Über Eisen(III)-Komplexe mit Phenolen. IV. Säurekonstanten einiger Polyphenole

The apparent acid constants of some polyphenols and of derivates from salycilic acid are determined by potentiometry using glass or hydrogen electrodes and by UV spectrophotometry on comparable conditions respectively. Anaerobic manipulations were strictly used to avoid autoxidation. The results can be interpreted qualitatively, if the possibility of the formation of intramolecular hydrogen bridges is considered besides the effects of substituting groups.     

Über Ternäre Chelate des Eisen(III)-Ions mit Nitrilotriessigsäure und Phenolderivaten

On Ternary Chelates of the Iron(III) Ion formed with Nitrilo-Triacetic Acid and Derivatives of Phenol Ternary chelates of iron(III) ions are produced with nitrilo-triacetic acid and some derivatives of phenol in aqueous solution. Their reactions of formation have been controlled by spectro-photometric methods. The ratio of components in the compounds Fe: X: L is 1: 1: 1 without any exception. The measured optical properties (λ_max, ε_max) of the ternary chelates are discussed and compared with the corresponding binary iron(III) phenol chelate.     

Spektrophotometrische Untersuchung der Komplexbildung von Eisen(III) mit Ethylendiamintetraessigsäure und einigen Thioliganden

Spectrophotometric Investigation of the Complexation of Iron(III)with Ethylene Diamine Tetraacetic Acid and Some Thioligands . In the system Fe^III/EDTE/R? SH (Thiophenol, Toluen-3,4-dithiol, Thioethanol bzw. Thioglycollic acid) ternary complexes could be detected in solution. By means of spectrophotometric measurements the ratio of components in the species Fe:L:L′=1:1:1 was determined. The optical properties of the complexes are discussed.     

Spektrophotometrische Untersuchung der Eisen(III)-Komplexe mit o-Methylbenzamidoxim

The complex formation of Fe³⁺ with o-methyl benzamide oxime was studied spectrophotometrically in methanol solution. The stepwise process gives complexes 1∶1, 1∶2 and 1∶3. The formation constants are lgK ₁ = lg β₁ = 1,88 ± 0,12, lgK ₂ = 3,53 ± 0,2, lgK ₃ = 4,96 ± 0,2, lg β₂ = 1,65 ± 0,32 and lg β₃ = 1,43 ± 0,4, whereK ₃ = β₁ · β₂ · β₃. All measurements were carried out at 25°C and an ionic strength μ=1.     

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.     

Elektrometrische Untersuchungen über die Komplexbildung von La(III) mit 3.5-Dinitrosalicylsäure

Zusammenfassung Die Komplexbildung zwischen La(III) und 3.5-Dinitrosalicylsäure in 0.1m-KNO₃ wurde potentiometrisch und konduktometrisch untersucht. Wir erforschten die Bildung von 11- und 12-Komplexen oberhalb pH 3.5. Der 11-Komplex bildet sich in Lösung, während der 12-Komplex ausfällt. Die Stabilitätskonstante des 11-Komplexes wurde durch Anwendung der vonCalvin undMelchior erweiterten Methode vonBjerrum bestimmt. Für logK fand man Werte von 4.92, 5.00 und 5.12 bei 25°, 30°, beziehungsweise 35° C. Die Werte für F, H und S wurden für 30° C berechnet und bestimmt zu–6.97 Kcal/Mol,–7.49 Kcal/Mol, beziehungsweise –1.70 cal/Mol/Grad.

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Electromeric studies on the complex formation between La(III) and 3.5-dinitrosalicylic acid

The complex formation between La(III) and 3.5-dinitrosalicylic acid in 0.1m-KNO₃ medium has been studied potentiometrically and conductometrically. The formation of 11 and 12 complexes beyond 3.5 pH was investigated. 11 complex is formed in solution while 12 complex is precipitated. The stability constant of the 11 complex was determined by applying the Calvin and Melchior's extension ofBjerrum's method. The logK values have been found to be 4.92, 5.00, and 5.12 at 25, 30 and 35°C, respectively. The values of F, H, and S have also been evaluated at 30°C and found to be–6.97 Kcal/mole,–7.49 Kcal/mole, and–1.70 Kcal/mole/degree, respectively.

     

Ternäre Komplexe von Eisen(III) mit Ethylendiamintetraessigsäure und Monophenolderivaten

Ternary Complexes of Iron(III) with Ethylene Diamine Tetraacetic Acid and Derivatives of Monophenols Ternary complexes of iron(III) are investigated with ethylenediamine tetraacetic acid and some monophenols in solution as well as their reactions of formation have been controlled by spectrophotometric and elektrophoretic methods. The ratio of components in the compounds Fe: Y: L is 1: 1: 1 without any exception. The measured optical properties (λ_max' ?_max) of the complexes are discussed.     

Die Reaktion von Eisen(III) mit Brenzkatechin-3,5-disulfonsäure (Tiron) und Äthylendiamintetraessigsäure

The Reaction of Iron(III) with Catechol-3,5-Disulphonic Acid (Tiron) and Ethylene Diamine-Tetracetic Acid In the system iron(III)-Tiron-EDTA a ternary chelate could be detected besides the well known complexes in a weak acid solution. By means of spectro-photometric measurements under various conditions (concentration of ligands) we found [FeHYL]^4? with λ_max = 555 nm und ε₅₅₅ = 2500 l · mol^?1 · cm^?1. The formation of the ternary chelate is an inner-complex reaction of displacing, in which donor atoms of the EDTA in FeY^? are replaced by Tiron. By graphic methods the equilibrium constants could be calculated from the measurements.     

Über die Reaktion von Phenolen mit N-substitutierten Maleinimiden

The Reaction of Phenols with N-substituted Maleinimides Phenoxysuccinimides are formed by the base catalysed addition of phenols to N-substituted maleinimides. In the presence of catalytic amounts of tertiary aliphatic amines yields as high as 90% are obtained. A series of adducts of mono-and di-phenols to mono- and bismaleinimides is described. Pure phenoxysuccinimides are stable compounds but the basic catalysts of their formation give rise to their decomposition into the phenolic component and oligomeric maleinimide. A nucleophilic reaction mechanism both for the formation and the decomposition is discussed. A new crosslinked addition polymer from a diphenol and a bismaleinimide with a surprisingly high heat stability is described.     

Über Reaktionen oxygenierter Kobalt(II)-Komplexe. V. Reaktivität diastereoisomerer μ-Peroxo-μ-hydroxo-dikobalt(III)-Ionen

On Reactions of oxygenated Cobalt(II) Complexes. V. Reactivity of diastereoisomeric μ-peroxo-μ-hydroxo-dicobalt(III) Ions The kinetics of dissociation of μ-peroxo-μ-hydroxo-dicobalt(III) chelates have been reinvestigated using a stopped flow technique. The binuclear cations [(trien)Co(O₂, OH) Co(trien)]³⁺, [(tren)Co(O₂, OH)Co(tren)]³⁺ and [(en)₂Co(O₂, OH)Co(en)₂]³⁺ dissociate on acidifying to Co²⁺ and the protonated ligand and up to 100% of the bound O₂ is evolved. The dissociation is H⁺-catalyzed and first order in complex. The observed rate constants at pH 2 are in the range of 10^?3 to 10^?1 s^?1 (20°). They depend not only on the nature of the ligand and on ligand configuration but also on the diastereoisomeric structure of the binuclear cation. In the case of trien there are 8 possible chemically different isomers. On oxygenation of Co(trien)²⁺ in dilute solution 3 of those isomers seem to be formed preferentially. Their rate constants are separated over a factor of 50. For [(en)₂ Co(O₂, OH)Co(en)₂]³⁺ there exist a meso form and a chiral structure. On oxygenation of Co(en)₂²⁺ in dilute solution the meso form and the racemate are formed to about equal amounts. The racemate dissociates about 5 times slower. Of the 3 possible achiral isomers of [(tren)Co(O₂, OH)Co(tren)]³⁺ one is formed stereoselectively by oxygenation in solution.     

Über Oberflächenverbindungen von Übergangsmetallen. VIII. Die Komplexbildung von koordinativ ungesättigtem Oberflächen-Chrom (II) mit Oxiden des Stickstoffs

On Surface Compounds of Transition Metals. VIII. Complex Formation of a Coordinatively Unsaturated Cr^II Surface Compound with Nitrogen Oxides N₂O forms with surface-Cr(II) a relatively unstable light blue compound of the stoichiometry 1:1, while addition of NO results in formation of a very stable dark brown, diamagnetic surface complex . By reaction with O₂ this complex undergoes — depending on reaction temperature — either replacement of NO unter reoxidation of the metal (→Cr(VI)) or/and reaction of the ligand (→NO₂). Direct reaction of NO₂ with results in the same products as stepwise addition of NO and 1/2 O₂. reacts with HCl/ROH under formation of the soluble, paramagnetic kation [Cr(NO)(ROH)_n]²⁺, which is formulated as [Cr(II)(NO)]²⁺ ? [Cr(I)(NO⁺)]²⁺ accordingly to the e.s.r. spectra.     

Über die Umsetzung von Mangan(III) mit Acetylchlorid und die Fällung von Chloromanganaten in Essigsäure

In accordance with spectrophotometric measurements, manganese(III) acetate dihydrate reacts with dilute solutions of acetyl chloride in acetic acid through a 1:1 complex to a red-violet 1:4 compound which is unstable due to the oxidation potential of Mn^III ions. The action of potassium acetate on solutions of Mn^III in acetic acid in presence of a large excess of acetyl chloride leads to a dismutation of managanese(III) and initial precipitation of potassium chloromanganate(IV), K₂MnCl₆. During the reaction of potassium acetate with solutions of manganese(II)/acetic acid/acetyl chloride, under particular conditions, first nonsolvated potassium trichloromanganate(II), KMnCl₃, is formed, which transforms during further addition of potassium ions to tetrapotassium hexachloromanganate(II), K₄MnCl₆.     

Die Reaktion der 2,7-Dichlorchromotrops?ure mit Eisen(III)

Ohne Zusammenfassung     

Über Chalkogenocarbonate. XL. Untersuchungen über Dithiocarbamidsäure SC(SH)(NH2) 4. Reaktionen von Dithiocarbamaten mit Oxalylchlorid

2-Thioxo-1,3-thiazolidine-4,5-dione and some derivatives of this compound have been prepared by interaction of dithiocarbamic acid and N-substituted dithiocarbamates with oxalychloride (formula see ?Inhaltsübersicht”?). The chemical and physical properties of this new class of compounds are described.     

Über Chalkogenolate. 160. Umsetzung von 1,2-Ethandithiolaten mit Kohlenstoffdisulfid 2. 1,2-Ethan-bis(trithiokohlensäure) und Alkylester der Säure

On Chalcogenolates. 160. Reaction of 1,2-Ethanedithiolates with Carbon Disulfide. 2. 1,2-Ethane-bis(trithiocarbonic acid) and Alkyl Esters of This Acid The reaction of potassium 1,2-ethane-bis(trithiocarbonate) with hydrochloric acid at 0°C gives unstable, deep yellow coloured 1,2-ethane-bis(trithiocarbonic acid) The 1,2-ethane-bis(alkyl trithiocarbonates) RS? CS? SCH₂CH₂S? CS? SR, where R = CH₃ and C₂H₅, have been formed by reaction of potassium 1,2-ethane-bis(trithiocarbonate) with the corresponding alkyl iodide. The called compounds have been characterized by means of diverse spectroscopic methods.     

Spektrophotometrische Untersuchungen über die Komplexbildung von Niob(V) mit 7-Phenylazo-8-hydroxychinolin-5-sulfonsäure

Complex formation of Nb(V) with 7-phenylazo-8-hydroxyquinoline-5-sulphonic acid (Pazoxs) is described.Pazoxs forms a pinkish-orange water soluble complex with Nb(V). The stoichiometry of the complex is 12 (metal to ligand) as shown by moles ratio andJob's equimolar as well as nonequimolar continuous variation method. The complex shows maximum absorption at 480 nm. The most suitable pH range for complex formation was found to be 4.5–5.5. The present work was done at pH 5.0 at 29±1°C. Interference by various ions was studied and probable structures are suggested. Average value of the stability constant as found byJob's equimolar and non-equimolar and moles ratio method is 8.2 showing the complex to be sufficiently stable. Effect of time and temperature has also been studied.     

Reaktion oxygenierter Kobalt (II)-Komplexe. XII. Über einen binuclearen μ-Peroxodikobalt (III)-Komplex mit makrocyclischem Brückenring

Reactions of oxygenated cobalt(II) complexes. XII. A binuclear μ-peroxodicobalt(III) complex with a macrocyclic bridging ring

1 XI: siehe [1].

Singly bridged [(tren) (NH₃) CoO₂(NH₃) (tren)]⁴⁺ reacts with excess tren by replacement of NH₃ in cis-position to the peroxo group and formation of a new type of doubly bridged μ-peroxo complex. An X-ray structure determination of [(tren)-Co(O₂, tren)Co(tren)] (ClO₄)₄ · 2 H₂O showed that the additional tren forms a macrocyclic bridging ring. The conformation of the CoOOCo group is transoid with a dihedral angle of 20°. The crystals are monoclinic with space group P2₁/c. The lattice constants are a = 9,798, b = 26,385, c = 16,385 Å, β = 110,2° with four formula units in the cell. The final R value is 0,124. ClO anions are disordered. The reactions of [(tren)Co(O₂, tren)Co(tren)]⁴⁺ in aqueous solution are compared with those of [(tren) (NH₃) CoO₂Co (NH₃tren)]⁴⁺. In acidic solution the new complex mainly decomposes to Co^II and O₂. In alcaline medium the bridging tren is replaced by an OH bridge, forming the well characterized doubly bridged [(tren)-Co(O₂, OH)Co(tren)]³⁺. Differing from the singly bridged bis (ammino) complex, the reactions of which show no pH dependency at all, the decomposition of the tren bridged complex is H⁺-catalyzed. The kinetic data have been interpreted as (i) preceding fast protonation step which is followed by a conformational change of the bridging ring, (ii) acid hydrolysis of a Co-μ-tren bond and (iii) fast cleavage of the Co-OO bond which is labilized by coordinated H₂O.     

Über Alkalihexafluorobismutate(V)

The compounds LiBiF₆ (a = 5.18, c = 13.9₉ Å), NaBiF₆ (a = 5.47, c = 15.1₆ Å), RbBiF₆ (a = 7.71, c = 7.89 Å) and CsBiF₆ (a = 7.93, c = 8.27 Å, hexagonal lattice constants) are rhombohedral. The hexagonal unit cell contains three formula weights. LiBiF₆ and NaBiF₆ are isotypic with LiSbF₆, RbBiF₆ and CsBiF₆ are KOsF₆-isotypes. All compounds are colourless and very moisture sensitive.     

Über die Hydrolyse von Eisen(III)Salzlösungen. I. Die Hydrolyse der Lösungen von Eisen(III)chlorid

When a very diluted iron(III)chloride solution is slowly alkalified by a weak base, the deprotonation of [Fe(H₂O)₆]³⁺ proceeds in a first stage to form mono- and dinuclear hydroxoaquo-complexes. In a second stage 4 dimers condense around a chloride ion to form an eight membered ring, an embryon, which grows fast to very small crystals of the composition Fe₄O₃(OH)₅Cl and the structure of the β-FeOOH. These crystalline micells remain colloidally dissolved. If the pH is raised above approximately 3.4 the Cl^?- are exchanged against OH^?-ions and flocculation occurs. This shows that Pauli, assuming the micells of such sols to be polynuclear complex ions, is basically correct, and it follows that micells can also be micro-crystals. When an iron(III)chloride solution is neutralized fast with a strong base, an ‘amorphous’ precipitation is obtained which gives with MoK_α-X-rays only two broad reflections, showing that the iron oxide hydroxide octahedra are condensed in a highly disordered way. The coherently scattering areas of this precipitate are probably tetramers. Small amounts of primarily formed amorphous iron(III)hydroxide are transformed into β-FeOOH.     

Über Halogenphenylester der Phosphorsäure

A simple method for preparing halogenphenylesters of phosphoric, phenylphosphonic and phosphorous acid from the respective acid chlorides and phenols in the presence of various nitrogen-containing catalysts is described. Contrary to other methods, these reactions give high yields, despite of steric hindrance.