Spectroscopic Characterization, In Vitro Cytotoxicity, and Antioxidant Activity of Mixed Ligand Palladium(II) Chloride Complexes Bearing Nucleobases

Mixed-ligand palladium(II) chloride complexes bearing the nucleobases, adenine (Ad), cytosine (Cyt), and guanine (Gua), have been synthesized and characterized by UV-vis spectrophotometric methods, magnetic susceptibility, molar conductivity, elemental analysis, FTIR, and 1H-NMR. The complexes were found to have the composition cis-[PdCl2(Gua)(Cyt)], cis-[PdCl2(Ad)(Cyt)], and cis-[PdCl2(Ad)(Gua)]. A four-coordinated square-planar geometry is proposed for these Pd(II) complexes based on magnetic evidence and electronic spectra. The complexes as well as the free nucleobase ligands were tested for their in vitro cytotoxicity on human promyelocytic leukemia (HL60) and human histiocytic leukemia (U937) cell lines. cis-[PdCl2(Ad)(Gua)] showed IC50 values of 11.29 ± 2.91 and 8.31 ± 1.44 μM against HL60 and U937, respectively, which was higher than that of the positive control (curcumin) against U937. The complexes also showed significant antioxidant activity when tested against 2,2-diphenyl-1-picrylhydrazylradical (DPPH).

Synthesis and structural characterization of Pd(N,N-dimethylaminopropylamine)Cl2 complex--the interaction with bio-relevant ligands with reference to the effect of cysteine on the deactivation of metal-based drug

The synthesis and X-ray structural characterization of Pd(DMPA)Cl(2) complex, where DMPA=N,N-dimethylaminopropylamine, is reported. The complex crystallizes in the space group P2(1)/c, a=8.8923(4), b=10.9050(5), c=11.5006(7) Å, β=120.00(18)°, V=948.25(8) Å(3), Z=4. The palladium centre has a typical square-planar geometry with a tetrahedral distortion. Stoichiometry and stability constants of the complexes formed between [Pd(DMPA)(H(2)O)(2)](2+) and some selected DNA constituents and cytsteine are investigated at 25 °C and at constant 0.1M ionic strength. The concentration distribution diagrams of the various species formed are evaluated. The equilibrium constants for the displacement of coordinated ligands as inosine by cysteine are calculated. The results are expected to contribute to the chemistry of tumour therapy.

Aminopyrazole-based ligand induces gold nanoparticle formation and remains available for heavy metal ions sensing. A simple "mix and detect" approach

A novel way to synthesize gold nanoparticles based on the use of N-alkylaminopyrazole is shown. This ligand has a triple functionality: induces AuNPs formation, stabilizes the formed nanoparticles, and even remains available for an external coordination with heavy metal ions. The availability of N-alkylaminopyrazole ligands onto the AuNPs surface is studied using UV-vis and NMR techniques. The mechanism of formation of AuNPs along with the synthesis optimization and characterization are studied using voltammetry and UV-vis, and the results are discussed in detail. The application of N-alkylaminopyrazole-derived gold nanoparticles in the heavy metal ions sensing is also tested showing a high sensitivity for mercury detection at low concentration level. The functionalization of metal nanoparticles with these receptors followed by heavy metal ions detection represents a simple "mix and detect" approach with interest for several other sensing applications.