Synthesis, magnetic properties, and crystal structure of dinuclear antiferromagnetic [Cu2(5-aminomethyl-3-methylpyrazole)2Cl4]

The synthesis, optical and magnetic properties and the X-ray crystal structure of [Cu2(amp)2Cl4] (amp=5-aminomethyl-3-methylpyrazole), a new dinuclear chloro-bridged copper(II) compound, are described. Both copper ions are in a distorted square pyramidal N2Cl3 environment, with the apical position of the copper being occupied by the bridging chloride anion, which is equatorial to the other copper. An anti-ferromagnetic coupling of J=−9.4 cm−1 is found, with a rather large zJ′ value of −2.1 cm−1, which is probably due to the different pathways of interaction that exist between the coppers in the crystal lattice. The coppers within each dinuclear unit are connected by the chloride bridges (intra pathway), whereas the coppers from different dinuclear units in the lattice are connected by hydrogen bonds (inter pathway).