Cytotoxic oxidovanadium(IV) complexes of tridentate halogen‐substituted Schiff bases: First dinuclear V(IV) complexes with O → VIV = O → VIV = O core

Structural features and antiproliferative activity of Pd(ii) complexes with halogenated ligands: a comparative study between Schiff base and reduced Schiff base complexes

“…This test also highlights the relevant impact of halogen substitution on the biological activity profile of the ligands, as the corresponding non-halogenated derivatives of both chemical classes have shown negligible cytotoxicity in previous reports. 13,43…”

“…According to the strategies mentioned above, we recently obtained a series of copper(II)and vanadium-based complexes from 3,5-halogen-substituted ligands. [12][13][14] In the Schiff basetype Cu(II) complexes, the Cu(II) ion is four-coordinated and has a distorted square-planar coordination sphere in which three positions are occupied by one phenolate oxygen, one imine nitrogen and one pyridine-N atom of the mono-negative tridentate Schiff base ligand, respectively, forming five-and six-membered chelate rings, while the other position is derived from a coordinated ion (NO − 3 or Cl − ). In complexes with such ligands in reduced form the structure is similarly distorted square-planar, but the ligand acts as a bidentate ligand through the aminic and the pyridinic nitrogen atoms.…”

“…This test also highlights the relevant impact of halogen substitution on the biological activity profile of the ligands, as the corresponding non-halogenated derivatives of both chemical classes have shown negligible cytotoxicity in previous reports. 13,43 The top two compounds, i.e. the reduced-type ligand Cl 2 Pic (R) and complex Br 2 Pic(R)Pd, were selected for IC 50 determination and resistance ratio calculations.…”

“…Padeliporfin, as a di-potassium salt, was approved for use in the European Union in November 2017 (brand name Tookad®) for the treatment of prostate cancer, while padoporfin reached phase II clinical trials. 9 Following the encouraging results of our previous research studies dealing with metal complexes endowed with antiproliferative activity, [10][11][12][13][14][15][16][17][18][19][20][21] we decided to move on with the design and synthesis of new Pd(II) complexes starting from previously synthesized asymmetric halogen-substituted ligands. 12 In this context, we prepared five Schiff base and six reduced Schiff base Pd(II) complexes with the abovementioned ligands in order to investigate their anticancer activity and propose them as possible drug candidates or new lead structures for future drug design.…”