Cobalt complexes biguanide

The bivalent metals, as usual, combine with two molecules of biguanide to form 4-coordinated planar complexes, while the trivalent cobalt and chromium combine with three molecules of the ligand to produce a 6-coordinated octahedral configuration. The only exception is the trivalent silver which yields, however, a 4-coordinated planar complex. The preparation of the free tris(biguanidato) chromium, Cr(C2N5H6)s, in the anhydrous state,6 as well as of the corresponding anhydrous cobalt(III),8 copper(II), cobalt(II), palladium(II), and nickel(II) compounds, provides indisputable evidence for the structure proposed. Similar anhydrous metallic complexes with numerous substituted biguanides also have been included in the above-mentioned studies. 

Phenylbiguanide, C6H6NHC(NH)NHC(NH)NH2, combines with trivalent cobalt, as does biguanide itself, to form complex tris(phenylbiguanido) cobalt (III), its hydroxide, and tris(phenylbiguanide)cobalt salts.1 All of these resem-... 

Extensive work has been carried out on the resolution of optically active biguanide complexes and specific mention may be made in this connection of the contributions on the resolution and crystal structure of tris(biguanide)cobalt(III) chloride. 

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