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 of
bis
-propanetriamine cobaltic chloride, [Co 2(NH
2
.CH(CH
2
.NH
2
)
2
)] Cl
3
, 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, NH
2
.CH
2
.CH.NH
2
, which is present twice in the triamino- propane molecule, behaves for co-ordination purposes in the same way as the molecule of ethylenediamine, NH
2
.CH
2
.CH
2
.NH
2
. This analogy in behaviour appears worthy of further investigation, and we have therefore studied the manner in which β β' β"-triaminotriethylamine, N(CH
2
.CH
2
.NH
2
)
3
, co-ordinates with the metals; in this substance the grouping, NH
2
.CH
2
.CH
2
.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.
Explicit birational geometry of threefolds of general type, I