Novel half-sandwich iridium(III) complexes with aminomethyl(diphenyl)phosphine derived from fluoroloquinolones (IrPCp, IrPSf, IrPLm, IrPNr) were studied as possible anticancer chemotherapeutics and showed higher potency than other well-known metal-based agents i.e., Pt(II) drugs. All compounds were characterized by elemental analysis, selected spectroscopic methods (i.e., absorption and fluorescence spectroscopy, NMR), ESI-MS spectrometry, X-ray diffraction, and electrochemical techniques. The studied complexes exhibited promising cytotoxicity in vitro with IC₅₀ values significantly lower than that of the reference drug – cisplatin. The insight into the mode of action revealed the uniform distribution of the Ir(III) complexes in both the nucleus and cytoplasm (Pearson's co-localization coefficient of 0.63). Precise cytometric analysis provided clear evidence for the predominance of apoptosis in the induced cell death. The activation of caspase-3/7 along with the decrease of mitochondrial membrane potential also confirmed the apoptotic cell death. The investigated Ir(III) complexes may induce changes in the cell cycle leading to G2/M phase arrest. ROS generation as a plausible pathway responsible for the cytotoxicity was confirmed by determination of redox potentials enabling efficient ROS production. Furthermore, Pluronic P-123 micelles loaded with selected Ir(III) complexes were proposed to overcome low solubility and to minimize serious systemic side effects by administering the complex in a controlled manner. The resulting nanoformulations (IrPCp_M, IrPNr_M) facilitated efficient drug accumulation for human lung adenocarcinoma and human prostate carcinoma (A549 and DU-145 cell lines), as demonstrated by confocal microscopy and ICP-MS analysis. In vitro cytotoxicity assays were also carried out within multicellular tumor spheroids and efficient anticancer action on these 3D assemblies was demonstrated.

Copper(II) complexes with 2-ethylpyridine (1 and 2), 2-(hydroxyethyl)pyridine (3) and 2-(hydroxymethyl)pyridine (4) have been synthesized and characterized. All inorganic compounds have been studied by X-ray diffraction, thermogravimetry, vibrational and EPR spectroscopy as well as theoretical methods. The geometry of the complexes 1, 3 and 4 adopts nearly perfect geometry close to square planar (1, 4) or square pyramid (3) stereochemistry, respectively. The distortion of five coordinated copper(II) ions in complex 2 indicates intermediate geometry between square pyramidal and trigonal pyramidal geometry. Further, the magnetic measurements have shown antiferromagnetic behaviour of the prepared complexes in a wide range of temperatures. The antiferromagnetic behaviour of 2 should originate from the superexchange interactions between each copper(II) ion by the mixed chloride and μ₄-O ion pathways. Besides, the weak antiferromagnetic character of 2 can be also attributed to the presence of intrachain exchange between dimeric units through double oxide ion. In complex 3, strong antiferromagnetic coupling between Cu(II) centres in the Cu₂O₂Cl₂ moiety is found. The cytotoxicity of all compounds was tested in vitro against various cancer cell lines: human lung adenocarcinoma (A549), human breast adenocarcinoma (MCF7), human prostate carcinoma; derived from metastatic site: brain (DU-145) and two normal cell lines: human embryonic kidney (HEK293T) and human keratinocyte (HaCat). Furthermore, Pluronic P-123 micelles loaded with selected complexes (1 and 3) were proposed to overcome low solubility and to minimize systemic side effects. More detailed study revealed that complex 3 loaded inside micelles causes DU-145 cells' death with simultaneous decrease of mitochondrial membrane potential and a high level of reactive oxygen species generation. The stability of the compounds 1–4 in DMSO was confirmed by UV-Vis and FT-IR spectra studies.

A group of cytotoxic half-sandwich iridium(III) complexes with aminomethyl(diphenyl)phosphine derived from fluoroquinolone antibiotics exhibit the ability to (i) accumulate in the nucleus, (ii) induce apoptosis, (iii) activate caspase-3/7 activity, (iv) induce the changes in cell cycle leading to G2/M phase arrest, and (v) radicals generation. Herein, to elucidate the cytotoxic effects, we investigated the interaction of these complexes with DNA and serum proteins by gel electrophoresis, fluorescence spectroscopy, circular dichroism, and molecular docking studies. DNA binding experiments established that the complexes interact with DNA by moderate intercalation and predominance of minor groove binding without the capability to cause a double-strand cleavage. The molecular docking study confirmed two binding modes: minor groove binding and threading intercalation with the fluoroquinolone part of the molecule involved in pi stacking interactions and the Ir(III)-containing region positioned within the major or minor groove. Fluorescence spectroscopic data (HSA and apo-Tf titration), together with molecular docking, provided evidence that Ir(III) complexes can bind to the proteins in order to be transferred. All the compounds considered herein were found to bind to the tryptophan residues of HSA within site I (subdomain II A). Furthermore, Ir(III) complexes were found to dock within the apo-Tf binding site, including nearby tyrosine residues.

Three new Co( ii ) coordination polymers show the DC magnetic data consistent with the S = 3/2 spin system with large zero-field splitting D > 0, which was confirmed by HF EPR and FIRMS measurements.

This review highlights how a Ir(III) and Ru(II) coordination complexes can change theirs cytotoxic activity by interacting with a biomolecules such as deoxyribonucleic acid (DNA), human albumins (HSA), nicotinamide adenine dinucleotide (NADH), and glutathione (GSH). We have selected biomolecules (DNA, NADH, GSH, and HSA) based on their significant biological roles and importance in cellular processes. Moreover, this review may provide useful information for the development of new half‐sandwich Ir(III) and Ru(II) complexes with desired properties and relevant biological activities. Additionally, the examples discussed here may help us better understand what happens to a metal‐based drug once it enters the body.

We present the synthesis, physicochemical and biological activity of new Ru( ii ) and Ir( iii ) complexes ((Ru(η ⁶ - p -cymene)Cl ₂ PPh ₂ CH ₂ OH, Ru(η ⁶ - p -cymene)Cl ₂ P( p -OCH ₃ Ph) ₂ CH ₂ OH), (Ir(η ⁵ -Cp*)Cl ₂ P( p -OCH ₃ Ph) ₂ CH ₂ OH, Ir(η ⁵ -Cp*)Cl ₂ PPh ₂ CH ₂ OH).