Dichlorobis ethylenediamine cobalt III Chloride

The traditional method of isolating the trans-dichlorobis-(ethylenediamine)cobalt(III) chloride salt by evaporation of the reaction mixture to dryness in the steam bath gives some reduction to cobalt(II). To avoid this, the chloride salt in the following procedure is isolated by saturation of the reaction mixture with hydrogen chloride gas and by precipitation with standing at room temperature. As an alternative method, the reaction mixture from the preparation of (carbonato)bis(ethylene-diamine)cobalt(III) chloride can be used as the starting material. 

Preparation from (Carbonato)bis(ethylenediainine)cobalt(III) Chloride 

To one-fifth of solution A (0.164 mole of cobalt(II) salt, see preparation A) is added 60 ml. of ice-cold 12 M hydrochloric acid. The solution is filtered, cooled to a temperature of 5-10°C., and saturated with hydrogen chloride gas as above. The trans-dichloro salt is isolated as before. The yield is 35.1 g. (75% based upon cobalt(II) chloride). Anal. Found Co, 20.61 N, 19.66 C, 16.89 Cl, 37.25 H, 5.57. 

---

Lithium tetranitrodiamminecobaltate(III) Trans-dichlorobis(ethylenediamine)cobalt(III) chloride... 

Besides (carbonato)bis(ethylenediamine)cobalt(III) chloride and the corresponding bromide salt, the following complexes are described cis- and frara -dichlorobis(ethylenediamine)cobalt(III) chloride, cts-aquachlorobis(ethylenediamine)cobalt(III) sulfate, cis-bis(ethylenediamine)dinitrocobalt(III) nitrite, m-aquabis-(ethylenediamine)hydroxocobalt(III) dithionate, and cis-diaqua-bis(ethylenediamine)cobalt(III) bromide. 

To 27.5 g. (0.1 mole) of crude (carbonato)bis(ethylenediamine)-cobalt(III) chloride is added 200 ml. of 1.00 N hydrochloric acid. The carbonato complex is dissolved with evolution of carbon dioxide gas and formation of a red solution consisting primarily of the corresponding cw-diaqua species. The solution is evaporated in the steam bath until an almost dry paste has been formed. The purple residue is filtered and washed with three 20-ml. portions of ice-cold water. Drying in air yields 19.5 g. of purple crystals of cu-dichlorobis(ethylenediamine)cobalt(III) chloride. The mother liquor and the washings are again evaporated almost to dryness to yield a second crop of crystals, 5.9 g. The total yield is 25.4 g. (84% based on (carbonato)bis(ethylenediamine)cobalt(III) chloride). The analysis and the visible absorption spectrum of the two fractions are identical. Anal. Calcd. for [Co(en)2Cl2 ] C1 H20 Co, 19.42 N, 18.46 C, 15.82 Cl, 35.05 H, 5.98. Found Co, 19.50 N, 18.57 C, 15.77 C1, 35.15 H, 6.01. 

C7H28CI3C0N10S3, trans-Dichlorobis(ethylenediamine)cobalt III) chloride - tris(thiourea), 39B, 440 C8H6K3M0N6O3S6 r Potassium hexaisothiocyanatomolybdate(lII) hydrate-acetic acid, 33B, 422... 

Cl2Ni,Pd, Bis(ethylenediamine)palladium(II) chloride, 31B, 375 C Hi gClaCoNi, trans-Dichlorobis(ethylenediamine)cobalt (III) chloride, 23, 572... 

Disodium cw-bis(ethylenediamine)disuIfitocobaltate(III) nitrate and also the perchlorate have not been reported before and are recommended as sources of the cfs-bis(ethylenediamine)disulfito-cobaltate(III) ion, which has been prepared by Baldwin1 by proceeding through a difficult series of complex salts. The m-azidobis(ethylenediamine)sulfitocobalt(III) is also newly reported it can be converted into a relatively pure sodium ran.y-bis(ethylenediamine)disulfitocobaltate(III), which has previously been made from dichlorobis(ethylenediamine)cobalt(III) chloride1 and tetraammine(carbonato)cobalt(III) chloride.2... 

For the dichlorobis(ethylenediamine)cobalt(III) ion, [Co(en)2Cl2]+, two geometrical isomers, cis and trans, are possible. As was described in Chapter 2, a plane of symmetry (mirror plane) divides a molecule into equal fragments. For the trans isomer (shown in Figure 19.1), there is a plane of symmetry that bisects the cobalt ion and the ethylenediamine ligands with one chloride ion on either side. As shown in Figure 19.1, the cis isomer has no plane of symmetry. 

C4H21CI4C0N4O2, trans Dichlorobis(ethylenediamine)cobalt(III) hydrochloride dihydrate, 16, 457 42B, 717 C4H2iCl4CrN402, trans-Dichlorobis(ethylenediamine)chromium(lll) chloride hydrochloride dihydrate, 24, 596 C4H2 aClCoNeOeSa, Tris(ammine)diethylenetriaminecobalt(111) chloride dithionate, 44B, 797... 

Several preparations of salts of the czs-dinitrobis(ethyl-enediamine)cobalt(III) ion have been reported in the literature. The most usual is that of Werner/ modified by Holtzclaw, Sheetz, and McCarty, beginning with potassium hexanitrocobaltate(III). However, this method makes use of a starting material which is difficult to prepare in high purity and to dry thoroughly, involves critical temperature control, and produces a yield of about 15%. The following procedure, which utilizes ethylenedi-amine)cobalt(III) chloride as the starting material, provides a 60% yield of cfs-dinitrobis(ethylenediamine)cobalt-(III) nitrite. The nitrite is then easily converted to the nitrate. 

Write formulas for the following compounds, using brackets to enclose the complex ion portion (a) tri-amminebromoplatinum(II) nitrate (h) dichlorobis(ethylenediamine)cobalt(Il) monohydrate, (c) penta-amminesulfatocobalt(III) bromide, (d) potassium hexafluoroplatinate(IV), (e) tetraaquadibromochro-mium(lll) chloride, (/) ammonium heptafluorozirconate(lV). 

C6H24NeNi06, Trisethylenediaminenickel nitrate, 24, 605 C6H25ClaCoN202, trans-Dichlorobis(l-propylenediamine)cobalt(III) chloride hydrochloride dihydrate, 27, 833 CgH26AU2N6O12S4, Ethylenediammonium bis-cis-(ethylenediamine-disulf itoauratedll)), 41B, 941... 

---