Gabriel Buechel - [OsIVCl5(Hazole)]- Complexes: Synthesis, Structure, Spectroscopic Properties, and Antiproliferative Activity

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      Publication Details (including relevant citation   information):

      Inorganic Chemistry  2009, 48, 10737-10747.



    By exploring the Anderson type rearrangement reactions, osmium(IV) complexes of the general formula [cation]+[OsIVCl5(Hazole)], where [cation]+ = n-Bu4N+, Hazole = 1H-pyrazole (Hpz) (1), 1H-indazole (Hind) (2), 1H-imidazole (Him) (3), 1H-benzimidazole (Hbzim) (4), 1H,2,4-triazole (Htrz) (5), have been synthesized. To improve water solubility of tetrabutylammonium compounds, complexes with [cation]+ = Na+[Hazole = Hpz (6), Hind (7), Htrz (8)] or H2azole+ [Hazole = Hpz (9), Hind (10), Htrz (11)] have been also prepared with the aim of testing them for cytotoxicity in cancer cells. In addition, the preparation of the complex {(n-Bu4N)2[OsIVCl6]}2[OsIVCl4(Him)2] (12) is also reported. The compounds have been comprehensively characterized by elemental analysis, ESI mass spectrometry, spectroscopy (IR, UV–vis, 1D and 2D NMR), cyclic voltammetry, X-ray crystallography (15, 6 and 12) and magnetic susceptibility (5). Complexes   6–8 are   kinetically inert in aqueous solution and resistant to   hydrolysis. They were found to possess modest antiproliferative   acitivity in vitro  against CH1 (ovarian carcinoma), A549 (non–small cell lung   carcinoma) and SW480 (colon adenocarcinoma) cells with   IC50 values in 10–4 M concentration range.   Replacement of azolium cations by sodium had significant effects,   cytotoxicity increased in case of the pyrazole system from 3   (A549) to the 5.5 –fold (CH1).

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