Département de chimie moléculaire

The electronic structure of 11 pentacoordinated dichloride mononuclear Mn(II) complexes [Mn(L)Cl2] (L = Cl-terpy, Br-terpy, OH-terpy, phenyl-terpy, tolyl-terpy, mesityl-terpy, EtO-terpy, Me2N-terpy, tBu3-terpy, py-phen, and dpya) was studied by a multifrequency EPR study (9-285 GHz). The x-ray structures of [Mn(Br-terpy)Cl2], [Mn(EtO-terpy)Cl2], [Mn(Me2N-terpy)Cl2] and [Mn(tolyl-terpy)Cl2] are described. The spin Hamiltonian parameters were detd. for all complexes and show that the steric and electronic effects of the N-tridentate ligand L do not induce appreciable variations on the zero field splitting parameters. The magnitude of D, close to 0.3 cm-1, is governed by the chloride anion. High-field EPR spectroscopy allows the detn. of electronic parameters of mononuclear Mn(II) complexes characterized by relatively large magnitudes of D and the unambiguous interpretation of the X-band spectra of these kinds of complexes. [on SciFinder(R)]