Importance of the π-Ligand: Remarkable Effect of the Cyclopentadienyl Ring on the Cytotoxicity of Ruthenium PTA Compounds

Abstract

The water-soluble complexes [(Cp′OR)RuCl(PTA) 2 ] (Cp′OR ) η 5 -1-alkoxy-2,4-di-tert-butyl-3-neopentylcyclopentadienyl; R ) Me, Et; PTA ) 1,3,5-triaza-7-phosphaadamantane) are considerably more cytotoxic (ca. 2 orders of magnitude) than the cyclopentadienyl analogue [CpRuCl(PTA) 2 ] (i.e., IC 50 ) 4-10 Vs >1000 µM, depending on the cell line). The structure of [(Cp′OMe)RuCl(PTA) 2 ] is reported, together with that of the precursor [(Cp′OEt)Ru(µ-Cl)] 2 .

Contributions to the Chemistry of the Cyclopentadienyl Complex [Cp∧RuCl2]2 (“Cp‐roof” = η5‐1‐Methoxy‐2,4‐tert‐butyl‐3‐neopentylcyclopentadienyl)

“…[1a,3] Cp ∧ Ru complexes were also shown to display a unique behavior in catalytic reactions [3,4] and in biological assays. [5] Below, we describe novel reactions of complex 1. We will detail the syntheses and the structures of complexes with carbene, imido, and orthometalated phosphine ligands, as well as the microwave-assisted syntheses of the bimetallic complexes [Cp ∧ Ru(μ-Cl) 3 Ru(p-cymene)] and [Cp ∧ Ru(μ-Cl) 3 RhCp*].…”

Studies on the interactions of a novel ruthenium(II) complex with G-quadruplex DNA

“…It has been found that ruthenium(II) complexes with large aromatic ligands can intercalate into the base pairs of the DNA helixes, and the binding affinity increases when there are intramolecular hydrogen bonds and/or electron-withdrawing groups in the intercalating ligand [9][10][11][12][13][14][15]. However, few ruthenium(II) complexes with high antitumor activity have been reported so far, and this is attributed to the low lipid/water partition coefficients of these complexes [16][17][18], which prevent them from crossing the cell membrane.…”

Mass spectrometry and UV‐VIS spectrophotometry of ruthenium(II) [RuClCp(mPTA)2](OSO2CF3)2 complex in solution

“…Ruthenium compounds are now of high interest in biology and medicine due to their great cancerostatic activity 1,2 and because they show lower toxicity than platinum compounds. 3 As ruthenium can mimic iron in binding serum proteins (such as transferrin or albumin), the ruthenium compounds interact with DNA 4 and are therefore prospective anticancer drugs even if, in contrast to Pt-based drugs, the mechanisms of the activity of Ru-based compounds are still not well known and/or understood. 5,6 Promising alternatives to platinum anti-tumour drugs in the treatment of cancer 7,8 are those ruthenium compounds which have as ligand water-soluble phosphines, such as, 1,3,5-triaza-7-phospha-adamantane (PTA), for example.…”