engleski

Palladium(II) complexes with N-alkyliminodiacetic acid derivatives: preparation, structural and spectroscopic studies

The reactions of N-alkyl derivatives of iminodiacetic acid, RN(CH2COOH)2 (i-PridaH2 and t-BuidaH2 ; i-Pr = isopropyl, t-Bu = tert-butyl) with sodium tetrachloropalladate(II) in aqueous solutions were investigated. Four new palladium(II) complexes {; ; ; ; ; ; ; [Na[PdCl(i-Prida)](H2O)2] ∙ ½H2O}; ; ; ; ; ; ; n (1), [Na[PdCl(t-Buida)](H2O)2]n (2), [Pd(i-PridaH)2] ∙ 2H2O (3) and [Pd(t-BuidaH)2] (4) were obtained and characterized by X-ray crystallography, infrared spectroscopy, 1H and 13C NMR spectroscopy, UV-Vis spectroscopy and thermal analysis (TG/DTA). In the solid state, the palladium(II) ion has square-planar coordination in all four complexes, composed of an O, N, O’-tridentate iminodiacetate ligand and a chloride ion in 1 and 2 and of two N, O-bidentate hidrogeniminodiacetate ligands in 3 and 4. Moreover, 1 is 2D coordination polymer composed of sodium ion clusters bridged by [PdCl(i-Prida)]‒ moieties, 2 is 1D coordination polymer composed of a zig-zag chain of sodium ions bridged by [PdCl(t-Buida)]‒ moieties and water molecules, while complexes 3 and 4 are monomeric species. Substitution of the chloride ligands in [PdCl(i-Prida)]‒ and [PdCl(t-Buida)]‒ by water molecules takes place after dissolution of the complexes 1 and 2, leading to formation of [Pd(i-Prida)(H2O)] (1') and [Pd(t-Buida)(H2O)] (2') species. Spectrophotometric potentiometric titration revealed that [PdCl(i-Prida)]‒ and [PdCl(t-Buida)]‒ are stable in acidic aqueous solution in the pH range 3-6 in the presence of chloride ions at [Cl–] > 0.1 M. Complexes 3 and 4 partially decompose upon dissolution in dimethyl sulfoxide, giving mixtures of the original complexes and by-products whose NMR spectra resemble those of 1' and 2'. Antibacterial and antitumor properties of the water-soluble complexes 1' and 2' were also investigated.

Palladium(II) ; Iminodiacetate ; Coordination polymer ; Spectrophotometric potentiometric titration

Rad je financirala Zaklada Hrvatske akademije znanosti umjetnosti za akad. god. 2015./2016.