Tris ethylenediamine cobalt III Chloride

Sixty-one grams of 30 per cent ethylenediamine is partly neutralized with 17 ml. of 6 hydrochloric acid and the 

Inorganic Syntheses, Volume II Edited by W Conard Femelius 1946 by McGraw-Hill Book Company, Inc. 

Tris(ethylenediamine) cobalt (III) chloride crystallizes in orange-yellow needles, which are readily soluble in water but insoluble in the usual organic solvents. Its solubility in 6 A hydrochloric acid is about 3 per cent. It is stable at temperatures as high, as 200° and is decomposed only slowly by hydrogen sulfide and sodium hydroxide. 

CIS- AND riJAiVS-DICHLOROBIS-(ETHYLENEDIAMINE)COBALT(in) CHLORIDE AND THE RESOLUTION OF THE CIS FORM 

Submitted by John C. Bailar, Jr. Checked by Carl L. RoLUNSONt 

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The following procedure is based on the reaction of an aqueous solution of cobalt(II) chloride with the equivalent amount of (2-aminoethyl)carbamic acid, followed by oxidation with hydrogen peroxide and the subsequent formation of bis(ethylene-diamine)cobalt(III) ions. The bis(ethylenediamine)cobalt(lII) species are converted to the carbonato complex by reaction with lithium hydroxide and carbon dioxide. During the entire preparation a vigorous stream of carbon dioxide is bubbled through the reaction mixture. This procedure appears to be essential in order to minimize the formation of tris(ethylenediamine)cobalt(III) chloride as a by-product. However, the formation of a negligible amount of the tris salt cannot be avoided. The crude salts have a purity suitable for preparative purposes. The pure salts are obtained by recrystallization from aqueous solution. 

Tris (ethylenediamine) cobalt (III) chloride was first prepared by Werner.1 Resolution was effected through the chloride d-tartrate which was obtained by allowing the chloride (1 mol) to react with silver d-tartrate (1 mol). The correct ratio of chloride ion to tartrate ion is important and this has meant that it was necessary to isolate the pure solid chloride, the synthesis of which has been described by Work.2 In the present method the less soluble diastereo-isomer is isolated directly and the expensive and unstable silver d-tartrate is replaced by barium d-tartrate. The addition of activated carbon ensures rapid oxidation of the initial cobalt (II) complex and eliminates small amounts of by-products of the reaction. 

Levo iodide. The Zeyo-tris(ethylenediamine) cobalt (III) chloride d-tartrate remaining in the solution above is treated with concentrated ammonia solution (0.5 ml.) and the mixture is heated to about 80°. Solid sodium iodide (35 g.) is stirred in and the whole cooled in ice. The impure levo iodide is filtered off and washed with ice-cold 30% sodium iodide (25 ml.) and then with alcohol and air-dried, resulting in a yield of 27 g. Purification is effected by stirring the whole of the crude material into 65 ml. of water heated to 50°. The racemate remains undissolved and is filtered off. Sodium iodide (10 g.) is added to the warm filtrate (50°) and crystallization allowed to take place. After cooling in ice the solid is filtered, washed with ethanol and then acetone, and air-dried. The yield is 18 g. (26%), and [a]D = -90°. Anal. Calcd. for [Co(en)3]I3-H20 C, 11.26 H, 4.11. Found C, 11.43 H, 4.01. 

Busch and Bailar1 obtained optically active solutions of one of the enantiomers of the ethylenediaminetetraacetato-cobaltate(III) ion by selective adsorption on optically active quartz and by fractional crystallization of the strychnine salt. More recently Dwyer, Gyarfas, and Mellor2 reported the complete resolution using d and Z-tris(ethylenediamine) cobalt(III) chloride. Precipitation of the diastereoisomers was effected by addition of ethanol to the aqueous solution. The volume of ethanol used was critical and often merely the potassium salt separated. 

Chloropentaamminecobalt(III) chloride forms red-violet rhomb-shaped crystals which decompose on heating above 150° with the stepwise loss of ammonia. The solubility of the salt in water at 25° is 0.4 g./lOO ml. The compound readily aquates in hot water, forming the aquopentaammine chloride. Chloropentaamminecobalt(III) chloride reacts with hot aqueous ethylenediamine or dZ-propylenediamine to form tris (ethylenediamine) cobalt (III) chloride or the corresponding propylenediamine compound, with liberation of ammonia. Concentrated sulfuric acid at room temperature produces a complex hydrogen sulfate of the chloro-pentaamminecobalt(III) ion. Aqueous mercury(II) chloride forms a characteristic precipitate of a double salt, [Co(NH3)6Cl]Cl2-3HgCl2, suitable for microchemical identification. Complete physical and chemical data may be found in Gmelin s handbook. ... 

The second piece of work I wish to mention is a quite different sort, involving attempts to achieve the optical resolution of tris-ethylenediamine cobalt(III) chloride, [CoensJCls, by bacterial action. Many chemists have studied the physiological action of metal complexes, and Dwyer and his... 

Co(en)2(N02)2]N03 cis- and trans-Dinitrobis(ethylenediamine)co-balt(III) nitrate, 4 176, 177 [Co(en)3]Cl3 Tris(ethylenediamine)-cobalt(III) chloride, 2 221 CoF3 Cobalt(III) fluoride, 3 175 [Co NH(C5H4N)21C12] Dichloro-(di-2-pyridylamine)cobalt (II), 6 184... 

Co(en)a]ClCiH306-5H20 Tris-(ethylenediamine)cobalt (III) chloride dea tro-tartrate,... 

Tris(ethylenediamine)cobalt(III) chloride Tris(l,3-diamino-2-propanol>x>balt(III) nitrate Tris(acetylacetonato)cobalt(III)... 

CgH2aCdN603S2f Trisethylenediaminecadmium thiosulfate, 40B, 1111 CeH2 i,Cl2CuN6 0.75 C2H8N2, Tr is (1, 2-diaminoethane )copper (11) chloride 1,2-diaminoethane solvate, 45B, 1017 CsH2 ci3CoNg 2.8 HjO, DL-Tris(ethylenediamine)cobalt(III) chloride hydrate, 41B, 940... 

CgH2gClaCoNgO, ( + )-D-Tris(ethylenediamine)cobalt(III) chloride monohydrate, 34B, 485... 

C6H30CI3C0N6O3, D-Tris-(ethylenediamine)cobalt(III) chloride trihydrate, 20, 503... 

Cl2HsoCl6CoCrNi20s, (+) Tris(ethylenediamine)cobalt(III) (-) tris-(ethylenediamine)chromium(III) chloride hydrate, 42B, 729 Cl2H6oCl6CrNi20gRh, (+) Tris(ethylenediamine)chromium(III) (+)-tris-(ethylenediamine)rhodium(III) chloride hydrate, 42B, 729 Cl2H60CI7CO2N12NaOg, Sodium D-tris(ethylenediamine)cobalt(III) chloride hexahydrate, 19, 539 21, 547 Cl2H60CI7CO2N12NaOfi, Sodium L-tris-(ethylenediamine)cobalt(111) chloride hexahydrate, 19, 539... 

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