On the bioreactivity of triorganotin aminobenzoates. Investigation of trialkyl and triarylyltin(IV) esters of 3-amino and 4-aminobenzoic acids

The synthesis and study of trimethyl-, tributyl- and triphenyltin esters of the 3- and 4-aminobenzoic acids are reported. The triorganotin derivatives are characterized by elemental analyses, FT-IR and solution ¹H and ¹³C NMR spectra. The structure of the trimethyltin 4-aminobenzoate is solved by X-ray diffraction and proves to be polymeric in nature with bridging carboxylates and trigonal bipyramidal tin(IV) environment. However, all the compounds become monomeric in solution with a tetrahedral tin coordination environment in chloroform and trigonal bipyramidal in DMSO due to coordination of the solvent as the NMR spectra have revealed. The compounds exhibit variable cytotoxic activity when tested against Κ562 myelogenous leukaemia, HeLa cervical cancer and HepG2 hepatocellular carcinoma cell lines, with the butyl derivatives being the more effective and the methyl ones the less. Interestingly, their antibacterial action was significantly lower when tested against Escherichia coli, while not appreciable direct interaction with DNA has been observed. The above observations account for a mode of action that may be related to their potential interaction with cell membranes and the subsequent inhibition of various signaling processes.     

Syntheses and characterization of triorganotin(IV) complexes of Schiff base derive from 4-amino-5-phenyl-4H-1,2,4-triazole-3-thiol and 5-amino-1,3,4-thiadiazole-2-thiol with p-phthalaldehyde

Eight triorganotin complexes of the types [(R₃Sn)₂(C₂₄H₁₆N₈S₂)].Y (R = Ph, Y = 0 (1); R = PhCH_2, Y = 2CH₃OH (2); R = n-Bu, Y = 0 (3)), [(R₃Sn)₂(C₂₄H₁₆N₈S₂)]_n (R = Me (4)), [(R₃Sn)₂(C₁₂H₆N₆S₄)] · Y (R = Ph, Y = CH₂Cl₂ (5); R = PhCH_2, Y = 0 (6)) and [(R₃Sn)₂(C₁₂H₆N₆S₄)] (R = Bu (7), R = Me (8)) have been obtained by H₂L₁ (H₂L₁ derived from 4-amino-5-phenyl-4H-1,2,4-triazole-3-thiol) and H₂L₂ (H₂L₂ derived from 5-amino-1,3,4-thiadiazole-2-thiol) with triorganotin chloride in the presence of sodium ethoxide. All the complexes were characterized by elemental, IR and NMR spectra analyses, except for complexes 1, 3, 6 and 8, other complexes were also characterized by X-ray diffraction analyses, which reveal that complexes 2 and 5 are dinuclear structures, complex 4 has a 2D network structure and complex 7 forms a macrocyclic structure linked by intermolecular N → Sn interactions.     

Triorganotin(IV) complexes of Schiff base derived from 6-amino-2-mercaptobenzothiazole: Synthesis, characterization and X-ray crystal structures

Nine triorganotin(IV) complexes of the type R₃SnL (L = L1 R = Me 1, Ph 2, PhCH₂3; L = L2 R = Me 4, Ph 5, PhCH₂6; L = L2 R = Me 7, Ph 8, PhCH₂9) have been obtained by reaction of new Schiff base HL1, HL2 or HL3 with triorganotin(IV) chloride in the presence of sodium ethoxide. All the complexes 1-9 were characterized by elemental, IR and NMR spectra analyses. Except for complexes 3, 4, 6, 9, the others were also characterized by X-ray crystallography diffraction analyses, which revealed that complexes 1, 2, 5, 7, 8 were four coordinated and displayed a capped tetrahedron.     

The structural chemistry of triorganotin(IV) derivatives of 3-amino-5-mercapto-1,2,4-triazole: Supramolecular structures involving intermolecular N-H?N and N-H?S hydrogen bonding

Four new triorganotin complexes of 3-amino-5-mercapto-1,2,4-triazole with the type of R₃Sn(SC₂N₃HNH₂-3) (R = Me, 1; n-Bu, 2; Ph, 3; PhCH₂, 4) have been synthesized. All the complexes have been characterized by elemental analysis, IR, ¹H NMR and ¹³C NMR spectra. Complexes 1, 3 and 4 have been characterized by X-ray crystallography analyses too. The geometry about Sn of complex 1 is distorted trigonal bipyramidal and the supramolecular structures of complex 1 has been found consist of channels built up by intermolecular N-H?N hydrogen bonding. The geometry of tin atoms in complexes 3 and 4 are distorted tetrahedron and 1D polymers connected by intermolecular N-H?N hydrogen bonding or N-H?N and N-H?S hydrogen bonding. Additionally, 1D polymer of complex 3 aggregated in 2D layer by intermolecular N-H?S hydrogen bonding.     

Synthesis, characterizations, and crystal structures of triorganotin(IV) derivatives with areneseleninic acids

Six new triorganotin(IV) complexes, [R₃Sn(O₂SeC₆H₄Cl)]_n (R = Me 1; Ph 2), [R₃Sn(O₂SeC₆H₄Me)]_n (R = Me 3; Ph 4), [R₃Sn(O₂SeC₆H₄Bu)]_n (R = Me 5; Ph 6) have been synthesized by the reaction of 4-chlorobenzeneseleninic acid, p-Tolueneseleninic acid, and 4-tert-butylbenzeneseleninic acid with triorganotin(IV) chloride in the presence of sodium ethoxide. All of the complexes were characterized by elemental analysis, FT-IR, NMR (¹H, ¹³C, and ¹¹⁹Sn) spectroscopy, and X-ray crystallography. Crystal structures show that all of the complexes exhibit 1D infinite chain structures which are generated by the bidentate oxygen atoms and the five-coordinated tin centers.     

Spectral analysis and in vitro cytotoxicity profiles of novel organotin(IV) esters of 2-maleimidopropanoic acid

Six novel triorganotin(IV) 2-maleimidopropanoato complexes: R₃SnOCOCH₃(CH)(COCH)₂, (R: Me(1), Et(2), n-Pr(3), n-Bu(4), Ph(5), Bz(6) have been synthesized. Their solid-state configuration has been determined by FT IR and ^119mSn Mössbauer spectroscopy. The tin(IV) atom is five-coordinated in all the complexes with 2-maleimidopropanoic acid behaving as a monoanionic bidentate ligand coordinating the tin(IV) atom through a chelating or bridging carboxylate group. The solution-state configuration has been elucidated by means of ¹H-, ¹³C- and ¹¹⁹Sn-NMR spectroscopy which assigned a tetrahedron. Elemental analysis and FAB MS data also supported a 1:1 metal to ligand stoichiometry. The title complexes have been screened in vitro for anti-tumour, anti-fungal, anti-leishmanial and urease inhibition activities and displayed promising results.     

Novel triorganotin(IV) complexes of β-diketonates bearing two heterocycles in their structures

Novel triorganotin(IV) derivatives of β-diketonate Q ligands (HQ in general, in detail HQ^fur = 1-phenyl-3-methyl-4-(2-furancarbonyl)-pyrazol-5-one, HQ^thi = 1-phenyl-3-methyl-4-(2-thienylcarbonyl)-pyrazol-5-one) of general formula (Q)SnR₃·xH₂O (R = Ph, x = 0; R = Buⁿ or Me, x = 1) have been synthesized and spectroscopically and thermally characterized. Triphenyltin(IV) complexes have been isolated as anhydrous compounds while trialkyltin(IV) are always monohydrated. The structures of (Q^fur)SnPh₃ and (Q^thi)SnMe₃(OH₂) are recorded. The tin atoms are five-coordinate in both. In the first, the pyrazolonate ligand behaves as an O,O′-bidentate; there are two similar but independent molecules in the structure. In the quasi-trigonal-bipyramidal environments, Sn-O(acyl) are 2.478(3), 2.364(3), Sn-O(pyrazolonate) 2.050(2), 2.079(2), Sn-C 2.123(4)-2.162(3) Å with the longer O(acyl) and a phenyl group quasi-trans (O-Sn-C 162.5(1), 160.8(1)°). In (Q^thi)SnMe₃(OH₂), the three methyl groups are equatorial (Sn-C 2.1259(9)-2.1380(8) Å); Sn-O(Q^thi,OH₂) are 2.2143(5), 2.3350(6) Å, O-Sn-O 175.36(2)°. Trimethyltin(IV) derivatives decompose on heating with release of H₂O and SnMe₄ and formation of (Q)₂SnMe₂. Decomposition occurs also within two days after dissolution of (Q)SnMe₃(OH₂) in chloroform.