Steroids as Chiral Ligands: Different Molecular and Crystal Structures of Copper(II) Complexes of Mono‐ and Dideprotonated 16β‐Salicylideneimino‐17β‐hydroxy‐3‐methoxyestra‐1,3,5(10)‐triene

The steroidal 16β‐salicylideneimino‐17β‐hydroxy compound 1 , synthesized from the corresponding 16β, 17β‐amino alcohol, served as a new tridentate chiral ligand for Cu 2+ ‐complexation. The X‐ray data for 1 and for two dimeric copper complexes 2 and 3 are presented and discussed. Using copper(II) acetate for complexation, dideprotonation of 1 is observed. The neutral complex 2 obtained is characterized by a central planar four‐membered copper—oxygen ring. The cycloaliphatic 17β‐oxygen anions are bridging atoms; the copper ions are tetracoordinated. Reaction of 1 with copper(II) perchlorate gave only monodeprotonation of the phenolic groups. These oxygen anions are now the bridging atoms; furthermore the two copper ions are bridged by a perchlorate anion. Thus the central four‐membered ring is folded (22°), and the copper ions are hexacoordinated (binding of a molecule of water). The crystal lattices of 2 and 3 are also quite different.