ABSTRACT
This chapter discusses the metal ion chemistry of a selection of mixed donor crowns with a number of heavy metal ions. Based on donor atom type, macrocyclic ligands can be divided into two extreme categories. The first category incorporates donor atoms such as nitrogen, sulfur, arsenic, or phosphorus. The polyether crowns, with their especial affinity for alkali and alkaline earth ions, constitute the second group. The series of S2N2 macrocycles (9)—(14), incorporating cis and trans arrangements of the heteroatoms, has been synthesized by high dilution techniques and their Cu(II) complexes have been isolated. The nickel chloride complex of the trans-S2N2 macrocycle has been shown by x-ray diffraction to be octahedral, with the chloro groups in cis positions and the remaining positions being occupied by the macrocyclic ligand donors. The effect on metal coordination of the chiralities of the donor phosphorus groups as well as of the nature of the second donor groups present has been investigated.
