Complexes of cis-a Series

The corresponding cw-a-dinitro bromide, nitrate and acetate are prepared in a similar manner by using the respective cobalt(II) salts and acids. The analogous preparation of perchlorate complex gives a mixture of cis i and cij-p isomers, with reversed order of solubilities. 

According to Basolo, aerating a mixture of trien and C0CI2, adding 10 mol/dm HCl and evaporating the solution, Sargeson and Searle obtained a crude product which was blue rather than violet and finally obtained pure cis-a dichloro chloride after repeated recrystallizations from boiling 3 mol/dm HCl. 

CiJ-a-[Co(C03)(trien)] CIO4 H2O. Pure cis-a dichloro complex is added to a large volume of 0.013 mol/dm HCIO4 and the solution is stirred until the dichloro chloride is dissolved and aquated to the aquachloro stage (more than one day). Then, excess NaHC03 and NaC104 are successively added. When the mixture is evaporated at room temperature, the perchlorate monohydrate crystallizes out. 

C -P-[Co(C03)(trien)] Cl 1.5 H2O. Treatment of c/s-a-[CoCl2(trien)] Cl with COf in baric solution produces the cis-p carbonate complex a mixture of crude cis-a dichloro chloride and Li2C03 in water is heated with stirring, whereupon the violet 

In order to distinguish a- and P-carbonato complexes, absorption spectral data are useful (Fig. 1.3). 

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