Pendant‐armed Unsymmetrical Aza‐macrocycles: Syntheses, Coordination Behavior and Crystal Structure of a Dinuclear Cadmium Complex

Two unsymmetrical tetradentate aza ‐macrocycles with side arms attached to the N sp 3 atoms, L 1 and L 2 , as well as their complexes with different metal cations were synthesized and characterized by EA, UV, IR, 1 H NMR and MS spectra. Both the two ligands can efficiently transport alkali and transition metal cations across an organic membrane with high selectivity ratio. The structure of a dinuclear Cd (II) complex [L 1 ] · (Cd‐Cl 2 ) 2 was elucidated by X‐ray crystallography and was solved by the heavy‐atom method to a final R value of 0.029 for 3084 reflections with | F| > 3σ ( I ). In the exo‐structure of the dinuclear complex each cadmium atom is five‐coordinated, bonding to three N atoms and two chlorine atoms.