Abstract: A series of bis{oxo-bis[heteroaromatic carboxylatodibenzyltin(Ⅳ)]} complexes {[(PhCH₂)₂Sn·(O₂CR)]₂O}₂[where R=2-furyl, 2-(2-furyl)vinyl, 2-(5-tert-butyl)furyl, 2-thiophenyl, 2-pyridinyl, 3-pyridinyl, 4-pyridinyl, 3-indolyl, 3-indolylmethyl, 3-indolylpropyl] was synthesized by the reactions of heteroaromatic carboxylic acids with dibenzyltin(Ⅳ) oxide. All the complexes were characterized by elemental analysis, IR, and NMR spectra. The complexes were tested against two human tumour cell lines: MCF-7 and WiDr. The results show that they have higher activities in vitro. The crystal structure of bis{oxo-bis[2-furylcarboxylatodibenzyltin(Ⅳ)]}(1) was determined by X-ray diffraction. The crystal belongs to monoclinic space group P2₁/n, a=1.6641(2) nm, b=1.25073(18) nm, c=1.7193(3) nm, β=101.951(2)°, Z=2, R₁=0.0446, wR₂=0.1100. Complex 1 is of a centrosymmetric dimer structure with a four-membered central endo-cyclic Sn₂O₂ unit in which the bridged oxygen atoms are tri-coordinated. Each bridged oxygen atom also connects with an exo-cyclic tin atom. The tin atoms are six-coordinated and have a coordination geometry of a distorted octahedron. The exo-cyclic tin atoms are five-coordinated and have a coordination geometry of a monocapped trigonal bipyramid with a very similarly distorted mode. Four carboxylate ligands are divided into two types. The two of the four carboxylate ligands are bidentate and bridged to each pair of exo- and endo-cyclic tin atoms by using both the oxygen atoms. The other two are monodentate and bridged to each pair of exo- and endo-cyclic tin atoms but each utilizes one O atom only.

Key words: Dibenzyltin(Ⅳ), Heteroaromatic carboxylate, Biological activity, Crystal structure