New Platinum(II) Triazole Thiosemicarbazone Complexes: Analysis of Their Reactivity and Potential Antitumoral Action

Abstract

The synthesis and characterization of three new platinum complexes, with 3,5‐diacetyl‐1,2,4‐triazole bis(4‐N‐isopropylthiosemicarbazone) as a ligand, are reported. The specific conditions under which solvent coordination takes place are reported and the X‐ray structure of the complex with one solvent molecule of dimethyl sulfoxide is resolved. Analysis of the reactivity of these platinum compounds aids in finding the best solution profile for biological investigations. Then, the interactions of the complexes with biological models, such as calf‐thymus DNA, are studied by using UV spectroscopy and tracking the changes in electrophoretic mobility produced in the supercoiled plasmid DNA model. Initial screening of these potential antitumoral compounds indicates possible selective antitumoral action.

Building up PtII−Thiosemicarbazone−Lysine−sC18 Conjugates

“…NMR data and the crystal structure of the complexes [Pt(apyTSCmB)Cl] and [Pt(dpyTSCmB)(CN)] (two independent molecules in the unit cell) (Figure 1) proved a square planar coordination of Pt II through the deprotonated TSC ligand (N^N^S thiolate ) and a chlorido or cyanido coligand, respectively. The two experimental structures show C−S bond lengths in the range of a single bond, whereas the C8−N3 lengths lie in the typical range of a double bond (Table 1) in line with already reported data and related structures [10,24,25,27,29] . A closer look at the angles around Pt II revealed distorted planar coordination with almost perfect Cl/C21−Pt−N2 angles of about 175 and 176°.…”

“…The results let rather conclude that there might be a dramatic influence of the linker structure that bridges the TSC with the carrier molecule (in this case sC18). This hypothesis is probably proven by the observation that we did also not detect any activity of HdpyTSCLp being structurally highly divers to recently reported toxic binuclear Pt II Cl complexes containing triazole‐bridged bisthiosemicarbazone ligands [10] . In addition, we have already seen similar effects when coupling Rh III polypyridyl complexes to sC18 [44] .…”

“…Many Pt II complexes, the most prominent being cisplatin, exhibit high anti‐proliferative activity [21–23] . This holds also true for TSC and related Pt II complexes, [10–13,23–29] which affect even cisplatin resistant cells. It is assumed that they act with high activity by a different mode of action than cisplatin [12,24,25] …”

“…Thiosemicarbazones (TSC) have been studied in the last 70 years with regard to their use as versatile ligands in coordination chemistry [1–17] with applications in transition metal catalysis, [1,4–6] and as materials for biomedical imaging and treatment [5–17] . TSCs of heterocycles, especially pyridine, form a vast group within the class of TSC.…”

Divalent manganese, cobalt, copper and cadmium complexes of (Z)‐N‐benzoyl‐N′‐(1H‐1,2,4‐triazol‐3‐yl)carbamimidothioic acid: Preparation, characterization, computational and biological studies

“…Triazole ligands and their derivatives also play a significant role as an antimicrobials, [8,9] anticancer [9] and antitumoural. [10] Due to the extensive range of biological properties [8][9][10][11][12][13][14] of triazole and thiourea derivatives, in the current study, we report the synthesis of a new carbonyl thiourea derivative and its Co(II), Cu(II), Mn(II) and Cd(II) complexes. Different modes of chelation were proposed for the metal complexes, based on the spectral and theoretical studies.…”