Synthesis, Characterization, and Biological Investigation of Antimony(III) Halide Complexes With Different Coordination Architectures Constructed From Thiophene Thiosemicarbazones

Abstract

In this study, we report the synthesis, characterization, and biological investigation of antimony(III) halide complexes with various coordination architectures constructed from thiophene thiosemicarbazones. Antimony(III) thiophene-2-carbaldehyde thiosemicarbazone complexes (1, 2, 4, and 5) exhibit a square pyramidal geometry, with ligands coordinated to the central antimony atom in two distinct binding modes. In contrast, antimony(III) 2-acetylthiophene thiosemicarbazone complexes (3, 6, and 7) adopt a seesaw geometry. These complexes (1–7) represent the first reported examples of antimony(III) halide thiosemicarbazone compounds. The unique coordination environments observed in these complexes are of significant importance within the realm of antimony chemistry. These synthesized complexes exhibit different coordination geometries as well as potential biological activities. The antiproliferative activity against the human breast adenocarcinoma (MCF-7) cell line and antimicrobial activity against Gram-positive and Gram-negative bacteria were assessed. Antimony(III) thiophene-2-carbaldehyde thiosemicarbazone complexes (1, 2, 4, and 5) showed significant antiproliferative activity with IC50 values ranging from 8.5 to 19.1 μM, while antimony(III) 2-acetylthiophene thiosemicarbazone complexes (3, 6, and 7) had higher IC50 values. Additionally, the antimony complexes demonstrated selective antimicrobial activity against Gram-negative bacteria.