Synthesis, crystal structure and magnetic properties of the malonato-bridged bimetallic chain [Mn(II)Cu(II)(mal)(2)(H2O)(4)]center dot 2H(2)O

The first malonato-bridged bimetallic chain of formula [MnCu(mal)(2)(H2O)(4 )]. 2H(2)O (1) (H(2)mal = malonic acid) was prepared and its structure dete rmined by X-ray diffraction methods. Each copper atom in 1 is in a square p lanar environment formed by four malonate-oxygens from two malonate ligands . The manganese atom is six-coordinated with four water molecules and two c is-coordinated malonate-oxygens from two malonate groups building a distort ed octahedral surrounding. The malonate group acts simultaneously as bident ate and monodentate ligand towards copper and manganese atoms respectively, leading to a bimetallic chain. Two structurally different carboxylato-brid ges exhibiting an anti-syn conformation alternate regularly within the chai n, the intrachain copper-manganese separations being 4.790(1) and 5.209(1) Angstrom. Its magnetic behaviour is typical of a ferrimagnetic Cu(II)Mn(II) bimetallic chain with intrachain antiferromagnetic coupling. The fully deh ydrated phase of complex 1 exhibits an overall antiferromagnetic behaviour. (C) 2000 Elsevier Science S.A. All rights reserved.