Five new pseudohalide bridged Mn(II) complexes of pyrimidine derived Schiff base ligands: Synthesis, crystal structures and magnetic properties

Four new azide bridged dinuclear Mn(II) complexes [mn(L-1)(mu(1,1)-N-3)(N-3)](2) (1), [mn(L-2)(mu(1.1)-N-3)(N-3)](2) (3), [Mn(L-3)(mu(1,1)-N-3)(N-3)](2)[(N-3)Mn(L-3)(mu(1,1)-N-3)(N-3)](2) (4) and [Mn(L-4)(mu(1.1)-N-3)(N-3)](2)[Mn(L-4)(mu(1,1)-N-3)(N-3)](2) (5) and one new dicynamide bridged binuclear Mn(II) complex {[Mn-2(L-1)(2)(dca)(2)(H2O)(2)(mu(1.5)-dca)](CLO4)} (2) have been synthesized using the pyrimidine derived primary Schiff base ligands L-n (n = 1-4), with azide and dicynamide as bridging ligands. All the five complexes were characterized by elemental analyses, IR spectroscopy and single crystal X-ray crystallography, together with magnetic measurements of 1-4. The tridentate Schiff base ligands are the [1 +1] condensation products of 2-hydrazino-4,6-dimethyl pyrimidine with 2-acetyl pyridine, pyridine-2-carbaldehyde, 2-benzoyl pyridine and di(2-pyridyl) ketone for L-n (n = 1-4), respectively. All the complexes except 2 contain Mn(II)-azido links in which the Mn(II) centres are bridged by a di-mu(1,1)-azido (double EC)) group. The double EO bridging fragments in the complexes are similar with bridging angles (Mn-N-Mn) ranging from 102.59 degrees to 104.81 degrees. Magnetic property studies reveal that in 1, 3 and 4 intramolecular ferromagnetic interactions are mediated through the EO azido bridges with J parameters in the range 4.3-5.12 cm(-1), while a weak antiferromagnetic interaction prevails in 2 (1= -0.12 cm(-1)) via mu(1,5)-dicynamide bridges. In addition, complexes 1, 3 and 4 show weak intermolecular antiferromagnetic interactions (J = -0.025 to -0.027 cm(-1)). (C) 2013 Elsevier Ltd. All rights reserved.