Synthesis, crystal structure and biological activities of the novel dimacrocyclic di-n-butyltin carboxylates

4-(1, 2-Dithiopropylene) methylene-3, 5-dioxo-1, 6-heptadiene-1, 7-di-o-phenoxyacetic acid (1) was synthesized through the reaction of 3-(1, 2-dithiopropylene) methylene-2, 4-dioxo pentane with 2-formyl-phenoxyacetic acid under the catalysis of sodium ethoxide. The new di-n-butyltin carboxylate complex 2 was synthesized by the reaction of the complex 1 with di-n-butyltin oxide. Ligand 1 and complex 2 were characterized via elemental analysis, ¹H NMR, IR and X-ray single crystal diffraction. The structure of complex 2 is a centrosymmetric dimer built up around the rhombus cyclic Sn₂O₂ four-membered ring, and the rhombus ring joins two exo-cyclic Sn atoms by O atoms. Each carboxyl group was coordinated with endo- and exo-cyclic Sn atoms respectively forming two symmetric six-membered ring. The three rings are in trapezoidal arrangement dividing the complex 2 into two big symmetric twenty-two membered ring. The complex shows antibiotic and anti-tumour activities in vitro experiments.