Synthesis, characterisation, and structural elucidation by spectral investigation (FT-IR, multinuclear NMR, mass spectrometry) of biologically active organotin(IV) compounds containing germanium

Authors: MUHAMMAD KALEEM KHOSA, MUHAMMAD MAZHAR, SAQIB ALI, SARIM DASTGIR

Abstract: A new series of di and tri-organotin(IV) compounds containing germanium with the general formula R_{4-n}SnL_n was synthesised by reaction of 3-triphenylgermanyl-3,3-dimethylpropionic acid with organotin(IV) oxides and organotin(IV) chloride in 2:1 and 1:1 molar ratio, respectively, where R~=~CH_3, C_2H_5, n-C_4H_9, n-C_8H_{17}, and C_6H_5 n = 1 or 2 and L~=~triphenylgermanyl acid anion (GeC_{23} H_{23} O_2^-). These compounds were characterised by elemental analyses, FT-IR, multinuclear NMR (^1H, ^{13}C, ^{119}Sn), and mass spectrometry. The geometry around the tin atom was determined and compared in both solution and solid states. The spectroscopic results indicated that all the diorganotin(IV) compounds containing germanium possess trigonal-bipyramidal structures in solution and octahedral geometry in the solid state. A linear polymeric trigonal-bipyramidal structure in the solid state and a tetrahedral environment around the tin atom in non-coordinating solvents has been proposed for the triorganotin(IV) compounds. All synthesised compounds were tested in vitro against a number of microorganisms to assess their biocidal properties and to correlate them with the structures of the derivatives. These studies revealed that such compounds show promising activity against different strains of bacteria and fungi using the reference drugs imipenum and miconazole.

Keywords: Bimetallic organotin, germanium carboxylates, microbibial activity.

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