Thermal behaviour of some biological active perchlorate complexes with a triazolopyrimidine derivative

Abstract

In order to modulate their biological activity in relation with microbial and mammalian cells, new compounds of type M(pmtp)(ClO4)2·nH2O (M: Co, Ni, Cu, Zn; pmtp: 5-phenyl-7-methyl-1,2,4-triazolo[1,5-a]pyrimidine) were synthesised and characterised by chemical analysis, FAB-MS, IR, UV–Vis–NIR, EPR spectroscopy, cyclic voltammetry and magnetic data at room temperature. The thermal behaviour of these derivatives was also investigated by TG–DSC/MS measurements to evidence the changes induced by heating and also the thermodynamics effects that accompany them. Processes as water elimination, perchlorate decomposition, fragmentation and oxidative degradation of the triazolopyrimidine species were observed during the thermal studies. The in vitro screening of the antimicrobial activity was performed against Gram positive (S. aureus, B. subtilis) and Gram negative (E. coli, K. pneumoniae, P. aeruginosa), both reference and clinical multidrug-resistant bacterial strains and Candida albicans fungal strain. The copper(II) complex was the most active against planktonic microbial cells, exhibiting minimum inhibitory concentration values in the range of 31–125 μg mL−1. Remarkably, all complexes showed an inhibitory activity against biofilm development on the inert substratum, showing a promising potential for the design of new efficient anti-biofilm strategies.