The crystal and molecular structures of di-mu-hydroxy-bis(di-2-pyridylamine)dinitratodicopper(II) and aqua-mu-formato-triformato-bis(di-2-pyridylamine)dicopper(II) monohydrate

The preparation, magnetic and spectroscopic properties, crystal and molecul ar structures of binuclear complexes of formulae [Cu-2(dpyam)(2)(OH)(2)(ONO 2)(2)] (I), [Cu-2(dpyam)(2) (O2CH)(4)(OH2)]. H2O (II) are described. (I) co nsists of pairs of copper atoms linked by two hydroxo bridges. The co-ordin ation geometry at each copper atom is distorted square-pyramidal, the basal plane consisting of two hydroxo oxygen atoms and two nitrogen atoms from a dpyam ligand, while the axial co-ordination sites are occupied by nitrate oxygen atoms. The copper(II) ions in (II) are also in a distorted square-py ramidal environment. They are bridged by a formate group in an anti-syn con figuration from a basal position to an axial position, while another axial position is occupied by the water oxygen atom. From magnetic susceptibility measurements at room temperature, both complexes are found to exhibit anti ferromagnetic interactions and some magneto-structural trends are discussed . (C) 1999 Elsevier Science Ltd. All rights reserved.