Antineoplastic Activity of New Transition Metal Complexes of 6‐Methylpyridine‐2‐carbaldehyde‐N(4)‐ethylthiosemicarbazone: X‐Ray Crystal Structures of [VO2(mpETSC)] and [Pt(mpETSC)Cl]

New complexes of dioxovanadium(V), zinc(II), ruthenium(II), palladium(II), and platinum(II) with 6-methylpyridine-2-carbaldehyde-N(4)-ethylthiosemicarbazone (HmpETSC) have been synthesized. The composition of these complexes is discussed on the basis of elemental analyses, IR, Raman, NMR ((1)H, (13)C, and (31)P), and electronic spectral data. The X-ray crystal structures of [VO(2)(mpETSC)] and [Pt(mpETSC)Cl] are also reported. The HmpETSC and its [Zn(HmpETSC)Cl(2)] and [Pd(mpETSC)Cl] complexes exhibit antineoplastic activity against colon cancer human cell lines (HCT 116).