Synthesis, characterization and thermodynamic study of a novel N-functionalized macrocycle and its metal complexes

摘要

A new N-carboxymethyl derivative of the tetraazamacrocyclic ligand LH_4 (5,7,12,14-tetramethyl-1,4,8,11-tetraazamacrocyclotetradecane-N,N',N",N'"-tetraacetic acid) and its complexes with Cu~(2+), Co~(2+), Ni~(2+), UO~(2+) and Th~(4+) have been synthesized and characterized by elemental analyses, UV, IR, ~1H NMR spectra and X-ray powder diffraction. The stability constants of mononuclear complexes of LH_4 with the ions above were determined at 35 +- 0.1, 45 +- 0.1 and 55 +- 0.1 deg C in 0.5 mol L~(-1) KNO_3 solution by means of potentiometric and computer fitting. The DELTAH and DELTAS of the coordination reactions in the solution were given.