title: Osmium NAMI-A analogues: synthesis, structural and spectroscopic characterization, and antiproliferative properties.
abstract: The osmium(III) complex [(DMSO)2H][trans-OsIIICl4(DMSO)2] (1) has been prepared via stepwise reduction of OsO4 in concentrated HCl using N2H(4).2HCl and SnCl(2).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), (H2bzim)[OsIIICl4(Hbzim)(DMSO)] (4), (H2im)[OsIIICl4(Him)(DMSO)] (6), and (H2trz)[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.
authors.affiliation: Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Währingerstrasse 42, A-1090 Vienna, Austria.
authors.forename: Berta
authors.initials: B
authors.lastname: Cebrián-Losantos
authors.forename: Artem A
authors.initials: AA
authors.lastname: Krokhin
authors.forename: Iryna N
authors.initials: IN
authors.lastname: Stepanenko
authors.forename: Rene
authors.initials: R
authors.lastname: Eichinger
authors.forename: Michael A
authors.initials: MA
authors.lastname: Jakupec
authors.forename: Vladimir B
authors.initials: VB
authors.lastname: Arion
authors.forename: Bernhard K
authors.initials: BK
authors.lastname: Keppler
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry* / Q000494:pharmacology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004121:Dimethyl Sulfoxide / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D004355:Drug Stability; D006801:Humans; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry* / Q000494:pharmacology; D017892:Osmium Compounds / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D017975:Ruthenium Compounds; D013057:Spectrum Analysis; D013329:Structure-Activity Relationship
chemical_list: D000970:Antineoplastic Agents; D009942:Organometallic Compounds; D017892:Osmium Compounds; D017975:Ruthenium Compounds; C113661:imidazolium-bis(imidazole)dimethylsulfoxideimidazotetrachlororuthenate(III); D004121:Dimethyl Sulfoxide