MODEL COMPOUNDS FOR THE OXIDIZED UTEROFERRIN PHOSPHATE COMPLEX WITH NOVEL DINUCLEATING LIGANDS CONTAINING PHENOLATE AND PYRIDINE DONORS

Novel dinucleating ligands containing phenol and pyridine were prepared, and their complexing properties toward Fe(III) are studied in order to model the active sites of purple acid phosphatases. Syntheses and crystal structures as well as magnetic, spectroscopic, and electrochemical properties of dinuclear Fe(III) complexes derived from 1,3-bis[(2-hydroxybenzyl)(2-pyridylmethyl)amino]-2-propanol (H3bhpp), 1, and 2,6-bis[((2-hydroxybenzyl)(2-pyridylmethyl)amino)methyl]-4-methylphenol(H3bhpmp), 2, are reported. [Fe2bhpp(O2P(OPh)2)2]BPh4.CHCl3.CH3-OH, 3, and [Fe2bhpmp(O2P(OPh)2)2]ClO4.H2O, 4, were synthesized and characterized by X-ray structure analysis. Both 3 and 4 crystallize in the triclinic space group P1BAR with the following unit cell parameters: 3, a = 14.883(6) angstrom, b = 15.495(7) angstrom, c = 18.149(8) angstrom, alpha = 98.11(4)degrees, beta = 103.59(4)degrees, gamma = 11 1.76(3)degrees, Z = 2; 4, a = 10.526(3) angstrom, b = 16.131(7) angstrom, c = 19.741(9) angstrom, alpha = 84.34(4)degrees, beta = 74.47(3)degrees, gamma = 75.98(3)degrees, Z = 2. Besides the electronic and Mossbauer spectra and cyclovoltammograms the magnetic susceptibilities of 3 and 4 are examined in the temperature range 4.2-290.0 K.