New non-toxic transition metal nanocomplexes and Zn complex-silica xerogel nanohybrid: Synthesis, spectral studies, antibacterial, and antitumor activities

•A new Schiff base and its complexes as well as Zn(II) complex-silica xerogel nanohybrid were prepared.•The complexes were characterized by analytical and spectral methods.•TEM analysis showed that Ni(II) and Zn(II) complexes have aggregated spheres and rod morphologies, respectively.•The obtained nanocomplexes were tested as antimicrobial and antitumor agents.•Some complexes showed lower toxicity than cisplatin.

A new chromone Schiff base and its complexes of Cu(II), Ni(II), Co(II), Fe(III), Zn(II), Cd(II), and UO2(VI) as well as Zn(II) complex-silica xerogel nanohybrid were successfully prepared in a nano domain with crystalline or amorphous structures. Structures of the Schiff base and its complexes were investigated by elemental and thermal analyses, IR, 1H NMR, electronic, ESR, mass spectra, XRD, and TEM, as well as conductivity and magnetic susceptibility measurements. The spectroscopic data revealed that the Schiff base ligand behaves as a monobasic tridentate ligand. The coordination sites with metal ions are γ-pyrone oxygen, azomethine nitrogen, and oxygen of the carboxylic group. The metal complexes exhibited octahedral geometry, except Cu(II) complex, which has a square planar geometry and UO2(VI) complex, in which uranium ion is hepta-coordinated. Transmission electron microscope (TEM) analysis showed that Ni(II) and Zn(II) complexes have aggregated spheres and rod morphologies, respectively. TEM images of Zn(II) complex-silica xerogel nanohybrid showed a nanosheet morphology with 46 nm average size and confirmed that the complex was uniformly distributed into the silica pores. The obtained nanocomplexes were tested as antimicrobial and antitumor agents. The results showed that Zn(II) nanocomplex and Zn(II) complex-silica xerogel nanohybrid have high activity. The toxicity test on mice showed that Zn(II) complex and Zn(II) complex-silica xerogel nanohybrid have lower toxicity than cisplatin.

Graphical abstractTEM image of complex 5, [(L)2Zn]·3.5H2OFigure optionsDownload full-size imageDownload as PowerPoint slide