Synthesis of 1, 10-phenanthroline tetradentate diamines and potentiometric determination of the formation constants of their complexes with manganese(II), cobalt(II), copper(II) and zinc(II)

Abstract

Six tetradentate ligands incorporating 1, 10-phenanthroline and two alkyl amino donors have been prepared. The structure of these ligands has been studied by elemental analysis, IR and ¹H NMR. N,N'-diisopropyl - 1, 10-phenanthroline -2,9-dimethanamine has been analyzed by X-ray diffraction. The crystal of

C₂₀H₂₈N₄. 1. 8(NO₃)-0.2(OH)-2(H₂O) is monoclinic, space group P2 _l/<i>c</i> , (<i>a</i>=7.6 12(2), <i>b</i>=15.182 (3), <i>c</i>=20.551 (4)Å, β=91.16(3)^o, z=4<i>, R </i>= 0.060,<i> R_w=</i>0.062)<i>. </i>The protonation constants and the formation constant s of complexes with dipositive ion(Mn²⁺, Co²⁺,Cu²⁺ and Zn²⁺) have been determined in aqueous solution by <i>p</i>H metric method. Steric effects and electron inductive effects on the stability of complexes have been discussed.