The effect of partial substitution of chloride by bromide in the 0-D hybrid material (C4H12N2)[CuCl4]•2H2O: Structural, vibrational, thermal, in silico and biological characterizations

A new organic-inorganic hybrid material with copper(II) as the transition metal, piperazine as the organic component and mixed bromide/chloride as halide ions, (C4H12N2)[CuBr4](0.42)[CuCl4](0.58)center dot 2H(2)O (1), has been prepared and crystallographically investigated by single-crystal X-ray diffraction. Unlike the parent chloride or bromide-based materials which adopt the monoclinic system, this mixed halide hybrid material crystallizes in the space group Pnma of the orthorhombic system with the following parameters: a = 12.3496(6) angstrom, b = 16.3147(11) angstrom, c = 6.4415(3) angstrom, V = 1397.83(12) angstrom(3) and Z = 4. Its 0-D crystal packing is built of isolated entities, a copper(II) ion surrounded by four chloride/bromide ions [CuBr4](2-) and [CuCl4](2-), a diprotonated diamine (C4H12N2)(2+) and free water molecules. Additionally, these entities are linked through different types of intermolecular hydrogen bonds N-H horizontal ellipsis Br, N-H horizontal ellipsis Cl, N-H horizontal ellipsis Ow, Ow-H horizontal ellipsis Br, Ow-H horizontal ellipsis Cl, and weak non-covalent interactions C-H horizontal ellipsis Br and C-H horizontal ellipsis Cl [Ow = water oxygen]. The thermal decomposition of the precursor proceeds through four stages leading to copper(II) oxide as a final product. The title compound possesses antimicrobial and anti-tumoral effects comparable to two previously described compounds, as assessed by in silico examinations. Compound 1 inhibited in a dose dependent manner, the proliferation of gram negative and positive bacteria and exhibited a microbial lipase inhibition from Candida rugosa.