Synthesis, structure and cytotoxicity of diorganotin(IV) complexes of 2,6-lutidine-α,3-diol (Lu): The crystal structures of Lu and [SnMe2(H2O)(Lu-2H)]

The reaction of dimethyl-, diethyl- and dibutyltin(IV) oxide with 2,6-lutidine-α²,3-diol (Lu) [2-(hydroxymethyl)-3-hydroxy-6-methylpyridine] in toluene/ethanol has been investigated. The compounds were isolated and characterized by IR, Raman and Mössbauer spectroscopy, EI and FAB mass spectrometry and ¹H and ¹¹⁹Sn NMR spectroscopy. The structures of Lu and [SnMe₂(H₂O)(Lu-2H)] were determined by X-ray diffraction. The crystal of [SnMe₂(H₂O)(Lu-2H)] contains dimeric [SnMe₂(H₂O)(Lu-2H)]₂ units, in which the tin atom is coordinated to the O atoms of the two deprotonated hydroxymethyl groups and one deprotonated phenolic hydroxyl group. The distorted octahedral coordination polyhedron of each tin atom is completed by a water molecule and two methyl C atoms. The butyl derivative exhibited significant in vitro antitumor activity against the human carcinoma cell lines HeLa-229, A2780 and A2780cis, although minor than that of the pyridoxine derivative prepared previously.