Trinuclear copper() bromide complex [CHNBr][CuBr]. 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] 2 n [Cu 3 Br 8 ] n compound (HL = 3-amino-4-bromopyrazolium) - the first example of an inorganic polymer built from trimeric [Cu 3 Br 8 ] 2− units with a 5-membered nitrogen-containing heterocycle as an organic counter ion. The EPR spectrum of the polycrystalline sample exhibited a signal at g ≅ 2.06 broadened owing to spin-spin interactions between copper ions. The EPR and magnetochemical data indicate a ferromagnetic intertrimer interaction with Θ = 13 K and an antiferromagnetic intratrimer interaction with J = 310 K between the nearest-neighbor copper( ii ) ions, which is in agreement with DFT calculations. Halidocuprates( ii ) show unusual magnetic properties and a high degree of structural flexibility.