Self-assembling chiral metallo-clefts; synthesis and molecular structure of N,N'-bis(12H-benzo[a]xanthen-12-ylidene)-1,2-ethanediamine zinc(II)-dichloride complex

Bulky ligands for cleft-type metal complexes were synthesized from thio ketones and diamines in yields varying from 20–80%. A molecular structure determination of one ligand N,N'-bis(12H-benzo[a]-xanthen-12-ylidene)-1,2-propanediamine (19) was performed. A metallocleft was constructed by a self-assembling process with zinc(II) chloride. A crystallographic study of this zinc complex (24) revealed surprisingly that an anti–syn inversion of the imine moieties of the ligand had taken place during complexation.