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Triorganotin(IV) complexes of azo-carboxylic acids derived from amino benzoic acids and resorcinol were synthesized by the reaction of 2/4-(2,4-dihydroxy-phenylazo)-benzoic acids with appropriate triorganotin(IV) chlorides [R = Me (1 and 3), Ph (2 and 4) and Bu (5)] in presence of triethylamine. The characterisation of the complexes was accomplished by elemental analyses, UV, IR and multinuclear (1H, 13C and 119Sn) NMR spectroscopy. Structure of compound 3 was established by X-ray crystal structure analysis. X-ray crystal structure of 3 revealed that the compound exhibits a 48 membered macrocyclic-tetrameric structure with trigonal bipyramidal geometry around the tin atoms in which the three methyl groups occupy the equatorial positions while the apical positions are being occupied by the oxygen atom of carboxylate group of one ligand and the phenoxide oxygen atom of another ligand. The coordination network in 3 has also been analysed from the topological viewpoint. All the complexes display a sharp singlet 119Sn resonance in the range specified for the four coordinate structures suggesting that complexes have tetrahedral structures in solution. The five coordinate structure of the complexes in solid state dissociated into monomeric species with four coordinate structures in solution. Anti-diabetic activities of the complexes were studied and the results showed that the compounds 2, 3 and 4 exhibited effective activity even higher than the standard compound.

Three new organotin(IV) complexes 1–3 were synthesized by the reaction of 2-(4-hydroxynaphthylazo)-benzoic acid with bis-tributyltin(IV) oxide (1), dibutyltin(IV) oxide (3) or trimethyltin(IV) chloride (2), respectively. The complete characterization of the complexes was accomplished by elemental analysis, IR and multinuclear [1H- and 13C- and 119Sn-] NMR spectroscopy. The crystal structures of all the complexes were elucidated with the help of X-ray single crystal diffraction analysis. The geometry around tin atoms in 1 and 2 was trigonal bipyramidal geometry where the equatorial plane was occupied by the three alkyl groups (Bu or Me) and the axial positions in 1 were being occupied by carboxylate and phenoxide oxygen atoms giving rise to a polymeric structure. In 2, a hydroxy oxygen atom bridges two tin atoms occupying axial position while the other axial positions in each tin atom were being occupied by a carboxylate oxygen atom or oxygen atom of a water molecule respectively thereby completing trigonal bipyramidal geometry. The structure of 3 was a di-nuclear complex with six-coordinate distorted skew trapezoidal and seven-coordinate pentagonal bipyramidal geometry around the tin atoms, respectively. In the dinuclear structure, one of the tin atoms is coordinated by a terminal azo-ligand while the other tin atom is coordinated by two terminal azo-ligands. In addition to this, another azo-carboxylate ligand bridges the two atoms in the dinuclear structure. The NMR study showed that in the solution the complexes 1 and 2 adopted four-coordinate geometry, while in 3 there is five-coordinate structure. Complexes 1 and 3 were screened for their antidiabetic activities against α-glucosidase enzyme and results of the assay found that compound 3 exhibited significant inhibition activity.

Triorganotin (IV) complexes 1–3 were synthesized by the reaction of azo-carboxylic acid viz. 2/4-(2-hydroxynaphthylazo)benzoic acids with appropriate triorganotin(IV) chlorides [R = Me (compounds 1 and 2) and Bu (compound 3)] in presence of triethyl amine base. The complexes were characterized by elemental analysis, IR and multinuclear (1H and 13C- and 119Sn)-NMR spectroscopy. The structures and mode of coordination around tin ions in the complexes were determined by single crystal X-ray crystallography. The complexes exhibit trigonal bipyramidal geometry around tin atoms where the base of the equatorial plane is being occupied by the three alkyl groups [Me or Bu] while the axial positions are occupied by carboxylate oxygen atoms in 2 and in case of 1 and 3, by carboxylate and phenoxide oxygen atoms, respectively. It has been found that, the crystal structure of 1 or 3 is a cyclic dimeric, whereas 2 exhibits a polymeric structure. The 119Sn NMR studies show that all complexes have four-coordinate structures indicating dissociation of these complexes in solution state. The complexes were also screened for their antimicrobial activity and the compound 3 was found to exhibit effective antimicrobial activity.