Synthesis, Structure, and Magnetic Properties of Di-μ-Pyrazolatodicopper(II) Complexes of 3,5-Bis(Aminomethyl)Pyrazole

Abstract
3,5-Bis(aminomethyl)pyrazole (Hbampz) forms binuclear copper(II) complexes of the formula [Cu2(bampz)2X2] (X = CI, Br). The crystal structure of [Cu2(bampz)2Br2] has been determined by the X-ray method: formula = CuBrN4C5H9, monoclinic, space group P21/n, a = 9.214(1), b = 10.078(1), c = 8.775(1) Å, β = 97.33(1)°, V = 808.1 Å3. Two bampz molecules combine with two copper(II) ions via the pyrazolate nitrogen and aminonitrogen atoms in the side chains affording an essentially planar N4 environment for each metal ion. The Cu-Cu separation is 3.947(5)A. The axial site of each copper is weakly coordinated by a bromide ion with a Cu-Br distance of 2.895(4) A. Cryomagnetic investigations over the temperature range 80-300 K revealed a significant antiferromagnetic interaction through the pyrazolate bridges. The exchange integrals (J) based on the Heisenberg model (H =—2JŜ12) was estimated at—200.8 and—192.0 cm−1 for [Cu2(bampz)2Cl2] and [Cu2(bampz)2Br2], respectively.

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