Half-sandwich ruthenium-arene thiosemicarbazones complexes: Synthesis, characterization, biological evaluation and DFT calculations

Three new conformationally rigid half-sandwich organoruthenium(II) complexes having compositions [(eta 6-p- cymene)Ru(TLS)Cl]Cl (1), [(eta 6-p-cymene)Ru(TLSM)Cl]Cl (2) and [(eta 6-p-cymene)Ru(TLSN)Cl]Cl (3) have been synthesized by reacting [{(eta 6-p-cymene)RuCl}2(mu-Cl)2] with respective thiosemicarbazones-2-acetylpyridin-N (4)-phenylthiosemicarbazone (TLS), 2-acetylpyridineN(4)-methylthiosemicarbazone (TLSM) and 2-acetylpyri-dine-N(4)-thiosemicarbazone (TLSN). The newly synthesized complexes have been characterized by elemental analysis, UV-Vis, FT-IR and 1H and 13C NMR spectroscopy. The geometry optimizations for all three complexes confirmed the distorted tetrahedral piano-stool type geometry around Ru(II) which is further coordinated to azomethine nitrogen and thione sulphur centers. Apart from geometry optimizations, the Gibbs free energy calculations, frontier molecular orbital parameters, molecular electrostatic potential (MEP) values as well as the bond order have been computed for these complexes. Also, the newly synthesized complexes have been screened for their anti-mycobacterial and anticancer activities.