Cyclometalated rollover complexes of the type [PtMe(κ N,C-bipyO-H)(L)] [bipyO-H=cyclometalated 2,2'-bipyridine N-oxide; L=tricyclohexylphosphine (PCy , 2 a), 2-(diphenylphosphino)pyridine (PPh py, 2 b), P(OPh) (2 c)] were synthesized by treating [PtMe(κ N,C-bipyO-H)(SMe )] (1) with various monodentate phosphine and phosphite ligands. These complexes were characterized by NMR spectroscopy, and the structure of 2 a was confirmed by single-crystal X-ray diffraction. Complex 1 was treated with bis(diphenylphosphino)methane (dppm) at a 1:1 ratio to give the corresponding [PtMe(κ N,C-bipyO-H)(κ P-dppm)] (3 b) complex, in which the dppm ligand acts as a monodentate pendant ligand. The biological activities of these complexes were evaluated against a panel of four standard cancer cell lines: lung carcinoma (A549), ovarian carcinoma (OV-90 and SKOV3), and breast carcinoma (MCF-7). Complexes 2 c and especially 3 b indicated effective potent cytotoxic activity regarding the cell lines. Electrophoresis mobility shift assays and molecular-modeling investigations were performed to determine the specific binding mode and the binding orientation of these alkylating agents to DNA. Detection of cellular reactive oxygen species was also determined.

Half-lantern Pt(ii) and Pt(iii) cyclometalated binuclear complexes, bridged with various heterocyclic thiolate ligands, were synthesized and studied by electrochemical and photophysical techniques.

Complex 1 was reacted with different alkyl halides at room temperature. This reaction proceeded via formation of binuclear intermediate complex 3 and through C–S bond reductive coupling to produce alkyl sulfides and corresponding halide complexes 2.

The known cyclometalated platinum(II) complex [Pt(ppy)(DMSO)(Cl)] (A) in which ppy = 2‐phenylpyridinate, was treated with 2‐(diphenylphosphino)pyridine (PPh2py, PN) (1 equiv.) and readily afforded complex [Pt(ppy)(PPh2py‐κ1P)(Cl)] (1). The transphobia effect (T) and single‐crystal X‐ray diffraction crystallography confirmed that the phosphine ligand in 1 is located trans to the nitrogen atom of the cyclometalating fragment (ppy). Compound 1 was treated with various thiolate reagents (1 equiv.) at room temperature, leading to the displacement of the chloride ligand in 1 by thiolate ligands through a salt metathesis reaction. The reaction led to the formation of a series of monomeric complexes with the general formula [Pt(ppy)(PPh2py‐κ1P)(SR)] (2a–2d), where SR = deprotonated form of pyridine‐2‐thiol (HSpy, 2a), pyrimidine‐2‐thiol (HSpyN, 2b), thiophenol (HSPh, 2c), and 2‐thiazoline‐2‐thiol (HSt, 2d). All complexes have been characterized by NMR spectroscopy. The biological activities of the complexes were evaluated against three human cancer cell lines, including A549 (human lung cancer), SKOV3 (human ovarian cancer), and MCF7 (human breast cancer), by means of the MTT assay [MTT = 3‐(4,5‐dimethylthiazol‐yl)‐2,5‐diphenyltetrazolium bromide]. Compounds 2a and 2b presented effective, potent cytotoxic activity regarding the cell lines. Electrophoretic mobility shift assays on plasmid DNA and molecular modeling investigations were also performed to determine the specific binding mode or the binding orientation of the complexes to DNA.

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The preparation and characterization of new heteronuclear-platinum(ii) complexes containing a 1,1'-bis(diphenylphosphino)ferrocene (dppf) ligand are described. The reaction of the known starting complex [PtMe(κN,C-bipyO-H)(SMe)], A, in which bipyO-H is a cyclometalated rollover 2,2'-bipyridine N-oxide, with the dppf ligand in a 2 : 1 ratio or an equimolar ratio led to the formation of the corresponding binuclear complex [PtMe(κN,C-bipyO-H)(μ-dppf)], 1, or the mononuclear complex [PtMe(κC-bipyO-H)(dppf)], 2, respectively. According to the reaction conditions, the dppf ligand in 1 and 2 behaves as either a bridging or chelating ligand. All complexes were characterized by NMR spectroscopy. The solid-state structure of 2 was determined by the single-crystal X-ray diffraction method and it was shown that the chelating dppf ligand in this complex was arranged in a "synclinal-staggered" conformation. Also, the occurrence of intermolecular C-HO interactions in the solid-state gave rise to an extended 1-D network. The electronic absorption spectra and the electrochemical behavior of these complexes are discussed. Density functional theory (DFT) was used for geometry optimization of the singlet states in solution and for electronic structure calculations. The analysis of the molecular orbital (MO) compositions in terms of occupied and unoccupied fragment orbitals in 2 was performed.

Reaction of PPh3 with half-lantern complex [{Pt(ppy)(μ2-Spy)}2], 1, gave complex [Pt(ppy)(η1-S-Spy)(PPh3)], 2, as a result of platinum–nitrogen bonds dissociation. Complex 2 revealed anionic selectivity upon protonation reaction with acidic species.

The synthesis and characterization of three sixcoordinated Pt(IV) complexes with the stoichiometry [Pt(Ar) 2 (S ∧ N) 2 ] (S ∧ N = Sbt, benzothiazole-2-thiolate, Ar = p-MeC 6 H 4 (1a), C 6 F 5 (1b); S ∧ N = Spy, 2-pyridinethiolate, Ar = p-MeC 6 H 4 (1c)) is described. Of these, 1a undergoes, at room temperature and within 18 h, a remarkable C−C reductive elimination process between the aryl ligands to give, as the final products, the stable binuclear lantern complex [Pt 2 (Sbt) 4 ] (2a) and 4,4′-dimethylbiphenyl. Differently from 1a, solutions of 1b,c are indefinetively stable up to 60 °C and do not undergo reductive elimination. Complexes 1a−c and 2a were characterized by IR and NMR spectroscopy, high-resolution mass spectrometry, and singlecrystal X-ray crystallography (1b,c and 2a). 1 H− 19 F HOESY experiments on 1b demonstrated the presence of a "through-space" coupling between proximal F and H atoms of the molecule that are separated by six bonds but are in close spatial proximity.