Preparation, crystal structure, spectroscopic and magnetic characterisation of acetatobis(di-2-pyridylamine)copper(II) tetrafluoroborate and μ-carbonato-tetrakis(di-2-pyridylamine) dicopper(II) bistetrafluoroborate tetrahydrate

The crystal structures of [Cu(dpyam)2(O2CCH3)][BF4] (1) and [Cu2(dpyam)4(CO3)][BF4]2·4H2O (2) have been determined by X-ray analysis. 1 involves the distortion of the CuN4O2 chromophore towards a square pyramidal (4+1+1*) stereochemistry which is best described as involving a square-pyramidal distorted octahedral stereochemistry of the six-coordinate CuN4OO′ chromophore. Compound 2 has a dinuclear cation with five-coordinate copper(II) ions bridged asymmetrically by a bidentate carbonate ligand. Both copper(II) ions predominantly involve the distorted square-pyramidal (4+1) stereochemistry of the CuN3ON′ chromophore. The polycrystalline ESR spectra of 1 and 2 are exchange coupled and temperature independent. In 2 the room temperature effective magnetic moment of 1.34 μB indicates the partial spin pairing by antiferromegnetic coupling.