Synthesis, crystal structure and magnetic properties of bis(1,1,1,5,5,5-hexafluoropentane-2,4-dionato)manganese(II) complexes with diazine ligands

One dinuclear [Mn-2(hfac)(4)(mu-pyz)(H2O)(2)]2H(2)O (1) and three mononuclear complexes [Mn(hfac)(2) (pym)(H2O)] (2), [Mn(hfac)(2)(pydz)(2)] (3), and [Mn(hfac)(2)(mpydz)(2)] (4) (Hhfac = 1,1,1,5,5,5-hexafluoropentane-2,4-dione, pyz = pyrazine, pym = pyrimidine, pydz = pyridazine, and mpydz = 3-methylpyridazine) have been synthesized and their crystal structures and cryomagnetic properties have been investigated. Complex 1 has a centrosymmetric dinuclear structure with two adjacent manganese atoms linked by a pyz ligand. The geometry about each manganese atom is distorted octahedral with NO5 coordination sphere. The structure of complex 2 is a mononuclear manganese complex With a distorted octahedral geometry of NO5 coordination sphere. The crystal structures of complexes 3 and 4 consist of mononuclear manganese complex with the cis-N2O4 six-coordination sphere. The temperature dependence of magnetic data for 1 revealed a dinuclear spin (S-1 = S-2= 5/2) weak antiferromagnetic exchange interaction with J = -0.47 cm(-1). Complexes 2-4 play a cryomagnetic behaviour followed the Curie-Weiss law. (C) 1998 Elsevier Science Ltd. All rights reserved.