Pivalate Bridged High Spin Manganese(II) and Iron(II) Polymers

Antiferromagnetic Mn(II) polymers of general formula {[L₂Mn(μ-OOCCMe₃)₂][Mn₂(μ-OOCCMe₃)₄]}_n (L = 1,2-phenylenediamine (3) and 4,5-dimethyl-1,2-phenylenediamine (4)) were synthesized from [Mn(μ-OOCCMe₃)₂(HOEt)] _n (1) polymer and arenediamines in MeCN solution. The tetranuclear cluster Fe₄(μ₃-OH)₂(μ-OOCCMe₃)₄(η²-OOCCMe₃)₂(EtOH)₆ (5) was prepared by reacting FeSO₄·7H₂O with KOOCCMe₃ in EtOH and was used as starting pivalate iron(II) agent in further reactions. The thermolysis of 5 in MeCN was shown to result in a ferromagnetic polymer [Fe(μ-OOCCMe₃)₂] _n (6) containing tetrahedral iron(II) atoms. Cluster 5 was found to react with o-phenylenediamine giving rise to ferrimagnetic polymer [Fe(μ-OOCCMe₃)₂(HOEt)]_n (7). The reaction 7 with 2,6-diaminopyridine in MeCN results in binuclear antiferromagnetic complex (2,6-(NH₂)₂C₅H₃N)₂Fe₂(μ-OOCCMe₃)₄· 4MeCN (8). However the reaction of 4,5-dimethyl-1,2-phenylenediamine with polymer 7 yields a polymer {[L₂Fe(μ-OOCCMe₃)₂][Fe₂ (μ-OOCCMe₃)₄]} _n (9), which is an analogue of the manganese polymer 4. All newly synthesized compounds were characterized by the by X-ray diffraction studies and magnetic measurement. Dedicated to Professor Ilya I. Moiseev in recognition of his outstanding contribution to cluster chemistry     

O-Tolyldithiocarbonate Complexes of Iron(II) and Iron(III)

Abstract

Reactions of O-tolyldithiocarbonate ligands, (o-, m-, and p-CH₃C₆H₄O)CS₂Na, with anhydrous FeCl₂ (1:2 molar ratio) and with FeCl₃ (1:1 and 1:3 molar ratio) yielded the complexes [{(CreO)CS₂}₂Fe] and [{(CreO)CS₂}_nFeCl_3–n] (Cre = o-, m-, and p-CH₃C₆H₄; n = 1 and 3), respectively. These complexes were reacted with nitrogen and phosphorus donor ligands in dichloromethane, which afforded the adducts corresponded to [{(CreO)CS₂}₂Fe.xL] and [(CreO)CS₂FeCl₂.xL] {x = 1, L = N₂C₁₂H₈; x = 2, L = NC₅H₅, P(C₆H₅)₃}. Elemental analyses and IR, UV-visible, and mass spectroscopic and magnetic studies indicated bidentate mode of bonding by dithiocarbonate ligands leading to sixcoordination around the iron atom as a consequence of Fe…Fe interaction in the complexes [{(CreO)CS₂}₂Fe] and [(CreO)CS₂FeCl₂]. The complexes exhibited antifungal activity. The fungicidal activity of the complexes has been tested by poisoned food technique using fungi Fusarium sp.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental resource: Antifungal Activity.     

Coprecipitation of Amino Acids with Mixed Hydroxide of Iron(III) and Copper(II)

Abstract

A coprecipitation method for concentrating amino acids from aquatic environments with a mixed hydroxide of iron(III) and copper(II) was developed. The percent coprecipitation of glycine, alanine, glutamic acid, aspartic acid, and lysine, being independent of pH in the range of 8.5 to 9.5, was more than 95%.     

Iron(II) and Iron(III) Perchlorate Complexes of Ciprofloxacin and Norfloxacin

The reactions of ciprofloxacin (CIP) and norfloxacin (NOR) with iron(II) and iron(III) perchlorate have been investigated. The optical spectra support the formation of four complexes for each oxidation state with 1 : 1, 1 : 2, 1 : 3 and 1 : 4 metal to ligand molar ratios. The electrical conductivity and magnetic susceptibility measurements show that the isolated complexes are high spin and the Fe(ClO 4 ) 2 and Fe(ClO 4 ) 3 complexes behave as 1 : 2 and 1 : 3 electrolytes, respectively. The IR spectra indicate that CIP and NOR bind to the iron ion as bidentate ligands through the carbonyl oxygen atom and one of the oxygen atoms of the carboxylate group.     

Complex Formation Equilibria of Iron(III) With 2-Hydroxy-3- Pyridinol and 2-Mercapto-3-Pyridinol. Spectrophotometry Determination of Iron(III) In Multivitamins

ABSTRACT

The complex equilibria of iron(III) with 2-hydroxy-3-pyridinol (HHP), and 2-mercapto-3-pyridinol (MHP) were studied spectrophotometrically in 40% (v/v) ethanol and an ionic strength of 0.1M (NaCIO₄). The complexation reactions were demonstrated and characterized using graphical logarithmic analysis of the absorbance pH-graphs. After considering all the different parameters a simple, rapid, sensitive and selective method for spectrophotometric determination of trace levels of iron(III) was proposed based on the formation of (Fe -MHP) complex at pH 2.5 (λ_max = 640 nm, ? = l×10⁴ L mol^?1 cm^?). The interference of a large number of foreign ions was investigated. The method has been applied successfully for the determination of iron content in some multivitamins with mineral preparations and infant milk products.     

Iron(III) and nickel(II) template complexes derived from benzophenone thiosemicarbazones

New iron(III) and nickel(II) chelates were synthesized by template reaction of 2,4-dihydroxy- and 2-hydroxy-4-methoxy-benzophenone S-methylthiosemicarbazones with 2-hydroxy- and 5-bromo-2-hydroxy-benzaldehydes. The template complexes were isolated as stable solids and characterized by elemental analysis, conductivity and magnetic measurements, IR, ¹H NMR, UV–Visible, and mass spectra. The crystal structure of N ¹-(2-hydroxy-4-methoxyphenyl)(phenyl)methylene-N ⁴-(2-hydroxy-phenyl)methylene-S-methyl-thiosemicarbazidato-Fe(III) was determined by X-ray diffraction. A five-coordinate, distorted square-pyramidal geometry was established crystallographically for the iron(III) complex. Cytotoxicity and proliferation properties were determined using human erythromyeloblastoid leukemia and HL-60 mouse promyelocytic leukemia cell lines. For K 562 and HL-60 cells, compounds 1a and 2b were found to be cytotoxic at concentrations of 10 and 20 µg mL^?1.     

A Complexo-Ion Exchange Method for the Sensitive and Selective Detection Of Iron (III) and Molybdenum(VI) on Antimony(V) Silicate Beads

Abstract

A highly sensitive and selective spot test method has been developed for iron(III) and molybdenum(VI) with a limit of detection 0.01 μg per 0.02 ml and 0.001 μg per 0.02 ml for Fe(III) and Mo(VI) respectively on the beads of antimony(V) silicate cation exchanger. The method utilizes the adsorption ion-exchange properties of antimony(V) silicate and the complex forming ability of sodium diethyldithiocarbamate.     

Quantitative Separation of Iron from some Multivitamin-Multimineral Formulations using Zirconium (Iv) Arsenophosphate Columns

Abstract

Iron has been separated quantitatively from various multivitamin-multimineral formulations on zirconium(IV) arsenophosphate columns. The method is simple and selective with a high degree of accuracy and precision.     

Determination of Serum Iron and Iron Binding Capacity Using 4-(2-Pyridylazo) Resorcinol (Par)

Abstract

Procedures are described for the determination of serum iron and iron binding capacity using the chromogenic reagent 4-(2-pyridylazo) resorcinol (PAR). The high molar absorptivity of the iron (II) PAR complex makes possible an approximate two fold increase in sensitivity over previous methods. The described procedures have few interferences, and give linear results for samples containing 0 – 750 μg/dl of iron.     

Catalytic Kinetic Determination of Trace Amounts of Iron(III) With Polarographic Detection

Abstract

This method is based on the catalytic effect of Fe³⁺ on the oxidation reaction between Acid Chrome Blue K and potassium bromate in sulfuric acid medium at 100deg;C, and in 0.08 mol/L NH₄OH - 0.01 mol/L (NH₄)₂ SO₄ supporting electrolyte, Acid Chrome Blue K exhibits a sensitive polarographic wave at -0.55V vs. SCE, and change of concentration is traced by a polarographic detection technique. The linear range of Fe³⁺ is 10–100ng/mL. This new catalytic method has been applied to the determination of iron in natural water and food with satisfactory results.     

Spectrophotometric Determination of Copper(II) as the Azide Complexes,in the Presence of Iron(III) Cations

Abstract

A method for the spectrophotometrio determination of copper(II), in the presence of iron(III) cations (excess), was stablished. The masking of iron is made with sodium fluoride salt in 50 % (v/v) water/acetone medium. In the recommended conditions, absorbances for cupric complexes are measured at 435 nm where molar absorptivity is 6.00 × 10³ 1 mol^?1 cm^?1.

The stable ayetern obeys Beer's law and is suitable for the copper determination in concentration range from 2.0 to 9.0 mg 1^?l. The iron(III) ion interference (until ca. 600 mg 1^?l) can be completely suppressed. The influence of diverse ions and several others factore were studied.

The results show that copper(II) can be accurately determined by azide apectrophotometric method, if the samples were suitablely treated by the recommended procedure.     

Iron(III), nickel(II) and zinc(II) complexes based on acetophenone-S-methyl-thiosemicarbazone: synthesis,characterization, thermogravimetry,and a structural study

New complexes, [Fe(L)Cl], [Ni(L)], and [Zn(L)C₂H₅OH] (1–3), were synthesized by template reaction of 2-hydroxy-acetophenone-S-methyl-thiosemicarbazone with 2-hydroxy-benzaldehyde. The compounds were characterized by elemental analysis, magnetic measurements, FT-IR, ¹H NMR, UV–visible, and ESI–MS spectra. In these complexes, the ligand is coordinated to the metal ion as dinegatively charged tetradentate chelating agents via the N₂O₂ donor set. The iron(III) and zinc(II) complexes exhibit square pyramidal geometry whereas the nickel(II) complex has a square planar geometry. The crystal structure of 1, determined by X-ray diffraction method, indicates that 1 crystallizes in the monoclinic space group P21/c with Z = 4. Thermal decompositions of the compounds have been investigated using TGA in air.     

Iron(III) chloride and its coordination chemistry

Abstract

The coordination chemistry of FeCl₃ is distinctly different to that of the other 3d metal halides. It has a distinct preference for O-donor ligands. Although it primarily forms six-coordinate complexes, it has some distinctive features that set it apart from metals like Mn(II), Co(II), and Ni(II), such as the self-ionized complexes [FeL₄Cl₂]⁺ [FeCl₄]^?. There are a number of examples where very small changes in the coordination sphere tilt the balance between isomeric structures. Chloride has a significant steric effect in the coordination sphere as well as a greater trans-influence than water.     

Spectrophotometric Determination of Iron(III) as Azide Complexes in Aqueous Tetrahydrofuran

Abstract

A simple, sensitive and alternative method for the spectrophotometric determination of iron(III) has been established. The procedure is based on the formation of iron-azide complexes in 60% (v/v) tetrahydrofuran/ water medium. The high sensitivity obtained in this method is due to the use of an interesting absorption band not previously reported in the literature. In the recommended conditions, absorbances for the ferric complexes are measured at 400 nm where the molar absorptivity is 1.52 × 10⁴ 1 mol^?1 cm^?1. The organic solvent used increases the sensitivity and the stability of the measurements. The precision is shown by the average deviation of about 0.3%. This system obeys Beer's law and is suitable for iron(III) determination in the concentration range from 0.6 to 3.2 mg 1^?1 (ppm). The best experimental conditions were determined studying the different factors involved. The influence of various diverse ions was also studied.     

A New Spectrophotometric Method for Determination of Microgram Amounts of Iron (II) in Pharmaceuticals

Abstract

A new spectrophotometric method was developed for the assay of 0–6 mg/1 of iron (II) in a number of certified Iraqi drugs. The Sandell index is 0.07 μg cm^2- and the ? max is 6000 1 mol^?1 cm^?1. An interference study is also described.     

Construction of a New Perbromate-Selective Electrode. Kinetic Study of the Iron(II)- Perbromate Reaction and Microdetermination of Iron

Abstract

A perbromate- selective membrane electrode with a liquid membrane of crystal violet-perbromate dissolved in chlorobenzene is described, The liquid membrane electrode exhibits rapid and near Nernstian response to perbromate activity from 10^?5 to 10^?2 M. The response is unaffected by pH in the range 2–10, Major interferences are periodate and perchlorate. A kinetic study of the iron(II)- perbromate reaction was carried out with the perbromate electrode, A potentiometric method is described for the determination of 50–500 μg of iron (II) with relative errors and standard deviations of 1–2%.     

Simultaneous Polarographic Determination of Iron (II) and Iron (III) in Coal Mine Waste Water

Abstract

Polarography with a sodium carbonate-oxalic acid supporting electrolyte was used to determine both Fe(II) and Fe(III) simultaneously in actual coal mine water samples. The average relative percent error was 2.2% for Fe(II) and 2.1% for Fe(III) over a range of 10 to 500 ppm. In actual mine water the Fe(II) content was highest where the mine water emerged. As the water moved down stream from the source of pollution Fe(II) decreased and Fe(III) concentration increased as Fe(II) was oxidized to Fe(III) by oxygen. This was accompanied by a decrease in pH. Further down the stream Fe(III) started to precipitate and then its concentration steadily decreased.     

Determination of Iron(II) in Pharmaceuticals Using Chlorpromazine Hydrochloride as a Redox Indicator

Abstract

Titrimetric method for the determination of (1–100) mg/L iron(II) as pure solutions and in its dosage forms was investigated and found to offer an improvement in ease, speed and accuracy. This method is based on the direct visual titration of iron(II) with ceric amnonium sulphate and employs chlorpromazine hydrochloride in a mixture of sulphuric and phosphoric acids as a redox indicator.

An interference study is carried out for the differant acids and cations. Data obtained for sevceral pharmaceuticals are reported and compared with those obtained potentiometrically. Formal redox potential was determined to be 285 mv.     

Spectrophotometric Investigation of Iron(III)-N-Phenylcin-namohydroxamic Acid System

Abstract

N-Phenylcinnamohydroxamic acid, PCHA, was found to react with iron (III) to form complex species of different colour depending upon the reaction environment. The reaction conditions for the formation of the complex species were studied in aqueous-ethanolic medium. The general spectral properties of the species were investigated. The absorption curves were found to have two isobestic points. The number and composition of the complexes were determined and found to have composition 1:1, 1:2, 1:3 (Fe: PCHA). The wavelengths of the maximum absorbances were figured out to be 535, 495, and 445 nm for the I, II, and III complex species, respectively. It was verified that the Beer's law holds for these complexes at all wavelengths, and for the mixtures at the wavelengths of the isobestic points in a wide range of pH. The stepwise stability constants have been determined by the method of isobestic point and found to be log K₁ = 11.55, log K₂ = 10.11, and log Kg₃ = 7.44 for the I, II, and III complex species, respectively. The distribution diagrams (nomograms) of the complex species as a function of pH were constructed and the molar extinction coefficients of the three consecutive complexes have also been determined.     

Iron(III) complexes with 2-aminobenzothiazole: compounds governed by non-covalent interactions

Two new iron(III) coordination compounds with 2-aminobenzothiazole have been prepared and identified as (C₆H₄NHC(NH₂)S)₂[FeCl₄]Cl(H₂O) (1) and (C₆H₄NHC(NH₂)S)₃[Fe(C₂O₄)₃](H₂O)₂ (2). The compounds were characterized by thermogravimetric analysis in conjunction with evolved gases in air and spectroscopic studies. On the basis of quantum-mechanical calculations the interplay between two non-covalent interactions in 1, anion?···?π and ion-pair interactions, was analyzed.