Sterisch behinderte Metallkomplexbildung bei den Kondensationsprodukten von cis‐ und trans‐1,2‐Diaminocyclohexan mit Acetylaceton

Abstract

Abstract 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.