Synthesis and structure of a novel trinuclear 18-membered macrocycle of diphenyltin complexes with 2-mercaptonicotinic acid

The 18-membered stereoregular diphenyltin macrocycles: {Ph2Sn[S(C6H3NO)O]}3 (8), {Ph2Sn[S(C6H3NO)O]}3·2.67H2O (9) and {Ph2Sn[S(C6H3NO)O]}3·4C6H6 (10) have been synthesized by the reaction of diphenyltin dichloride with 2-mercaptonicotinic acid. The three complexes were characterized by elemental, IR, 1H-NMR analyses. The X-ray crystallography analyses of 9 and 10 were also given. Single crystal X-ray diffraction data reveal that both 9 and 10 are highly symmetrical tri-nuclear cyclic complexes with the ligand 2-mercaptonicotinic acid bridging the adjacent tin atoms. The tin environment is distorted cis-trigonal bipyramid. Weak interaction Sn⋯O was recognized between tin and exocyclic-oxygen atoms. The potential tridentate of endocyclic sulfur atoms make them interesting ligands.