β β' β"-Triaminotriethylamine and its complex metallic compounds

We have recently shown (‘Roy. Soc. Proc.,’ A, 1924, vol. 107, p. 80) that 1:2:3-triaminopropane forms co-ordination compounds with certain trivalent metals, such as cobalt and rhodium; these compounds are of the general type ofbis -propanetriamine cobaltic chloride, [Co 2(NH2 .CH(CH2 .NH2 )2 )] Cl3 , in accordance with Werner’s theory of co-ordination. In these compounds the triaminopropane behaves in a similar way to ethylenediamine, each amino-group taking part in the formation of the co-ordinated radicle. It is thus seen that the grouping, NH2 .CH2 .CH.NH2 , which is present twice in the triamino- propane molecule, behaves for co-ordination purposes in the same way as the molecule of ethylenediamine, NH2 .CH2 .CH2 .NH2 . This analogy in behaviour appears worthy of further investigation, and we have therefore studied the manner in which β β' β"-triaminotriethylamine, N(CH2 .CH2 .NH2 )3 , co-ordinates with the metals; in this substance the grouping, NH2 .CH2 .CH2 .N:, occurs three times, but it would seem that the presence of the three primary amino-groups has greatly diminished the basic properties of the tertiary amino-radicle, since Ristenpart (‘Ber.,’ 1896, vol. 29, p. 2530) obtained only salts in which the substance acts as a tribasic amine. It might thus be anticipated that co-ordinated salts of the type I would be formed.