Trinuclear Copper(II) Bromide Complex [C3H5N3Br]2n[Cu3Br8]n. Structure, Magnetic Properties and DFT calculations.

Halidocuprates(II) show unusual magnetic properties and a high degree of structural flexibility. We present the results of crystallographic, electron paramagnetic resonance (EPR) spectroscopic and magnetochemical analyses of a new [HL]2n[Cu3Br8]n compound (HL = 3–amino–4–bromopyrazolium) – the first example of inorganic polymer built by trimeric [Cu3Br8]2– units with 5-membered nitrogen-containing heterocycle as an organic counter ion. The EPR spectrum of the polycrystalline sample exhibited signal at g ≅ 2.06 broadened owing to spin–spin interactions between copper ions. The EPR and magnetochemical data indicate the ferromagnetic intertrimer interaction with Θ = 13 K and the antiferromagnetic intratrimer interaction with J = 310 K between the nearest-neighbor copper(II) ions which is in agreement with DFT calculations.