New Macrocyclic Ligands. XII. Phosphonic and Phosphinic Acid Pendant Arm Derivatives of Mixed Donor Macrocycles: Towards New Selective Reagents for Lead(II)

Abstract

The synthesis of new bis-phosphonic, -phosphinic and -phenylphosphinic acid pendant-arm derivatives of a 15-membered, N ₂ O ₂ -donor macrocyclic ring is described. Thermodynamic stabilities of the 1:1 (metal:ligand) complexes of cobalt(II), nickel(II), zinc(II), silver(I), cadmium(II) and lead(II) with the bisphenylphosphinic acid derivative have been determined in 95% methanol (I = 0.1, NEt₄ClO ₄; 25°C). Along the above metal-ion series, this ligand forms its most stable complex with lead(II).