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Synthesis, structure, electronic and magnetic properties of two new complexes obtained by coordination of Co(II) and Mn(II) phenyltrifluoroacetylacetonate with a nitronyl nitroxide radical

2008; Elsevier BV; Volume: 361; Issue: 14-15 Linguagem: Inglês

10.1016/j.ica.2008.03.043

1873-3255

Denise A. Souza, Antonio S. Florencio, José Walkimar de M. Carneiro, Stéphane Soriano, Carlos B. Pinheiro, Miguel A. Novak, Maria G. F. Vaz,

Metal complexes synthesis and properties

Abstract Two new magnetic compounds were obtained by using β-diketonate 1,3-butanedione, 4,4,4-trifluoro-1-phenyl (Phtfac) as ligand. The complexes with formula [M(Phtfac)2(NITpPy)2 [M = Co(II) 1, Mn(II) 2; NITpPy = 4-pyridyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide] were characterized structurally and magnetically. Both structures consist of [M(II)(Phtfac)2(NITpPy)2] units, where the metal ion is in an octahedral environment bound to two NITpPy through the nitrogen atom of the pyridine ring. Compound 1 is the first case where a nitronyl nitroxide radical is coordinated to cobalt linked by the β-diketonate by the nitrogen atom of the pyridine ring. The magnetic behavior of this compound indicates that the cobalt ion and the NITpPy ligand are antiferromagnetically coupled with a coupling constant of −4.3 cm−1. The manganese derivative shows a ferromagnetic behavior with a coupling constant of 3.0 cm−1. The discussion of the electronic structure based on DFT calculations allows the rationalization of the ferromagnetic behavior.