Stabilization of monovalent nickel in aqueous solutions by a saturated tetra-aza-macrocyclic ligand

Abstract

The planar form of the complex C-meso-1,4,5,7,7,8,11,12,14,14-decamethyl-1,4,8,11-tetra-azacyclotetradecanenickel(I){[Ni(L¹)]⁺}is shown to be stable in aqueous solutions, with t_½ > 100 h and the formal potential of the couple [Ni(L¹)]²⁺/[Ni(L¹)]⁺ is – 0.98 V vs. standard calomel electrode; redox reactions involving this couple were studied and compared with those of the couple [Ni(L²)]²⁺/[Ni(L²)]⁺(L²=C-meso-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetra-azacyclotetradecane).