in the equatorial plane, and by axial aqua ligands, showing very long distances due to the Jahn–Teller effect [mean Cu—O = 2.611 (2) Å]. In one of the cations, significant underoccupation of the O‐atom site is observed, correlated with the appearance of a non‐coordinated water mol­ecule. This is interpreted as the partial contribution of a hydrate isomer. The [Fe(CN)₆]⁴⁻ anions form quite regular octahedra, with a mean Fe—C distance of 1.913 (2) Å. The dominant intermolecular interactions are cation–anion O—H⋯N hydrogen bonds and these inter­actions form layers parallel to (001).     

Complex Compounds of Ga(III) and In(III) with Catechol

The identification of various species present in aqueous solutions of M(III)-Catechol system [M(III) = Ga(III) or In(III)] has been made through conductometric and electrometric studies. With a view to confirm the results suggested by physico-chemical methods, several hexa coordinated complexes of the type K[M(R) (H₂O)₂ (OH)₂]. × H₂O, K₂[M(R)₂(H₂O) (OH)]. × H₂O, K₃[M(R)₃]. × H₂O (M = Ga(III), In(III)R = C₆H₄O₂^?) have been isolated.     

Synthesis of Hafnium(IV) Polyaminoacetates

The interaction of hafnium(IV) salts (oxide-dichloride, chloride, and bromide) with nitrilotriacetic acid (NTA), diethylenetriamminepentaacetic acid (DTPA), 1,2-diaminocyclohexanetetraacetic acid (CDTA), 1,3-dipropylmino-2-hydroxy N,N,N′,N′-tetraacetic acid (dpta), and N-(2-hydroxyethyl)ethylenediamine triacetic acid (HEDTA) has been studied. The corresponding complexes Na₂[Hf(NTA)₂]·3H₂O (1), Na[HfDTPA]·3H₂O (2), [HfCDTA(H₂O)₂] (3), and Na[Hf₂(dpta)₂]·7.5H₂O·0.5C₂H₅OH (4) have been isolated and characterized and their structures have been determined by single crystal X-ray diffraction. Biological studies of [HfCDTA(H₂O)₂] have shown that in 5% glucose solution this complex has low toxicity and good contrasting ability.     

A new dinitrogen compound of ruthenium(II) with propylenediaminetetraacetic acid

Summary A new dinitrogen complex of formula Na₂[Ru(PDTA)(N₂)] · 2H₂O has been synthesized in aqueous solution from [Ru(HPDTA) (H₂O)] · H₂O and NaN₃. The complex has been characterized by chemical analysis, infrared and electronic spectra, and magnetic measurements. The thermal decomposition process has been studied using DTA and TG techniques. The evolution of gases was followed by gas chromatography.     

The Sodium (Iso)Cyanurates Nax[H3–xC3N3O3]·yH2O (x = 1–3, y = 0, 1): A Key‐Series for Understanding the Crystal Chemistry of Metal (Iso)Cyanurates

The (iso)cyanurates Na[H₂C₃N₃O₃] · H₂O, Na₂[HC₃N₃O₃] · H₂O, Na₂[HC₃N₃O₃], and Na₃[C₃N₃O₃] were synthesized phase pure from Na₂CO₃ · 10H₂O, NaOH, and cyanuric acid, respectively, in aqueous solution by carefully adjusting the crystallization conditions. The crystal structures of all compounds were determined by single‐crystal X‐ray diffraction {Na₂[HC₃N₃O₃] · H₂O: P1 , a = 3.51660(10) Å, b = 7.8300(3) Å, c = 11.3966(4) Å, α = 86.4400(10)°, β = 85.5350(10)°, γ = 85.0720(10)°, Z = 2, R₁ = 0.030, wR₂ = 0.078; Na₂[HC₃N₃O₃]: Pnma, a = 6.3409(6) Å, b = 12.2382(13) Å, c = 6.5919(7) Å, Z = 4, R₁ = 0.045, wR₂ = 0.079; Na₃[C₃N₃O₃]: R3 c, a = 11.7459(3) Å, c = 6.5286(3) Å, Z = 3, R₁ = 0.039, wR₂ = 0.066}. The structures show ribbons (Na[H₂C₃N₃O₃] · H₂O), dimers (Na₂[HC₃N₃O₃] · H₂O), chains (Na₂[HC₃N₃O₃]), or columns (Na₃[C₃N₃O₃]) of hydrogen‐bonded and parallel stacked (iso)cyanurate anions. These motifs are shown to be characteristic for certain degrees of protonation and hydration, and all (iso)cyanurate crystal structures found so far were classified accordingly. X‐ray powder patterns, thermogravimetry curves, IR and UV/Vis spectra were measured for all compounds.     

Investigation of K-edge absorption spectra of vanadium coordination compounds

High resolution vanadium K-edge spectra (XANES) have been measured using the synchrotron radiation available at the Institute of Nuclear Physics of the Academy of Sciences of the U.S.S.R., Novosibirsk. The compounds investigated include anions of oxalic acid (ox), ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA) as ligands: (NH₄)₃[VO₂(ox)₂]·2H₂O, (NH₄)₂ [VO(ox)₂H₂O]·H₂O, Na₃[VO₂(EDTA)]·9H₂O, Na₂[VO(EDTA)]·3H₂O, Na[V(EDTA)]·3H₂O, Na₃[V₂O₃(NTA)₂]·6H₂O, Ba[VO(NTA)H₂O]₂·2H₂O and Na₃[V(NTA)₂]. The vanadium oxidation states in these compounds cover the region between +5 and +3. The object of this investigation is to obtain further information about the effect of bonding and coordination geometry on the details of the absorption spectra, especially on the intensity and position of a well defined pre-edge absorption peak in most of the compounds.     

Synthese und Kristallstruktur von [Na3(H2O)6,5(EtOH)][PhSnS3] · 3 EtOH

Synthesis and Crystal Structure of [Na₃(H₂O)_6,5(EtOH)][PhSnS₃] · 3 EtOH Ph₄Sn₄S₆ reacts with Na₂S · 5 H₂O in aqueous acetone to form Na₃[PhSnS₃]. Recrystallization of the crude product from ethanol leads to colourless needles of [Na₃(H₂O)_6,5(EtOH)][PhSnS₃] · 3 EtOH 1 . The crystal structure of 1 was determined by X-ray diffraction. 1 consists of [PhSnS₃]^3– anions and sodium cations which are coordinated by water, ethanol and sulfur atoms of the [PhSnS₃]^3– anions. The [PhSnS₃]^3– anion contains a tin atom which is coordinated nearly tetrahedrally by a phenyl group and three sulfur atoms. The Sn–S bonds are 237,4(2)–238,4(2) pm.     

Pentacyanido(L)ferrate(III) complexes: Crystal structures, electrochemical and DFT studies (L = pyrazine, 4,4′-bipyridine, azide)

The crystal structures of two pentacyanido(L) ferrate(III) complexes, [P(C₆H₅)₄]₂[Fe(CN)₅(prz)]·4H₂O 1, [P(C₆H₅)₄]₂[Fe(CN)₅(4,4′-bipy)]·3H₂O 2, have been solved. Within the two complex anions the iron atoms are hexacoordinated by five cyanido ligands, the sixth position being occupied by the nitrogen atom arising from pyrazine and, respectively, 4,4′-bipyridine. The electrochemical properties of compounds 1, 2 and of the azido derivative, (Ph₄As)₂[Na(H₂O)₄][Fe(CN)₅(N₃)] 3, have been investigated by cyclic voltammetry. A relatively complicated redox behavior of these complexes was found, due especially to the electron transfer involving the central metallic ion that changes reversibly its oxidation state (Fe^III/Fe^II redox site) and also to the coligand (4,4′-bipyridine, pyrazine or azide) which intervenes in a distinct electron transfer. The experimental data have been rationalized through DFT calculations.     

Mössbauer Studies of Radiation Effect on Pentacyano Complexes of Iron

Mössbauer and ir spectroscopies have been applied to the study of radiation effect on Fe¹¹X(CN)₃ (X=NO⁺, NH₃, H₂O, NO₂^?, SO₃⁼) and Fe¹¹¹X(CN)₃ (X=NH₁, H₂O, NO₂^?). Fe(II) complexes were not oxidized to Fe(III), whereas Fe(III) complexes were reduced to Fe(II). Na₂[FeNH₃(CN)₃]·H₂O was partially reduced at 7 hour irradiation, but [FeNO(CN)₂]⁼ was obtained at the longer irradiations due to the replacement of H by O produced by water radiolysis.     

Chemistry of iron complexes—III. X-ray diffraction,ESR and other spectral studies of new iron(II) and iron(III) complexes with tri-p-tolylarsine oxide

Reactions of iron(II) and iron(III) salts with tri-p-tolylarsine oxide(L) in suitable organic solvents yield complexes of formulas: (i) [FeL₂Cl₂(OH₂)₂] [FeCl₄].2H₂O, [FeL₂Br₂] [FeBr₄].2H₂O; (ii) [Fe(NCS)₃L₂].H₂O; (iii) [FeL(O₂ClO₂)₂(OH₂)] (ClO₄).0.25C₆H₆; (iv) [FeL₃I] [FeI₃].H₂O and (v) [Fe(CO)₃LI]I. Characterization has been done through elemental analyses, IR, far IR, ESR, and reflectance spectra, molar conductance, magnetic moments, t.g.a. and X-ray diffraction (powder) data. The species [FeL₂Cl₂(OH₂)₂]⁺, [FeL₂Br₂]⁺, [Fe(NCS)₃L₂], [FeL(O₂ClO₂)₂OH₂]⁺, [FeL₃I]⁺ and [Fe(CO)₃LI]⁺ have been assigned trans-octahedral, trans-square planar, trans-trigonal bipyramid, trans-octahedral, tetrahedral and cis-trigonal bipyramid structures respectively.     

The Fe2+ chelate of hydrazinecarboxylic acid studied by the Mössbauer effect

The chelate compounds K[Fe(hyc)₃] and N₂H₅[Fe(hyc)₃]·H₂O (hyc = N₂H₃COO) were studied by the Mössbauer effect of ⁵⁷Fe at various temperatures. At room temperature the quadrupole splitting parameter is 2.77 mm/sec for K[Fe(hyc)₃] and 2.35 mm/sec for N₂H₅[Fe(hyc)₃]·H₂O, and the center shift is 1.08 mm/sec for both compounds. The temperature dependences of the quadrupole parameters yielded the crystal field splittings of the ⁵T_2g levels of the Fe²⁺ ions which indicate large trigonal distortion of the Fe(hyc)₃ anion. Using a molecular crystal-like treatment of the ferrous ion vibrations the temperature dependence of the recoilless fraction gave an effective Debye temperature Θ_D = 71°K for K[Fe(hyc)₃] and Θ_D = 90°K for N₂H₅[Fe(hyc)₃]·H₂O. No evidence for magnetic ordering was found down to 4.5°K in either compound.     

3d-Metal Nitroprusside–Thiosemicarbazide Complexes: Synthesis and Properties

The following complexes were synthesized from 3d-metal nitroprussides and thiosemicarbazide: [CrL₃][Fe(CN)₅H₂O] · 6H₂O, [FeL₃]₂[Fe(CN)₅NO]₃ · 14H₂O, [CoL₃]₂[Fe(CN)₅NO]₃ · 4H₂O, [NiL₂][Fe(CN)₅NO], [CuL₂][Fe(CN)₅NO] · 5H₂O, and [[ZnL₂][Fe(CN)₅NO], where L is thiosemicarbazide. Their structures and properties were studied by IR and diffuse reflection spectroscopies and DTA.     

Structure and magnetic properties of binuclear [Cu(amppz)(μ-NC)Fe(CN)4NO] (amppz = 1,4-bis(3-aminopropyl)piperazine)

The heterobimetallic compound [Cu(amppz)(μ-NC)Fe(CN)₄NO] (amppz = 1,4-bis(3-aminopropyl)piperazine) has been prepared by the reaction of [Cu(amppz)(ClO₄)]ClO₄ and Na₂[Fe(CN)₅NO]?2H₂O in aqueous solution and was characterized by IR spectroscopy, magnetic measurement, and X-ray single-crystal diffraction. The neutral complex has a cyanide-bridged binuclear structure in which the iron(II) is six-coordinate by five carbons from cyano groups (one of them forms a bridge) and one nitrogen from nitrosyl in an octahedral arrangement, whereas the copper(II) is five-coordinate by four amppz-nitrogens and one cyanide-nitrogen in a distorted square-pyramidal geometry. Magnetic investigation revealed a weak antiferromagnetic intermolecular interaction between the copper(II) ions with T_N = 6 K.     

Synthesis of Isotope Enriched (CN3H6)2[57Fe(CN)5NO] starting from 57Fe

A high‐yield, mmolar‐scale synthesis of pure guanidinium nitroprusside, (CN₃H₆)₂[⁽⁵⁷⁾Fe(CN)₅NO] (GNP) from iron metal is described. The iron metal contained pieces of 95.3% ⁵⁷Fe together with normal iron so that an isotope enrichment in ⁵⁷Fe of 25% was achieved. Single‐crystals of GNP could be grown in cubic shape and dimensions of about 3 × 4 × 4 mm³. The purity of the GNP product and the intermediates K₄[⁽⁵⁷⁾Fe(CN)₆] · 3 H₂O and Na₂[⁽⁵⁷⁾Fe(CN)₅NO] · 2 H₂O was ascertained by ⁵⁷Fe Mössbauer spectroscopy as well as ¹³C, ¹⁴N and ⁵⁷Fe NMR spectroscopy. The ⁵⁷Fe NMR chemical shift for [⁽⁵⁷⁾Fe(CN)₅NO]^2– in GNP was detected at +2004.0 ppm [vs Fe(CO)₅].     

Transition metal ion complexes of thiosemicarbazones derived from 2-acetylpyridine. Part 5. The4 N-cyclohexyl derivative

Summary Metal ion complexes of the thiosemicarbazone,⁴ N-cyclohexyl-2-[1-(2-pyridinyl)ethylidene]hydrazinecarbothioamide (HL4CH), have been prepared and spectrally characterised. Both the size of the cyclohexyl-group attached at⁴N as well as the⁴N hydrogen affect the stoichiometry and stereochemistry of the isolated complexes. The large cyclohexyl-group evidently causes the isolation of [Fe(HL4CH) (L4CH)H₂O](ClO₄) instead of the expected [Fe(L4CH)₂]ClO₄[Co(L4CH)Br] instead of [Co(HL4CH)Br₂], and [Ni(L4CH)Br] instead of [Ni(HL4CH)₂Br₂]. The presence of the hydrogen at⁴N presumably hinders the deprotonation of HL4CH on complex formation since [Cu(HL4CH)Cl₂] was isolated rather than [CuLCl], which occurs when the thiosemicarbazone has⁴N with two alkyl groups or incorporated in a ring. Further, although we prepared [Ni(L4CH)Br], complexes of this stoichiometry are planar and diamagnetle when⁴N does not have a hydrogen(s) attached to it rather than tetrahedral and paramagnetic as has been found for the present complex.     

Anionic Diversity in Iodobismuthate Chemistry

Three salts containing different iodobismuthate anions have been synthesized. [(CH₃)₂NH₂]₃[BiI₆] was prepared by oxidation of bismuth by iodine in N,N‐dimethylformamide. [(CH₃)₂NH₂]₃[BiI₆] crystallizes in the space group with a = 30.760(3) Å and c = 8.8039(5) Å and contains monomeric [BiI₆]^3? anions. The hydrate Na₄[Bi₂I₁₀] · 14H₂O was prepared by the oxidation of bismuth using iodine in acetonitrile in the presence of NaI. Na₄[Bi₂I₁₀] · 14H₂O crystallizes in the space group C2/m with a = 12.875(2) Å, b = 16.177(2) Å, c = 9.904(2) Å and β = 106.57(6)°. The structure contains dimeric [Bi₂I₁₀]^4? anions and rows of sodium ions, with bridging water molecules. The hydrate [Na{(CH₃)₂NCHO}₂(H₂O)]₃[Bi₂I₉] was prepared by dissolution of Na₄[Bi₂I₁₀] · 14H₂O in N,N‐dimethylformamide and crystallizes in the space group with a = 13.2309(13) Å, b = 13.3791(14) Å, c = 18.722(2) Å, α = 70.338(9)°, β = 72.651(9)° and γ = 62.183(5). The structure contains dimeric [Bi₂I₉]^3? anions and cationic polymers, equation/tex2gif-stack-1.gif[Na{(CH₃)₂NCHO}₂(H₂O)]⁺.     

Polyol-Metall-Komplexe. 17. Kristalline Eisen(III)-Komplexe mit zweifach deprotonierten Anhydroerythrit-Liganden

Polyol Metal Complexes. 17. Crystalline Iron(III) Complexes with Twofold Deprotonated Anhydroerythritol Ligands Three new crystalline ferrates(III) with diolato ligands derived from anhydroerythritol by deprotonation have been synthesized from wet alcoholic and from aqueous solution. Almost colourless, monoclinic crystals of Na₂[Fe(AnEryt-H_-2)₂(OH)] · 0.5 NaNO₃ · 3.5 H₂O ( 1 ) have been prepared from ethanolic solutions. They content mononuclear bis diolato hydroxo ferrate(III) dianions. Trinuclear hexakis diolato μ₃-methoxo triferrat(III) tetraanions constitute the anionic part of Na₄[Fe₃(AnErytH_-2)₆(OMe)] · 2.5 NaNO₃ ( 2 ), yellow-green hexagonal crystals of which are formed from wet methanolic solutions. Yellow-green triclinic crystals of Ba₂[Fe₂(AnEryt-H_-2)₄(μ-OH)₂] · 12 H₂O ( 3 ) have been precipitated from aqueous solutions. In 3 , the anions of 1 are dimerized to give tetrakis diolato di-μ-hydroxo diferrat(III) tetraanions.