Metallkomplexe mit Polyaminen X: Mit Tetrakis‐(β‐aminoäthyl)‐äthylendiamin =„penten„

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Abstract
N, N, N', N'‐Tetrakis‐(, 5‐aminoethyl)‐ethylendiamine7 abbreviated with „penten”︁, which contains 6 basic nitrogen atoms, forms metal complexes of a very high stability. The stability constants of Mn(penten)+2, Fe(penten) +2, Co( penten)+ 2, Ni( penten)+ 2, Cu( penten)+2, Zn( penten)+2, Cd(penten)+2 and Hg(penten)+2 have been determined. In the complexes of Mn, Fe, Co, Ni and Cd „penten”︁ functions doubtless as a hexa‐dentate group. In spite of this fact, the complexes of these metals add protons rather easily, forming hydrogen complexes MHpenten+3. This is probably due to some strain within the 5 condensed chelate rings. Protons are still more easily added by the complexes of Cu, Zn and Hg, where the hexamine „penten”︁ functions probably as a tetradentate or a pentadentate group only. Cu(penten)+2 and Hg(penten)+2 can even add two protons each, forming CuH+2penten+4 and HgH+2penten+4. Some evidence is given for the existence of CuH3penten+5, CoH3,‐penten+5, NiH2 penten+4, CdH3penten+5 and HgH3penten+5.