Synthesis and structure of a novel tetranuclear 32-membered macrocycle of triphenyltin complex with pyridine-4-carboxylic acid N-oxide

The 32-membered stereoregular triphenyltin macrocycle: [Ph₃Sn (OCOC₅H₄NO)]₄·3(CH₂Cl₂) has been synthesized by the reaction of triphenyltin chloride with pyridine-4-carboxylic acid N-oxide. The complex was characterized by elemental analysis, FT-IR, NMR (¹H, ¹¹⁹Sn) spectra and X-ray crystallography. Single crystal X-ray diffraction data reveal that the complex is highly symmetrical tetranuclear cyclic complex with the ligand pyridine-4-carboxylic acid N-oxide bridging the adjacent tin atoms. All four tin atoms are five-coordinated resulting in trigonal bipyramidal geometry. And the complex showed good thermal stability and high antitumor activity.