Facile synthesis of superparamagnetic manganese ferrite nanoparticles as a novel T2 MRI contrast agent

With co-precipitation method we successfully synthesized an aqueous dispersible, superparamagnetic manganese ferrite nanoparticles at relatively low temperature (190 ​°C). This material shows potential application as T₂ MRI contrast agent. Cost-effective and less toxic manganese (II) chloride (MnCl₂·4H₂O) and iron (III) chloride hexahydrate (FeCl₃·6H₂O) were used as precursors and 2-[2-(2-Hydroxyethoxy)ethoxy] ethanol (TEG) were utilized as solvent which served as stabilizer and provided a reduction system. The mean diameter of these nanoparticles is about 7 ​nm. Its saturation magnetization (Ms) and relaxivity value (r₂) are as high as 46 emu/g and 593.9 ​mM⁻¹s⁻¹ respectively. In vitro cell study demonstrated pancreatic cancer cells could keep viable when the manganese ferrite nanoparticles concentration reached up to 50 ​μg/mL.     

FERRIC CHLORIDE HEXAHYDRATE: A CONVENIENT REAGENT FOR THE OXIDATION OF HANTZSCH 1,4-DIHYDROPYRIDINES

A general and practical route for the moderate yield oxidative conversion of readily accessible 1,4-dihydropyridines (1,4-DHPs) to the corresponding pyridines was described using a relatively benign oxidant, i.e. ferric chloride hexahydrate (FeCl₃·6H₂O). The reaction was carried out under mild and convenient condition. However, oxidation of 4-isopropyl-1,4-DHP 1b with FeCl₃·6H₂O afforded the dealkylated pyridine 2a.     

Electrical properties of K2FeCl5·H2O and K2AlF5

The electrical conductivity of nominally pure K₂FeCl₅·H₂O and anhydrous K₂AlF₅ has been studied from 300 to 690°K. K₂FeCl₅·H₂O exhibits mixed ionic and electronic conduction, whereas K₂AlF₅ is a pure ionic conductor. The mass and charge transport processes in K₂FeCl₅·H₂O seem to be governed by deviations from both molecularity and stoichiometry. At elevated temperatures both potassium and chloride ions are mobile in K₂FeCl₅·H₂O.     

Nanofiber cellulose di- and tri-acetate using ferric chloride as a catalyst promoting highly efficient synthesis under microwave irradiation

An efficient method for the generation of cellulose di- and tri-acetate nano-structures is obtained through testing ferric chloride hydrate (FeCl₃·6H₂O) as a valuable Lewis acid catalyst with acetic anhydride under microwave irradiation. Our target was to evaluate the effects of the reaction conditions on the products' properties such as surface area and particle size distribution. It was found that changes in the degree of substitution (DS), the surface area, the degree of polymerization and the particle size distribution of the products correlated with reaction conditions. Cellulose tri-acetate nanofibers with DS of 2.94 with 98.03% yield was prepared using 200 mg of FeCl₃·6H₂O, 25 ml of Ac₂O and 4 minutes of microwave irradiation. Also, cellulose di-acetate nanofibers were prepared with DS values ranged between 2.37 and 2.72 with yield ranged between 78.92 and 90.58%. The percentage of acetyl groups (Ac%) as well as the BET specific surface area, total pore volume, mean pore diameter, mono layer volume and the mean particle size of the products were determined. The maximum specific surface area obtained for the acetylated cellulose was about ten times larger than that measured for the commercial cotton cellulose and about six times larger than that of the commercial cellulose acetate. The lowest mean particle size (34.90 nm) was about eleven times smaller than the mean particle size of the commercial cellulose acetate (394 nm). The present work has proved that FeCl₃·6H₂O was a highly active catalyst for the esterification of cellulose with unexpected yields and for the formation of nanofibers with low molecular weight.     

A Sustainable Synthesis of 2‐Benzoxazyl and 2‐Benzothiazyl Ketones from Alkynyl Bromides and 2‐Amino(thio)phenols Promoted by a Recyclable Catalytic System

An environmentally and economically sustainable synthesis of 2‐benzoxazyl ketones and 2‐benzothiazyl ketones through FeCl₃·6H₂O catalyzed tandem reactions of alkynyl bromides with 2‐amino(thio)phenols in [bmim]BF₄ has been developed. Remarkable advantages of this new synthetic strategy include high efficiency, readily available starting materials, and recyclable catalyst and reaction medium.     

Synthesis of 5-hydroxymethylfurfural from glucose in a biphasic medium with AlCl<Subscript>3</Subscript> and boric acid as the catalyst

In combination with non-corrosive and low-toxic boric acid, AlCl₃ · 6H₂O was found to be effective for the synthesis of 5-hydroxymethylfurfural (5-HMF) from glucose. In this work, a 5-HMF yield of ≈ 60 % was obtained at 170°C for 40 min in a H₂O/THF biphasic solvent mixture. An addition of NaCl not only improved the partition coefficients but also inhibited by-product formation. THF was identified as an ideal extraction solvent in biphasic systems containing C4 solvents. However, low concentration of ZnCl₂, CoCl₂ · 6H₂O, MnCl₂ · 4H₂O, NiCl₂ · 6H₂O, FeCl₃ · 6H₂O were not suitable for the catalyst system, while ZrOCl₂ · 8H₂O, InCl₃ · 4H₂O showed high activity for the reaction. Boric acid increased the amount of Lewis acid sites in the reactive phase and enhanced the isomerization of glucose to fructose. A mechanism of the AlCl₃ · 6H₂O and boric acid catalyzed glucose dehydration reaction was proposed to proceed through the isomerization of glucose to fructose followed by the transformation of fructose to 5-HMF.     

Thermisches Verhalten von Caesiumchloroferraten(III) und Caesiumchloroferrat(III)-Hydraten. II. Die Rehydratation der Zersetzungsprodukte von Cs3[FeCl6] – Eine ramanspektroskopische Untersuchung unter definierter Wasserdampfatmosphäre [1]

The Thermal Behaviour of Caesiumchloroferrates(III) and Caesiumehloroferrate(III) Hydrates. II. The Rehydration of Decomposition Products of Cs₃[FeCl₆] — A Raman Spectroscopic Study under Definite Atmosphere of Water Vapour Cs₃[FeCl₆] formed by dehydration of Cs₃[FeCl₆] · H₂O at about 160°C does not change at normal atmosphere within 3 till 4 hours. Rehydration under the vapour pressure of the eliminated water yields the monohydrate in nearly the same time. In the same manner rehydration of the solid mixture of Cs[FeCl₄] and 2 CsCl formed by thermal decomposition of the metastable Cs₃[FeCl₆] (280°C) produces the intermediates Cs₃[Fe₂Cl₉] and Cs₂[Fe(H₂O)Cl₅] in mixtures with CsCl and, finally, Cs₃[FeCl₆] · H₂O. The formation of Cs₃[Fe₂Cl₉] from Cs[FeCl₄] and CsCl is accelerated by water. The reaction cycle has been studied using Raman and IR spectroscopy. The results will be discussed with respect to thermoanalytical data.     

Komplexchemie polyfunktioneller Liganden. XXXI. Komplexe des Tetrakis(diphenylphosphorylmethyl)-methan mit FeCl3, SnCl4 und SbCl5

Complex Chemistry of Polyfunctional Ligands. XXXI. Complexes of Tetrakis(diphenylphosphorylmethyl) methane with FeCl₃, SnCl₄, and SbCl₅ C[CH₂P(O)(C₆H₅)₂]₄ forms with FeCl₃ the compounds C[CH₂P(O)(C₆H₅)₂]₄ · 2FeCl₃ and C[CH₂P(O)(C₆H₅)₂]₄ · 4 FeCl₃. From their IR spectra ionic, spirocyclic structures have been derived. C[CH₂P(O)(C₆H₅)₂]₄ yields with SnCl₄ and SbCl₅ also spirocyclic compounds of the composition C[CH₂P(O)(C₆H₅)₂]₄ · 2 SnCl₄ and C[CH₂P(O)(C₆H₅)₂]₄ · 4 SbCl₅, but the SnCl₄ derivative has a nonionic structure.     

Quantum-dots containing Fe/SBA-15 silica as “green” catalysts for the selective photocatalytic oxidation of alcohol (methanol,under visible light)

Fe/SBA-15 catalysts containing iron oxide nanoparticles confined inside silica pores (replicated, internal, poorly crystalline) and grown outside silica grains (external, mainly crystalline hematite) in different proportions are prepared using a single silica support. Fe-species are deposited by the two-solvent technique with two iron salts precursors (Fe(NO₃)₃·9H₂O, FeCl₃·6H₂O) and two solvents (cyclohexane, hexane) for 11 wt% of iron. Calcination is performed in reproducible conditions (700 °C, 2 °C/min, thin bed, in air). SAXS measurements are used to show that the 2D hexagonal structure of the used silica is maintained after Fe-loading and calcination. Ar sorption measurements show that the pores are partially plugged. The oxidation of pure methanol is used as a test reaction to compare photocatalytic properties. H₂O₂ and visible light both activate the reaction. More active catalysts are formed with hexane associated with FeCl₃·6H₂O than with Fe(NO₃)₃·9H₂O. A reversed situation is observed with cyclohexane. Iron leaching (after 1 h 30 of test, up to 3 mg of Fe by mL) is important. These results are expected to be of interest in the exploration of size and shape “nanocatalysis” and to provide a further understanding for the reactions that take place when porous silicas are used as supports.     

Über die Entstehung ferromagnetischer Gele und einige verwandte Erscheinungen

Zusammenfassung Durch Zerreiben von Na₂SO₄·10 H₂O, MgSO₄·7 H₂O, MnSO₄·5 H₂O, NiSO₄·7 H₂O, CoSO₄-7H₂O, ZnSO₄·7H₂O CuSO₄·5 H₂O, CdSO₄·8— H₂O, HgSO₄ und (UO₂)·SO₄·3 H₂O mit FeCl₃·6 H₂O werden ferromagnetische Gele erhalten. Durch Autoklavbehandlung dieser Gele entstehen Niederschl?ge, die in ihrem Aussehen weder H?matit noch Magnetit ?hnlich erscheinen. Es wird ein Demonstrationsversuch beschrieben, mit dem der Unterschied der magnetischen Eigenschaft von Eisenhydroxyden je nach der Herstellungsart veranschaulicht wird. Die beim Mischen von Ferro- und Ferril?sungen entstehenden Farb?nderungen werden photometrisch gemessen und diskutiert.     

Catalytic conversion of raw <Emphasis Type="Italic">Dioscorea composita</Emphasis> biomass to 5-hydroxymethylfurfural using a combination of metal chlorides in <Emphasis Type="Italic">N,N</Emphasis>-dimethylacetamide solvent containing lithium chloride

We synthesized 5-hydroxymethylfurfural (HMF) from carbohydrates using metal chloride catalysts. A 33.2 % yield of HMF was obtained from raw Dioscorea composita biomass with high starch by using a catalyst system composed of CrCl₃·6H₂O and LaCl₃·6H₂O at 120 °C for 4 h in N,N-dimethylacetamide containing lithium chloride. The catalyst system is also cost-effective for the conversion of soluble starch into HMF. In addition, levulinic acid was not formed in the reactions.     

Germanium(IV) bischelates with 2-hydroxynaphthaldehyde pyridinoylhydrazones: The crystal and molecular structure of the complex with isonicotinoylhydrazone (H<Subscript>2</Subscript>Inf), [Ge(Inf · HCl)<Subscript>2</Subscript>] · 5H<Subscript>2</Subscript>O

The reactions of GeCl₄ with 2-hydroxynaphthaldehyde pyridinoylhydrazones (H₂L) in methanol give complexes [Ge(L · HCl)₂] · nH₂O. The data of mass spectrometry, thermogravimetry, and IR and ¹H NMR spectroscopy indicate that the ligand molecules are protonated at the pyridine nitrogen atom with hydrogen chloride and coordinated to germanium in the tridentate mode through the azomethine nitrogen atom and the oxyazine and oxy group oxygen atoms. The structure of the complex with isonicotinoylhydrazone (H₂Inf), [Ge(Inf · HCl)₂] · 5H₂O has been determined by X-ray diffraction     

Determination of the electric field gradient tensor in ferrous chloride tetrahydrate using a polarized mössbauer source

The orientation of the electric field gradient tensor at the iron nucleus in a single crystal of FeCl₂·4H₂O has been determined using a polarized Mössbauer source of ⁵⁷Co in iron metal. The data analysis embodied an accurate thickness correction for the polarization of the absorption cross-section. The principal axis of the tensor lies close to the FeCl bonds of the trans-octahedral FeCl₂(H₂O)₄ unit, but the minor axes are directed between the FeO bonds. The value of the asymmetry parameter obtained, n = 0.40 ± 0.15, is significantly larger than previous estimates.     

Effect of the guest solvent molecules on preparation of different morphologies of ZnO nanomaterials from the [Zn2(1,4-bdc)2(dabco)] metal-organic framework

The host and the apohost framework of [Zn₂(1,4-bdc)₂(dabco)]?·?4DMF?·?½H₂O (1?·?4DMF?·?½H₂O) (1,4-bdc?=?1,4-benzenedicarboxylate and dabco?=?1,4-diazabicyclo[2.2.2]octane) were used for the preparation of ZnO nanomaterials. With calcination of the host framework of 1?·?4DMF?·?½H₂O, ZnO nanoparticles could be fabricated. By the same process on fully desolvated framework of 1, ZnO microrods composed of ZnO nanoparticles were formed. These results indicate with removal of the guest solvent from the pores of this metal-organic framework (MOF), nanoparticle agglomeration increases and the role of this MOF in preparation of ZnO nanoparticles was reduced.     

The solid state reactions of o-aminobenzoic acid with Zn(Ⅱ), Cu(Ⅱ), Ni(Ⅱ), Mn(Ⅱ) acetate hydrate at room temperature

The solid-solid state reactions of o-aminobenzoic acid with Zn(OAc)2.2H2O, Cu(OAc)2 .H2O, Ni(OAc)2.4H2O and Mn(OAc)2.4H2O result in the formation of corresponding complexes M(OAB)2 (M = Zn(Ⅱ), Cu(Ⅱ), Ni(Ⅱ), Mn(IⅡ)). XRD, IR and elemental analysis methods have been used to characterize the solid products. The activation energies of these reactions, which are calculated from the kinetic data obtained by means of the isothermal electrical conductivity measurement method, have been found to increase in the order: Cu(OAc)2.H2O(37.7 kJ.mol-1)~Mn(OAc)2.4H2O (39.7kJ.mol-1) < Zn(OAc)2.2H2O (56.3 kJ.mol-1) < Ni(OAc)2.4H2O (85.2 kJ.mol-1). The trend is related to their crystal structures.     

Phase transfer catalysis: Synthesis of monodispersed FePt nanoparticles and its electrocatalytic activity

Using dibenzo-24-crown-8-ether (DB24C8) as phase transfer catalyst, the monodispersed iron–platinum (FePt) alloy nanoparticles with size of ∼17 nm were synthesized by reduction of H₂PtCl₆·6H₂O and FeCl₂·4H₂O in the solvothermal system. The structure, magnetic property and electrocatalytic activity of FePt nanoparticles were characterized by transmission electron microscopy (TEM), X-ray diffraction system (XRD), vibration sample magnetometer (VSM) and CHI 820 electrochemical analyser (three electrodes system, the reference electrode is saturated calomel electrode (SCE), the counter electrode is platinum electrode and the glassy carbon electrode is used as working electrode (GCE)), respectively. The results show that the as-synthesized FePt nanoparticles have a chemically disordered fcc structure and can be transformed into chemically ordered fct structure after annealing treatment above 400 °C, simultaneously accompanying with the coercivity changed from 5 to 2400 Oe. CVs of 0.5 M H₂SO₄/0.5 M CH₃OH on GCE modified with FePt nanoparticles monolayer illustrate that the as-synthesized FePt nanoparticles have strong electrocatalytic activity toward the oxidation of CH₃OH in aqueous solution.     

Diagramme Polythermique Du Systeme Ternaire KCl–FeCl2–H2O Entre 0 Et 70°C

Polytherm diagram of the ternary system KCl–FeCl₂ –H₂ O between 0 and 70°C. Phase equilibria in the KCl–FeCl₂ –H₂ O system were studied over the temperature range 0–70°C by conductimetric and analytical methods. A solubility polytherm of the system was constructed. We have observed the crystallization fields of the KCl and FeCl₂ 6H₂ O (at 0°C), KCl and FeCl₂ 4H₂ O (at 15, 30 and 40°C) and KCl, FeCl₂ 4H₂ O and of a double salt KClFeCl₂ 2H₂ O are obtained at 70°C. This revised version was published online in July 2006 with corrections to the Cover Date.     

FeCl2-Na2SO3-H2O system as a basis for recovery of iron(II) sulfite from solution

The FeCl₂-Na₂SO₃-H₂O system was studied along seven sections with the molar ratios Na₂SO₃: FeCl₂ = 5: 1, 5: 2, 5: 3, 5: 4, 5: 5, 5: 10, and 5: 15, including six points on each section where pH ranges from 1.5 to 4.0 in 0.5 steps. Equal-undersedimentation lines for cations and anions were plotted. The iron(II) system forms sodium ferrisulfites NaFe₅O_0.5(SO₃)₅ · 5H₂O, NaHFe₅(SO₃)₆ · 5H₂O, Na₂Fe₅(SO₃)₆ · 4H₂O, and NaHFe₂(SO₃)₃; the iron(III) system forms Na₂Fe₆(SO₃)₇ · 10H₂O. The regions where these compounds sediment were demarcated, and their characterizations were carried out.     

A Triazolate-Supported Fe<Subscript>3</Subscript>(<Emphasis Type="Italic">μ</Emphasis><Subscript><Emphasis Type="Italic">3</Emphasis></Subscript>-O) Core: Crystal Structure,Fluorescence, and Hirshfeld Surface Analysis

One new trinuclear Fe(III) cluster with a Fe₃(μ ₃-O) core was synthesized by the method of hydrothermal synthesis. The complex [Fe₃(μ ₃-O)(pmta)₆(H₂O)₃]FeCl₄·2H₂O (1) (where Hpmta is 5-methyl-1-phenyl-1H-1,2,3-triazole-4-carboxylic acid) was characterized by single-crystal X-ray diffraction methods, elemental analyses, IR spectroscopy, fluorescence and Hirshfeld surface analysis. For complex 1, the crystal structure is extended into 3D structure through N–H···O and O–H···O hydrogen bonds. According to the 3D Hirshfeld surface and 2D fingerprint plots, the main interactions in the cluster are the H···H, N···H and C···H contacts.