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Polyamines XV. Thermodynamics of Metal Complex Formation of Linear Tetraamines Containing Two Ethylenediamine Residues
Author(s) -
Anderegg Giorgio,
Bläuenstein Peter
Publication year - 1982
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19820650324
Subject(s) - chemistry , ethylenediamine , enthalpy , standard enthalpy of formation , steric effects , complex formation , stability constants of complexes , metal , stereochemistry , steric factor , standard enthalpy change of formation , crystallography , thermodynamics , inorganic chemistry , aqueous solution , organic chemistry , physics
The complex formation of Co 2+ , Ni 2+ , Cu 2+ , Zn 2+ , Pb 2+ and Hg 2+ with three tetraamines of type H 2 N(CH 2 ) 2 NH(CH 2 ) n NH(CH 2 ) 2 NH 2 (= 2, n, 2‐tet) for n = 2. 3 and 4, and with N ‐methylethylenediamine (= nmen) have been investigated at 25° and I = 1(KNQ 3 ). The stability constants and the heat evolved by formation of the (1:1)‐complexes ML have been determined. It is shown that the more stable complexes are normally formed by 2,3,2‐tet‐ligands. These results are discussed relating the thermodynamic data obtained to the stereochemistry of the complexes and using the visible spectra of the complexes in solution. The change in enthalpy is found to be the dominant factor and the measure of the steric strain whereas the entropy of complex formation decreases slowly.