Synthesis, crystal structure, and bioactivity of two triphenylantimony derivatives with benzohydroxamic acid and N-phenylbenzohydroxamic acid

Reaction of triphenylantimony dichloride with benzohydroxamic acid or N-phenylbenzohydroxamic acid in 1 : 1 stoichiometry yielded two new triphenylantimony derivatives formulated as [Ph3SbL1L2] (L-1 = benzohydroxamato, L-2 = methoxide, 1; L-1 = N-phenylbenzohydroxamato, L-2 = Cl, 2), which have been characterized by FT-IR, NMR spectroscopy, elemental analysis, and melting point. Single-crystal X-ray diffraction analyses for 1 and 2 reveal that the antimony is six-coordinate adopting distorted octahedral geometry with one phenyl and methoxide or chloride in axial positions. In the supramolecular structure, a double-chain is shown for 2 constructed by C-H center dot center dot center dot X (X = O, C or pi) weak interactions, while 1 exhibits a 1-D-chain structure connected by O-H center dot center dot center dot O and N-H center dot center dot center dot N hydrogen bonds. In vitro antitumor study reveals that 1 and 2 display activities against two human tumor cell lines - A549 and HCT-8. To explore the antitumor activity mechanism, DNA binding properties of 1 and 2 with calf thymus DNA (ct-DNA) have been investigated by fluorescence spectra, indicating that 1 and 2 bind to ct-DNA via intercalation, which could induce the death of cancer cells.