Crystal structure of polymeric bis(3-amino-1H-pyrazole)cadmium dibromide

Abstract

The reaction of cadmium bromide tetrahydrate with 3-aminopyrazole (3-apz) in ethanolic solution leads to tautomerization of the ligand and the formation of crystals of the title compound, catena-poly[[dibromidocadmium(II)]-bis(μ-3-amino-1H-pyrazole)-κ2N3:N2;κ2N2:N3], [CdBr2(C3H5N3)2]n or [CdBr2(3-apz)2]n. Its asymmetric unit consists of a half of a Cd2+ cation, a bromide anion and a 3-apz molecule. The Cd2+ cations are coordinated by two bromide anions and two 3-apz ligands, generating trans-CdN4Br2 octahedra, which are linked into chains by pairs of the bridging ligands. In the crystal, the ligand molecules and bromide anions of neighboring chains are linked through interchain hydrogen bonds into a two-dimensional network. The intermolecular contacts were quantified using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing the relative quantitative contributions of the weak intermolecular contacts.

Keywords

• crystal structure
• cadmium complex
• coordination polymer
• hydrogen bonding