치환기를 가진 다섯 자리 질소-산소 (N2O3)계 리간드의 합성 및 전이금속(II) 이온과의 착물 안정도상수 결정

Abstract

Hydrochloric acid salt of a new <TEX>$N_2O_3$</TEX> pentadentate ligand, N,N'-Bis(2-Hydroxybenzyl)-1,3-diamino-2-propanol(H-BHDP 2HCl) was synthesized. Br-BHDP 2HCl, CI-BHDP 2HCl, <TEX>$CH_3-BHDP$</TEX> 2HCl and <TEX>$CH_3O$</TEX>-BHDP 2HCl having Br, Cl, <TEX>$CH_3$</TEX> and <TEX>$CH_3O$</TEX> substituents at 5-position of the phenol group of H-BHDP 2HCl were also synthesized. The potentiometry study in aqueous solution revealed that the proton dissociations of the synthesized ligands occurred in four steps and their order of the calculated overall proton dissociation constants(<TEX>$log{\beta}_p$</TEX>) was Br-BHDP < Cl-BHDP < H-BHDP < <TEX>$CH_3O-BHDP$</TEX> < <TEX>$CH_3-BHDP$</TEX>. The order showed a similar trend to that of Hammett substituent constants(<TEX>${\delta}_p$</TEX>). The order of the stability constants(<TEX>$logK_{ML}$</TEX>) was Co(II) < Ni(II) < Cu(II) < Zn(II) < Cd(II) < Pb(II). The order in their stability constants (<TEX>$logK_{ML}$</TEX>) of each transition metal complex agreed with that of the overall proton dissociation constants (<TEX>$log{\beta}_p$</TEX>).