Cyclometalated Complexes of Platinum and Palladium with N-(4-Chlorophenyl)-α-benzoylbenzylideneamine. In Vitro Cytostatic Activity, DNA Modification, and Interstrand Cross-Link Studies

Abstract

In the present paper we report the synthesis and structural IR and 1H and 13C NMR characterization of four platinum(II) and palladium(II) cyclometalated complexes of the formula [Pd(4-ClC6H4NC(COC6H5)C6H4)X]2, where X = OAc (2) or Cl (3), and [Pt(4-ClC6H4NC(COC6H5)C6H4)X]2, where X = Cl (4) or OAc (5). The acetate-bridged compounds 2 and 5 have an open-book structure. The chloro-bridged compounds 3 and 4 have an unfolded structure. Complex 2 crystallizes in the centrosymmetric triclinic space group P1̄, with Z = 2. Unit cell parameters are as follows: a = 11.765(3) Å, b = 12.862(4) Å, c = 15.022(5) Å, α = 84.08(2)°, β = 78.56(2)°, γ = 83.13(2)°. All these compounds were screened against MDA-MB 468 (breast carcinoma) and HL-60 (leukemic) tumor cells. The low IC50 values of compound 5 (1.05 μM) and of compound 4 (1.58 μM) against MDA-MB 468 and of 0.82 μM (5) and 1.37 μM (4) against HL-60 relative to cis-DDP (2.67 and 2.07 μM, respectively) and other cyclometalated compounds suggest that the synthesized compounds may be regarded as having potential antitumor properties. The data suggest that the antiproliferative activity of compound 5 may correlate with its covalent binding to DNA and the induction of important modifications on the helix.

The First Crystal and Molecular Structure of asyn-Acetato-Bridged Dinuclear Cyclometallated Complex [Pd{2,3,4-(MeO)3C6HC(H)=NCH2CH2OH}(μ-OAc)]2

“…[1Ϫ7] They are important not only because they show numerous applications in organic and organometallic synthesis [8] and in biologically active compounds, [9,10] among others, but also due to the new structural features they promote. [11,12] Lately, we have been interested in the study of Schiff base cyclometallated complexes prepared by direct reaction of the ligand with palladium() bridged complex 3 with PPh 3 in acetone yielded the mononuclear complex 8, and reaction of 3 with silver triflate gave the cyclometallated complex 9, with the palladium atom bonded to four different atoms C, N, O and P. Treatment of 3 with the tertiary diphosphanes dppp, dppb and dppf, in a 1:1 molar ratio gave the dinuclear complexes 10, 11 and 12, respectively, with terminal chloride ligands.…”

Palladium(II) Schiff Base Complexes Derived from Allylamine and Vinylaniline

“…For instance, related Pd(II) benzoylbenzylideneamine derivatives display high antitumor activity towards certain forms of cancer. 20 Addition of allylamine to salicylaldehydes gives compounds having NMR and FT-IR spectroscopic data consistent with the corresponding salicylaldimines. For example, for the parent salicylaldehyde compound a singlet at δ 8.33 ppm is observed in the 1 H NMR spectra for the imine methine peak and the diagnostic C=N stretching band is found in the FT-IR spectra at 1620 cm H NMR spectra is observed for the imine methine proton upon coordination of the ligand to the metal centre.…”

New pH-dependent complexes, from mononuclear Pd(II) monomer to heteronuclear [Pd(II),K(I)]Polymer: DNA cleavage and cytotoxicity in vitro

“…The two complexes were consistently more active than cisplatin against the HL-60 cells, and A2780 cisR cells, exhibiting a high level of resistance against some other Pd(II) complexes [36][37][38][39]. A viability rate by day 2 to less than 50% of the control values was observed for the complexes.…”