Thermoanalytical investigation and biological properties of zinc(II) 4-chloro- and 5-chlorosalicylates with N-donor ligands

Abstract

Abstract New zinc(II) 4- and 5-chlorosalicylate complexes of general formula [Zn(X-sal)2(L)n(H2O)x] (where X-sal = 4-Clsalicylate, 5-Clsalicylate; L = N,N-diethylnicotinamide, isonicotinamide, theophylline; n = 1, 2; x = 0, 1, 2, 4) were prepared. The complexes were determined by elemental analysis and characterised by infrared spectroscopy. The thermal behaviour of the complexes was studied by simultaneous TG, DTG and DTA methods under dynamic air conditions. The thermal decomposition is a multi-step process. In the first step of the thermal decomposition, water is released in hydrated compounds. The anhydrous compounds start to decompose by the release of organic ligand, followed by chlorosalicylic acid, chlorophenol and carbon monoxide. The final solid product of the thermal decomposition is zinc oxide. The volatile products of the thermal decomposition were determined by mass spectrometry. The antimicrobial activities of the complexes were evaluated against selected pathogen and probiotic bacteria, ye...