Osmium NAMI-a analogues: Synthesis, structural and spectroscopic characterization, and antiproliferative properties

Author(s)
Bernhard Keppler, Berta Cebrian, Artem Krokhin, Iryna Stepanenko, Rene Eichinger, Michael Jakupec
Abstract

The osmium(III) complex [(DMSO)2H][trans-OsIIICl 4(DMSO)2] (1) has been prepared via stepwise reduction of OsO4 in concentrated HCl using N2H4·2HCl and SnCl2·2H2O in DMSO. 1 reacts with a number of azole ligands, namely, indazole (Hind), pyrazole (Hpz), benzimidazole (Hbzim), imidazole (Him), and 1H-1,2,4-triazole (Htrz), in organic solvents, affording novel complexes (H2ind)[OsIIICl4(Hind)(DMSO)] (2), (H2pz)[OsIIICl4(Hpz)(DMSO)] (3), (H 2bzim)-[OsIIICl4(Hbzim)(DMSO)] (4), (H 2im)[OsIIICl4(Him)(DMSO)] (6), and (H 2trz)[OsIIICl4(Htrz)(DMSO)] (7), which are close analogues of the antimetastatic complex NAMI-A. Metathesis reaction of 4 with benzyltriphenylphosphonium chloride in methanol led to the formation of (Ph3PCH2Ph)[OsIIICl4(Hbzim)(DMSO)] (5). The complexes were characterized by IR, UV-vis, ESI mass spectrometry, 1H NMR spectroscopy, cyclic voltammetry, and X-ray crystallography. In contrast to NAMI-A, 2-4, 6, and 7 are kinetically stable in aqueous solution and resistant to hydrolysis. Surprisingly, they show reasonable antiproliferative activity in vitro in two human cell lines, HT-29 (colon carcinoma) and SK-BR-3 (mammary carcinoma), when compared with analogous ruthenium compounds. Structure-activity relationships and the potential of the prepared complexes for further development are discussed. © 2007 American Chemical Society.

Organisation(s)
Department of Inorganic Chemistry
Journal
Inorganic Chemistry
Volume
46
Pages
5023-5033
No. of pages
11
ISSN
0020-1669
Publication date
2007
Peer reviewed
Yes
Austrian Fields of Science 2012
104003 Inorganic chemistry
Portal url
https://ucrisportal.univie.ac.at/en/publications/2073d968-f3c0-4169-a95b-7c3bff2af958