Syntheses, crystal structures, weak interactions and magnetic properties of two salts with tetrachlorocuprate(II) and substituted benzylpyridinium

Two tetrachlorocuprate(II) salts, [4-RBzPy]2CuCl4 ([4-RBzPy]+ = 4-R-benzylpyridinium, R = Cl(1), NO2(2)), have been prepared and characterized by elemental analysis, IR, MS, single-crystal X-ray diffraction and magnetic susceptibility. Compound 1 crystallizes in the orthorhombic system with space group Pca21, while 2 in the monoclinic P21/c. Two salts comprise a tetrahedral [CuCl4]2− anion and two flexuous [4-RBzPy]+ cations. The cations both 1 and 2 form a column through p⋯π and π⋯π interactions, while the [CuCl4]2− anions only in 2 form a dimer through Cl⋯Cl interaction. The C–H⋯Cl and C–H⋯Cu weak hydrogen bonds between the anions and the cations give further rise to a 3D network structure. Magnetic susceptibility measurements in the temperature range 2–300 K show that 1 exhibits a ferromagnetic coupling behavior with θ = 3.57 K, while 2 shows an antiferromagnetism with J = −11.09 cm−1.