COMPLEXES WITH DIIMINE LIGANDS .3. SYNTHESIS, STRUCTURE AND MAGNETIC STUDIES OF MIXED ACETYLACETONATECOBALT(II) DERIVATIVES

The synthesis and properties of the mononuclear [Co(L)(hfacac)2], [Co(L)(tfacac)2] and of the dinuclear complexes [Co2(L)(acac)4], where L is 2,3-bis(2-pyridyl)pyrazine (DPP), 2,3-bis(2-pyridyl)quinoxaline (DPQ), 6-methyl-2,3-bis(2-pyridyl)quinoxaline (MeDPQ), 6,7-dimethyl-2,3-bis(2-pyridyl)quinoxaline (DMeDPQ), 6-chloro-2,3-bis(2-pyridyl)quinoxaline (ClDPQ), 2,3-bis(2-pyridyl)benzoquinoxaline (BDPQ); hfacac, tfacac and acac being hexafluoroacetylacetonate, trifluoroacetylacetonate and acetylacetonate, respectively, are described. The structures of [Co(L)(hfacac)2] where L = BDPQ and DMeDPQ were solved. The [Co(BDPQ)(hfacac)2] complex crystallizes in the P1BAR space group with cell parameters a = 14.382(4), b = 12.853(3), c = 9.094(3) angstrom, alpha = 92.55(3), beta = 100.80(3), gamma = 94.54(3)-degrees and Z = 2. The [Co(DMeDPQ)(hfacac)2] complex crystallizes in the P2(1)/a space group with cell parameters a = 19.130(5), b = 9.248(3), c = 18.198(4) angstrom, beta = 95.18(3)-degrees and Z = 4. Magnetic properties of the dinuclear complexes and a study of the coordination possibilities of this kind of ligands are presented.