Abstract (EN):
The copper(II) complex [Cu(p-Tdp)(H2O)(2)].2H(2)O, where p-Tdp is the anion of p-toluidine-N,N-di-3-propionic acid (or N,N-di(2-carboxyethyl)-p-toluidine), has been synthesized and characterized by X-ray diffraction. Three crystallographically independent [Cu(p-Tdp)(H2O)(2)] molecules have a similar structure. The Cu atoms have a square pyramidal environment (4+1) with a small trigonal bipyramidal distortion. The ortho-H atom of the benzene ring blocks up the sixth coordination position of the Cu polyhedron. The basal plane is formed by the donor atoms of the tridentate ligand and by the water molecule (average bond length Cu-N 2.03, Cu-O 1.93, Cu-O-w 2.00 Angstrom), the apex is occupied by another water molecule (Cu-O-w 2.27 Angstrom). The Cu atoms are located 0.20-0.30 Angstrom out of the mean planes of the four basal atoms towards the apical O-w atom. The IR and electronic absorption spectra of p-Tdp and the title compound have been described. UV-Vis reflectance spectra shows that the complex has the same square pyramidal geometry in the crystal state and in solution. The protonation constants of the ligand log K-1 = 6.87(2), log K-2 = 3.75(2), log K-3 = 2.57(2) and stability constants log KCuH(p-Tdp) = 2.13(5), log KCu(p-Tdp) = 6.38(3) were determined by pH-titration at 25.0 degreesC and I = 0.1 M KNO3.
Idioma:
Inglês
Tipo (Avaliação Docente):
Científica
Nº de páginas:
7