Cobalt -, chloride, monohydrate

Hydrate Isomerism.—As its name implies, this depends on the position of water in the molecule, just as in the case of the acido compounds. If two or more molecules of water are present in a molecule of ammine, the water may be present within the co-ordination complex or outside of it. For instance, the compound Cr en2.(H20)2.Br3 exists in isomeric forms. It may have all the water within the complex, in which case the formula will be [Cr en2(H20)2]Br3. In solution the whole of the bromine is precipitated by silver nitrate. On the other hand, the compound may have one molecule of water in the complex and the other outside, in which case the formula is [Cr en2(IT20)Br]Br2.H20, and only two-thirds of the bromine are precipitated by silver nitrate. Another example of this kind occurs in the cobalt series chloro-aquo-tetrammino-cobaltic chloride, [Co(NTI3)4Cl.H20]Cl2, is violet in colour, and is isomeric with dichloro-tetrammino-cobaltie chloride monohydrate, [Co(N1I3)4CI2]C1.H20, which is green. 

The acid chloride, [Co en2Cl2]Cl.HC1.2H20, is formed by mixing a solution of cobaltous chloride with an aqueous solution of ethylene-diamine monohydrate and oxidising the mixture with air. Concentrated hydrochloric acid is then added and the whole heated on a water-bath for one hour. The liquid is allowed to stand, when crystals separate, and are filtered and washed with concentrated hydrochloric acid.2 The salt crystallises in dark green rhombic plates. It is soluble in water, though less soluble than the normal salt, and on heating to 100° C. is transformed into the normal salt. 

Russian workers have reported some terpyridyl complexes of co-balt(III) 35), and the bis(terpyridyl) cobalt(II) ion is now known. The magnetic properties of Co(terpy) depend critically on the anion present in the crystal thus, at 20°C the magnetic moments are 4.3 (perchlorate), 2.7 (bromide dihydrate), 2.1 (chloride monohydrate), and 2.2 B. M. (aqueous solution). A study of the temperature dependence of the moment for Co(terpy)2Br2 2H20 indicated that no simple explanation was possible 379). The subject has been considered more recently by Judge and Baker 412a). Some peculiar bipyridyl derivatives of cobalt(II) cyanide were reported some years ago 571) these could warrant further investigation. The UV spectra of Co(II) and Co(III) complexes have also been measured. 

Procedure 5.1.b Bis(ethylenediamine)(oxalato)cobalt(lll) Chloride Monohydrate, [Co(en)2(ox)]CI H206... 

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). 

To a solution of 9.4 g (0.036 mole) of potassium c/s-diamminedicarbonato-cobaltate(III) in 20 mL of water is added 6 mL (0.072 mole) of pyridine. To the mixture, 60% perchloric acid is added dropwise in an ice bath to adjust the pH to 5.5. After filtration, the filtrate is stirred at room temperature for a while, whereupon pink crystals of c ,cu-diamminecarbonatodi(pyridine)cobalt(llI) perchlorate deposit. The product is collected on a filter, washed with water, and dissolved in water. The solution is poured into a column of Dowex 50W-X8 resin in the Na+ form in order to change the counter anion from perchlorate to chloride. The effluent obtained by elution with a 0.3 mole/L sodium chloride is concentrated to 10 mL under reduced pressure at 35°. The concentrated solution is filtered and kept in a refrigerator. Red crystals of m, ci s-diamminecarbonato-di(pyridine)cobalt(III) chloride monohydrate deposit. The crude product is re-crystallized from warm water at 35°. The crystals are collected on a filter, washed with cold water, ethanol, and diethyl ether, and finally dried under vacuum. The yield is 1.0 g. Anal. Calcd. for [Co(C03)(NH3)2(py)2]Cl-H20 C, 36.23 H, 4.98 N, 15.36. Found C, 36.07 H, 4.93 N, 15.55. 

Into a solution of 3.3 g (0.009 mole) of cis-diamminecarbonatodi-(pyridine)cobalt(III) chloride monohydrate in 10 mL of water is poured 1.2 g (0.0038 mole) of sodium (—, 2-ethanediamine-bis(oxalato)cobaltate(III) monohydrate3 with stirring. The solution is cooled in an ice bath, and the sides of the vessel are scratched with a glass rod, whereupon the diastereoisomeric salt of the (— )589 carbonato complex deposits. (If the diastereoisomer does not deposit, a small amount of ethanol is added.) The whole is kept in an ice bath for a while. The diastereoisomer is collected on a filter, washed with cold water, and recrystallized several times from water at 35° to increase the optical purity. The recrystallized salt is collected on a filter, washed with cold water, ethanol, and diethyl ether, and dried under vacuum. The yield is 0.3 g. Anal. Calcd. for [Co(C03)(NH3)2(py)2][Co(ox)2(en)]-2.5H20 C, 31.35 H, 4.49 N, 12.90. Found C, 31.37 H, 4.67 N, 12.82. The diastereoisomer is separated as before. 

Octahedral Chelate Complexes.— 2T-Ray analysis of (-l-) g,-c -dicyanobis-(ethylenediamine)cobalt(iii) chloride monohydrate establishes that the absolute configuration of the [Co(CN)2(en)J+ complex cation is a (AA), in conformity with the previous spectroscopic assignment. Both chelate rings are of the ob conformation. The mean Co-N and Co-C distances are 1.97 and 1.87 A, respectively and the Co-C-N units do not deviate significantly from linearity. In a preliminary note the absolute configurations of both complex ions in (—)6s -[Co(N02)2(en)J(+)68 -[Co(mal)jen], where mal = malonato, CHa(C08)2 , are said to be A and all en chelate rings to exhibit the ob conformation. ... 

CftH,8Cl3CoNftO, ciS Dichloro diethylenediamine cobalt(III) chloride monohydrate, 30B, 331... 

CsHi sClCoNsO, ( + )58g-Dicyanobis(ethylenediamine)cobalt(III) chloride monohydrate, 37B, 484... 

C6H2oClCoN60ft H2O, cis Dinitrobis(1,3-diaminopropane)cobalt(III) chloride monohydrate, 45B, 1151 C6H2oClCrNqOi,S2, Bis(2-mercaptoethylamine)ethylenediamine-chromiumdll) perchlorate, 42B, 718 C6H2oCl2CuN, 08, Bis(N-methylethylenediamine)copper (II) perchlorate, 35B, 677... 

C9H2 2BrClCoN90, cis-(Adeninato-chloro-bis(ethylenediamine)cobalt-dII)) bromide monohydrate, 40B, 810 C9H2 2C1CoNi,05, Ethylenediamine-N,N -diacetato- ((R) -1, 2-diaminopropane )cobalt (111) chloride monohydrate, 41B, 946 C9H2 2C1CoNi,07, cis-p-Carbonato- (3S, 8S-dimethyltr iethylenetetramine)-cobalt(III) perchlorate, 41B, 946... 

C9H32CI3C0N6O, (-)-Tris-(1,3-diaminopropane)cobalt(III) chloride monohydrate, 39B, 656... 

C8H20CI2C0N6OS2, Chlorobis(acetonethiosemicarbazone)cobalt(II) chloride monohydrate, 44B, 846... 

C8H22CIC0N6O5, Dinitro(1,4,7,10-tetraazacyclododecane)cobalt(III) chloride monohydrate, 40B, 884... 

Cl 5H2 7Cl2N9Ni08, TrihistaminenickeKlI) perchlorate, 38B, 922 Cl5H28CIC0N4O8, A-cis-j3-Oxalato(1,7-bis(2(S)-pyrrolidyl)-2,6-diaza-heptane)cobalt(III) perchlorate, 44B, 926 C15H4 4CI3C0N6O, Tris-(2,4-diaminopentane)cobalt(III) chloride monohydrate, 38B, 922... 

CsHigClCoNSe H2O, (Methyl dithiocarbazate-N, S)bis[methyl dithio-carbazato(1-)-N, S]cobalt(III) chloride monohydrate, 45B, 1287 CgHi eCl2CoNi,Sa 0.5 C3H8N2S2r Dichlorobis(methyl 2-methyldithio-carbazato-N, S)cobalt(II) methyl 2-methyldithiocarbazate solvate, 46B, 1204... 

Colloidal manganese arsenate may be obtained in an analogous way to that described for cadmium and cobalt arsenates.7 If concentrated solutions of manganous chloride and potassium dihydrogen arsenate are mixed at the ordinary temperature, a solid jelly is formed, which remains stable for weeks but finally, rose-coloured crystals separate and the jelly partly liquefies.8 The essential constituent of the jelly appears to be the monohydrogen arsenate, MnHAs04, and the crystals are the monohydrate, MnHAs04.Ha0. 

A stream of carbon dioxide is bubbled through a mixture of 133 ml. (1.64 moles) of ethylenediamine monohydrate and 133 ml. of water cooled in ice. The stream of carbon dioxide is maintained during the entire preparation. A solution of 195 g. (0.82 mole) of cobalt(II) chloride hexahydrate in 175 ml. of water at room temperature is added to the cold solution, which is continually stirred. The addition of the cobalt(II) salt causes a violent evolution of carbon dioxide gas, and the solution becomes red-violet. (Sometimes the mixture coagulates and becomes gel-like.) The cooling and the stirring are continued, and the mixture is oxidized by dropwise addition of 200 ml. of 30%... 

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