Syntheses, Crystal Structures and Antibacterial Properties of Bis(1-benzyl-4′-R-pyridinium)tetrabromocuprate(II) [R = NH2 or N(CH3)2]

Two tetrabromocuprate(II) salts with benzyl substituted pyridinium, [Bz-4-NH2Py](2)[CuBr4] (1) and [Bz-4-N(CH3)(2)Py](2)[CuBr4] (2) ([Bz-4-NH2Py](+) = (1-benzyl-4'-aminopyridinium), [Bz-4-N(CH3)(2)Py](+) = 1-benzyl-4'-dimethylaminopyridinium) were crystallized from methanol and diluted in HBr solution. Compound 1 crystallizes in the orthorhombic Pna2(1), with 2 in the monoclinic P2(1)/n. Two salts are composed of one tetrahedral [CuBr4](2-) anion and two tortuous [Bz-4-NH2Py]+/[Bz-4-N(CH3)(2)Py](+) cations. The [CuBr4](2-) anions in 1 form a linear chain, while the combination of C-H center dot center dot center dot p, C-H center dot center dot center dot Br, C-H center dot center dot center dot N weak hydrogen bonds and pi center dot center dot center dot pi interactions results in the forming of a 3D network structure of 1 and 2. The two salts show good antibacterial activities for E. coli and S. aureus.