Preparation and characterization of palladium(II) complexes with N-arylalkyliminodiacetic acids. Catalytic activity of complexes in methoxycarbonylation of iodobenzene

• The reactions of N-arylalkyliminodiacetic acids with Pd(II) were investigated.
• The complexes were characterized by spectroscopic and thermal measurements.
• Square-planar coordination of Pd(II) was established in trans isomer.
• The complexes did not significantly inhibit the growth of human tumor cell lines.
• The complexes exhibit catalytic activities (methoxycarbonylation of iodobenzene).

The reactions of N-arylalkyl derivatives of iminodiacetic acid (H2Bnida, H2Peida, H2Ppida, o-H2Cbida; Bn = benzyl, Pe = 2-phenylethyl; Pp = 3-phenylprop-1-yl; o-Cb = o-chlorobenzyl) with sodium tetrachloropalladate(II) in aqueous solutions were investigated. Five new palladium(II) complexes [Pd(HBnida)2]·2H2O (1a), [Pd(HBnida)2] (1b), [Pd(HPeida)2] (2), [Pd(HPpida)2] (3) and [Pd(o-HCbida)2] (4) were prepared and characterized by infrared spectroscopy, 1H, 13C and 15N NMR spectroscopy and thermal analysis (TGA/DTA). The crystal structure of 1a was determined by single-crystal X-ray structural analysis. The palladium(II) ion in the molecule of 1a adopts a square planar coordination with two N,O-bidentate N-benzyl-hydrogeniminodiacetate ions. Complex 1a is a trans-isomer. Antitumor properties of the complexes were tested on three human cell lines. The compounds did not significantly inhibit the growth of colon (HCT 116), breast (MCF-7) and lung (H 460) tumor cell lines. All prepared palladium(II) complexes exhibit the acceptable activities towards the methoxycarbonylation of iodobenzene.

The complexes were prepared from sodium tetrachloropalladate(II), sodium hydroxide and the appropriate N-arylalkyliminodiacetic acid in slightly acidic aqueous solution. Palladium(II) ion is placed at the inversion center and coordinated by two N,O-bidentate HBnida− ligands in 1a, resulting with the square-planar coordination and the formation of trans isomer.Figure optionsDownload as PowerPoint slide