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

Two tetrachlorocuprate(II) salts, [4-RBzPy](2)[CuCl4] ([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 Pca2(1), while 2 in the monoclinic P2(1)/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 center dot center dot center dot pi and pi center dot center dot center dot pi interactions, while the [CuCl4](2) anions only in 2 form a dimer through Cl center dot center dot center dot Cl interaction. The C-H center dot center dot center dot Cl and C-H center dot center dot center dot 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 theta = 3.57 K, while 2 shows an antiferromagnetism with J = -11.09 cm (1). (C) 2011 Elsevier B.V. All rights reserved.