Synthesis, characterization and antimicrobial activity of N,N-bis(hydroxymethyl)-N-[(2-mercaptoacetoxy)methyl]alkyl ammonium bromide surfactant and their Co(II), Zn(II) and Sn(II) complexes

Two-membered cationic surfactants namely: N,N-bis(hydroxymethyl)-N-[(2-mercaptoacetoxy)methyl)dodecane ammonium bromide (C12Q) and N,N-bis(hydroxymethyl)-N-[(2-mercaptoacetoxy)methyl]hexadecane ammonium bromide (C16Q) and their cobalt, tin and zinc complexes (C12QCo, C12QSn, C12QZn, C16QCo, C16QSn and C16QZn) were synthesized. The chemical structures of the synthesized compounds were confirmed using different spectroscopy tools. The surface activities of the synthesized surfactants were influenced by their chemical structures and the type of the transition metals. The synthesized cationic surfactants and their metal complexes were evaluated as biocides against Gram- positive bacteria (Bacillus subtilis and Micrococcus luteus), Gram-negative bacteria (Bordetella pertussis and Escherichia coli) and fungi (Candida albicans and Aspergillus niger), while the sulfate-reducing bacteria were tested against Desulfomonas pigra. The biological activity results showed that the cationic surfactants exhibit moderate to high efficiency against the tested microorganisms. The antimicrobial activity was strongly increased by complexation of these cationic surfactants with Co(II), Sn(II) and Zn(II) ions. The antimicrobial activity of the synthesized compounds against sulfate-reducing bacteria showed promising results in the field of biocides application.