Complexes of alkylated 1,4-diazabicyclo[2.2.2]octane with Ag(I) and Gd(III). Synthesis, self-association and biological activity

Abstract

New amphiphilic surfactant-transition metal complexes [Ag(L)(NO3)2], [Ag(2L)(NO3)3] and [Gd(L)Br(NO3)3H2O] (where L is 1-cetyl-4-aza-1-azoniabicyclo[2.2.2]octane) were synthesized and characterized. The composition and 3D structure of the complexes were determined using IR and 1H NMR spectroscopy, elemental analysis, and X-ray diffractometry. Self-assembly and adsorption properties of the amphiphiles in an aqueous medium were studied by tensiometry, conductometry, potentiometry, dynamic and electrophoretic light scattering, transmission electron microscopy and fluorescence of pyrene. The Kraft temperature, the critical micelle concentration, the degree of bromide ion binding with aggregates, the aggregation numbers, the aggregate size, the zeta-potential of the systems, and the adsorption characteristics at the water–air interface were determined. The results obtained were compared with data for single ligand solutions and ligand-inorganic salt mixtures. A high aggregation capacity and morphological rearrangements in metallosurfactant solutions (vesicle-micelle transition) were established. The antimicrobial activity of metallosurfactants (including antibiotic-resistant strains), as well as low hemolytic and cytotoxic effects were shown, which allows them to be classified as potential drugs with a wide spectrum of activity.