Magnetic resonance spectra of some homo- and hetero-dinuclear paramagnetic metal complexes with 1,5-diphenyl-pentane-1,3,5-trione

Abstract

The spectroscopic and magnetic properties of heterodinuclear transition metal complexes are a topic of current chemical interest, since they can largely expand the number of experimental data on exchange interactions and give new information to correlate the magnetic properties with the structural features of the complexes. Magnetic resonance spectroscopy has been shown to provide powerful tools for detecting and investigating such chemical species [1, 2]. In particular PMR can provide information on the role of the ligands on the superexchange pathway as well as on the electronic states of the coupled metal pairs, while ESR can be used to obtain the spin hamiltonian parameters, which help in the interpretation of the PMR experimental data. We have considered the complexes formed by the tridentate ligand 1,5-diphenyl-pentane-1,3,5-trione. This ligand is known [3] to form dinuclear antiferromagnetically coupled nickel(II) and cobalt(II) complexes of general formula M 2L 2(py) 4·4py (py = pyridine). We have also synthesized the manganese(II) and zinc(II) derivatives and solid compounds containing the heterodinuclear complexes. Their ESR and 1H NMR spectra will be reported and discussed.