Effects of Ligand Chain Length and Terminal N‐Alkylation on the Protonation Constants and Stability Constants of Some Transition Metal Complexes of Linear Tetraaza and Pentaaza Ligands

Abstract

AbstractA number of terminal N‐alkylated linear tetraaza and pentaaza ligands were prepared. Their ligand protonation constants and some transition and post‐transition metal (Ni2+, Cu2+, Zn2+, and Cd2+) complex stability constants were determined by potentiometric titration methods. In general, methylation and ethylation at the terminal nitrogen atoms caused the corresponding ligand nitrogen basicity to increase; however, the corresponding metal complex stabilities were decreased compared to the non‐alkylated structural analogs, presumably due to a steric effect.