ABSTRACT.A new N4O3 heptadentate ligand, N,N'-Bis(2-hydroxybenzyl)-1,3-bis[(2-aminoethyl)amino]-2-propanol(H-BAP· 4HCl)was synthesized. The hydrochloric acid salts of Br-BAP·4HCl, Cl-BAP·4HCl, CH3O-BAP·4HCl and CH3-BAP·4HCl containing Br-, Cl-, H-, CH3O-and CH3-groups at the para-site of the phenol group of the H-BAP were synthesized. The structures of the ligands were confirmed by C. H. N. atomic analysis and 1 H NMR, 13 C NMR, UV-visible and mass spectra. The elemental stepwise protonation constants(logKn H ) of the synthesized N4O3 ligands showed six steps of the proton dissociation. The orders of the overall dissociation constants(logβp) of the ligands were Br-BAP < Cl-BAP < H-BAP < CH3O-BAP < CH3-BAP. The orders agreed well with that of Hammett substituent constants(σp). The calculated stability constants(logKML) between the ligands and transition metal ions agreed well with the order of the overall proton dissociation constants of the ligands but they showed a reverse order in Hammestt substituent constants(σp). The order of the stability constants between the transition metal ions with the ligands were Co(II) < Ni(II) < Cu(II) > Zn(II) > Cd(II) > Pb(II).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.