The cobalt(III) complexes containing ammoniatriacetato group (ata) as a quadridentate ligand are newly prepared: i) α-K[Co ata(OH)(OH2)]·2H2O ii) β-K[Co ata(OH)(OH2)]·3H2O iii) K2[ataCo(OH)2Co ata]·6H2O iv) K2[Co ata(CO3)]·H2O v) K2[Co ata(C2O4)]·H2O In order to determine the structural formulae of these complexes, their visible, ultraviolet and infrared spectra were measured, as well as their thermal decomposition and their potency to coagulate ferric oxide sol.
Reaction of hydrogen peroxide with titanium(IV) has been investigated over the range of pH 0 to 13. Below pH 2 this reaction gives orange-colored ion-species, [Ti(OH)2(H2O)(H2O2)]2+ or (TiO2·-aq)2+. In the range of pH 3 to 6 formation of a yellow species is observed and its chemical formula is presumed to be [Ti(OH)3(H2O2)]+. Existence of a species different from the above is indicated by the pale yellow color observed in the region of pH 7 to 9. This species is very unstable unless a large excess of hydrogen peroxide is present, and its chemical formula is presumed to be [Ti(OH)3(OOH)]0. At higher pH values (10<pH), the reaction mixture is colorless, and presumably contains [Ti(OH)2(O2)2]2−. All the tentative formulae of these species are based on the composition of isolated salts, the absorption spectra of the solutions etc. A solution containing [Ti(OH)2(H2O)(H2O2)]2+ remains unchanged but a solution containing [Ti(OH)3(H2O2)]+ gives a yellow precipitate TiO(OH)(OOH), and one containing [Ti(OH)3(OOH)]0 or [Ti(OH)2(O2)2]2− gives a pale yellow compound (Remark: Graphics omitted.) at room temperature or more quickly when heated on a water-bath. The precipitation reaction of (Remark: Graphics omitted.) is taken advantage of in a new volumetric analysis suited for determination of titanium in quantities of the order of 10 mg.
A green compound is isolated from the concentrated solution obtained by the action of hydrogen peroxide on cobalt (II) ions in the presence of potassium bicarbonate, and the formula K3[Co(CO3)3]·3H2O is assigned to it on the basis of the analysis of the solid and of the absorption spectrum of the solution. A series of ammine-carbonatocobalt (III) complexes, K3[Co(CO3)3]·3H2O, blue (perhaps, cis) and violet(perhaps, trans)-K[Co(NH3)2(CO3)2]·H2O, [Co(NH3)4CO3]Cl and [Co(NH3)6]Cl3, are synthesized from the abovementioned green solution by means of successive substitution of carbonate ions by ammonia groups. Hexamminecobalt (III) tricarbonatocobaltate, [Co(NH3)6] [Co(CO3)3], is also obtained by adding a hexamminecobalt (III) salt to the green solution of tricarbonato-complex. Three complexes, K3[Co(CO3)3]·3H2O and blue- and violet-K[Co(NH3)2(CO3)2]·H2O, are probably to be regarded as new complexes and may be identified by their absorption spectra.
The four new complexes of the mixed cyanoammine and -diamine series cis-and írares-Co(CN)2(NH3)4+, i;'a»s-Co(CN)2(en)2+, and »er-Co(CN)sdien were prepared and characterized by visible and ultraviolet absorption spectra as well as infrared spectra.In addition, the known complexes, ?»er-Co(CN)3(NH3)3, m-Co(CN)2(en)2+, and Co CN(NH3)52 + have also been prepared. All of these complexes were synthesized by the reaction of potassium cyanide with Co(NH3)e3+, Co(en)33+, or Co-(dien)23 + in the presence of activated charcoal at low temperature (0-5°). Experimental SectionPreparation. (1) dx-Dicyanotetraamminecobalt (III) Chloride Monohydrate, fro?zi-Dicyanotetraamminecobalt(III) Chloride, and mer-Tricyanotriamminecobalt(III):cis-[Co(CN)2-(NH3)4]C1-H20, trans-[Co (CN )2(NH3)4] Cl, and 4»er-Co(CN)"-(NH3)3.-To a cold solution (ca. 0°) of 17 g (0.05 mol) of [Co-(NH3)6](02CCH3)3 in 200 ml of water, 10 g (0.15 mol) of potassium cyanide in 50 ml of cold water was added dropwise with stirring. Two grams of activated charcoal was added to the above solution, and the mixture was kept in a refrigerator for 1 week without stirring (or 3-4 days with stirring). After that, the reaction mixture was filtered, and the filtrate was diluted to 600 ml with water.About 150 ml of this solution was poured into a(1) P.
The cobalt (III) complexes containing ammoniadiacetate group (ada) and ethylene diaminediacetate group (edda) have been prepared: 1) K[Co(ada)2]·4H2O Red-violet 2) K[Co(edda)(CO3)]·H2O Red-violet 3) [Co(edda)(OH2)2]ClO4 Violet 4) K[Co(edda)(NO2)2]·H2O Yellow-brown The visible and the ultraviolet absorption spectra as well as the infrared spectra of these complexes have been measured and discussed in relation to the structures of these complex ions.
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