Novel hybrid materials based on heteroleptic Ru(III) complexes immobilized on SBA-15 mesoporous silica as highly potent antimicrobial and cytotoxic agents

Three novel hybrid materials, SBA-15-RuValen, SBA-15-RuValpnol, and SBA-15-RuValdiamci, were obtained by immobilization of new [Ru(L)(PPh3)Cl] complexes (H2L = H(2)Valen, H(2)Valpnol, H(2)Valdiamci, are Schiff base proligands obtained by condensation of o-vanillin with ethylenediamine, 1,3-diamino-2-propanol, and 1,2-diaminocyclohexane, respectively) inside the mesoporous channels of SBA-15. [Ru(Valen)(PPh3)Cl]center dot 3H(2)O (RuValen), [Ru(Valpnol)(PPh3)Cl]center dot 3H(2)O (RuValpnol), and [Ru(Valdiamci)(PPh3)Cl]center dot 4H(2)O (RuValdiamci) complexes were characterized by microanalysis (C,H,N), IR and UV-Vis spectroscopy, magnetic measurements. The structure of RuValen was also confirmed by single crystal X-ray diffraction. The hybrid materials were thoroughly characterized in terms of structure, composition, morphology, and textural properties. The results indicate the uniform distribution of Ru(III) complexes on the internal surface of SBA-15, the immobilization process having no significant influence on the structure of the support. The novel hybrid materials demonstrated high antibacterial and anti-biofilm activity against Enterococcus faecalis, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. In vitro tests regarding the cytotoxic effect on adenocarcinoma (HeLa) cells showed that all three hybrid materials decreased the cell viability in a dose-dependent manner, being very promising for medical applications.