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Sterisch behinderte Metallkomplexbildung bei den Kondensationsprodukten von cis‐ und trans‐1,2‐Diaminocyclohexan mit Acetylaceton
Author(s) -
Honda Masatake,
Schwarzenbach G.
Publication year - 1957
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.19570400104
Subject(s) - chemistry , steric effects , acetylacetone , metal , ethylenediamine , spectrochemical series , ligand (biochemistry) , stability constants of complexes , chelation , stereochemistry , medicinal chemistry , polymer chemistry , crystallography , ligand field theory , inorganic chemistry , organic chemistry , ion , receptor , biochemistry
Due to increasing steric hindrance, the stability of the metal complexes of ethylenediamine‐bis‐acetylacetone (AeDAA) and the two stereoisomeric forms of 1,2‐diaminocyclohexane‐bis‐acetylacetone (DCAA) decreases in the following series: M(AeDAA) > M(cis‐DCAA) > M(trans‐DCAA). A Co II ‐complex can only be prepared with AeDAA; Ni II and Cu II form complexes with AeDAA and cis‐DCAA but not with trans‐DCAA and of Pd II and Pt II complexes could be prepared with all three complexing agents. These facts agree with decreasing stability of the complexes in the metal‐series Pt, Pd > Cu > Ni > Co. The apparent stability constant of the complex Cu(AeDAA) has been evaluated. The striking difference in colour between Cu(AeDAA), purple, and Cu(cis‐DCAA), green, is explained by the difference in symmetry of the ligand field in the two complexes.