From Simple Palladium(II) Monomers to 2D Heterometallic Sodium-Palladium(II) Coordination Networks with 2-Halonicotinates.

The 2D heterometallic sodium-palladium(II) coordination polymers with 2-halonicotinates [2-chloropyridine-3-carboxylate (2-chloronicotinate), 2-Clnic and 2-bromopyridine-3-carboxylate (2-bromonicotinate), 2-Brnic], {[Na(HO)(μ-HO)PdCl(μ-2-Clnic-')]} (), and {[Na(HO)(μ-HO)PdBr(μ-2-Brnic-')]·2HO} () were prepared in aqueous solutions under the presence of NaHCO, while palladium(II) monomers with the neutral 2-chloronicotinic and 2-bromonicotinic acid ligands, [PdCl(2-ClnicH-)]·2DMF () and [PdCl(2-BrnicH-)]·2DMF (), were prepared in DMF/water mixtures (DMF = ,'-dimethylformamide). The zigzag chains of water-bridged sodium ions are in turn bridged by [PdCl(2-Clnic)] moieties in or by [PdBr(2-Brnic)] moieties in , leading to the formation of the infinite 2D coordination networks of or . The DFT calculations showed the halosubstituents type (Cl Br) does not have an influence on the formation of either or isomers. The isomers were found in all reported compounds; being more stable for about 10 to 15 kJ mol. The 2D coordination networks and are more stabilized by the formation of Na-O bonds, comparing to the stabilization of palladium(II) monomers and by hydrogen-bonding with DMF molecules. The difference in DFT calculated energy stabilization for and is ascribed to the type of halosubstituents and to the presence/absence of lattice water molecules in and . The compounds show no antibacterial activity toward reference strains of and bacteria and no antiproliferative activity toward bladder (T24) and lung (A549) cancer cell lines.