Effect of structural features on the stability and bactericidal potential of two cadmium coordination polymers

Abstract

The emergence of new infectious diseases and their high mortality rate reveals the need for more attention to this area and the synthesis of new compounds. In this work, two mixed ligand cadmium(II) coordination polymers of [Cd(Phac)₂(Dabco)(H₂O)]_n (1) and [Cd(Phac)(4,4′-Bpy)(OAc)]_n (2) (Phac = phenylacetate, Dabco = 1,4-diazabicyclo[2.2.2]octane, 4,4′-Bpy = 4,4′-bipyridine, OAc = acetate) have been synthesized by the solvothermal, sonochemical and mechanochemical methods. Single-crystal X-ray diffraction analysis, Fourier-transform infrared (FT-IR) spectroscopy, X-ray powder diffraction (XRPD), field emission scanning electron microscopy (FE-SEM) and thermal techniques (TG-DTG) were used to study these compounds. In both compounds, phenylacetate is obtained by in situ decarboxylation of phenylmalonic acid. The stability and in vitro antibacterial activity of the compounds were investigated. Metal–ligand bond strength, pillar size, ligand shielding effect, and the nature of network expansion bonds were influential factors in the stability. More stability and the consequent higher lipophilicity of particles were associated with improved antibacterial activity for 1. Nano-grains in the bulk structure of compounds were also identified as a determining factor in antibacterial activity.