Iron(III) complex of 2-acetylpyrazine thiosemicarbazone: synthesis, spectral characterization, structural studies and antitumoral activity

[Fe(HL)2]Cl3 · 1.5H2O (1), where HL = C7H9N5S, 2-acetylpyrazine thiosemicarbazone, was obtained and fully characterized. X-ray diffraction studies show that complex 1 crystallizes in monoclinic lattice, space group P21 /n, with a = 11.342(6), b = 12.547(6), c = 17.056(9) Å, β = 103.551(7)°, V = 2360(2) Å3, Z = 2, Mr = 1159.46, D Calcd = 1.632 g cm−3, μ(Mo-Kα) = 1.188 mm−1, F(000) = 1184, the final R 1 = 0.0955 and wR 2 = 0.2626. The 2-acetylpyrazine thiosemicarbazone is a tridentate ligand and binds to the metal through the pyrazine nitrogen, the imine nitrogen and the sulfur in the neutral thione form yielding an octahedral geometry. The title iron complex showed significant antitumor activity against the Ec9706 human esophagus cancer cell line with an IC50 value (10.50 µM) in a micromolar range similar to cisplatin.