Crystal structure of μ-terephthalatobis[bis(1,3-diaminopropane)- manganese(II)] diperchlorate, [Mn2{C3H6(NH2)2}4{C6H4(COO)2}][ClO4]2

Abstract

Source of materialMn(ClO 4 ) 2 · 6H 2 O, equimolar terephthalic acid and two equivalent molar 1,3-diaminopropane were dissolved in 30 % aqueous ammonium solution, with stirring, giving a clear pale pink solution, which was stood in air for three days, and pink prism crystals were precipitated. These were filtered and washed with water for three times and dried in vacuo using CaCl 2 (yield 58 %). DiscussionTransition metal terephthalate complexes with various organic amine ligands are a hot topics in the field coordination chemistry. Recently, some of these kinds of complexes were prepared and structurally determinated by single X-ray structure analysis [1][2][3][4]. Due to their biologically relevant important behaviors, many manganese complexes with polyamine ligands have been reported [5][6][7], however, to our knowledge, there are no structure reports about manganese(II,III) terephthalate complexes with organic amine molecules. The title crystal structure consists of one dinuclear manganese(II) complex cation and two perchlorate anions. In the cation, there are two equivalent manganese(II) atoms, bridged by a m 2 -terephthalate dianion at the distance of 11.810 Å. Each manganese atom is coordinated by four nitrogen atoms from two 1,3-diaminopropane molecules and one oxygen atom from a benzoate group of the terephthalate, the latter behaved as a m 2 bridge. The metal atom is in a square-pyramidal environment, with the four N atoms being the basal plane of the polyhedron. The mean deviation of the basal plane is 0.055 Å, and the metal atom is 0.140 Å above the plane towards the apical oxygen atom. This plane is nearly perpendicular to the intra-molecular benzene ring with a dihedral angle of 89.2°. In order to minimize the steric strain of the neighboring atoms, the carboxylate group is deviated from the aromatic ring to which it is attached at the angle of 6.5°. As expected, the six-membered cycle consists of one manganese atom and one 1,3-diaminopropane molecule in a typical chain conformation, with the Mn atom and a C atom occupying the apical positions of the chair. All the nitrogen atoms, three of the four oxygen atoms of each perchlorate anion and the uncoordinated oxygen atoms in the carboxylate groups participate to form intra-and intermolecular hydrogen bonds, which first join the molecules into one-dimensional chains along the b axis and then into two-dimensional layers parallel to the a,b plane.