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.

Aromatase inhibitors (AIs) as effective candidates have been used in the treatment of hormone-dependent breast cancer. In this study, we have proposed 300 structures as potential AIs and filtered them by Lipinski's rule of five using DrugLito software. Subsequently, they were subjected to docking simulation studies to select the top 20 compounds based on their Gibbs free energy changes and also to perform more studies on the protein-ligand interaction fingerprint by AuposSOM software. In this stage, anastrozole and letrozole were used as positive control to compare their interaction fingerprint patterns with our proposed structures. Finally, based on the binding energy values, one active structure (ligand 15) was selected for molecular dynamic simulation in order to get information for the binding mode of these ligands within the enzyme cavity. The triazole of ligand 15 pointed to HEM group in aromatase active site and coordinated to Fe of HEM through its N4 atom. In addition, two π-cation interactions was also observed, one interaction between triazole and porphyrin of HEM group, and the other was 4-chloro phenyl moiety of this ligand with Arg115 residue.

Mononuclear complexes [Pt­(ppy)­(S∧S)] (1a, S∧S = O,O′-di­(cyclohexyl)­dithiophos­phate (ctp); 2a, S∧S = O,O′-di­(butyl)­dithiophos­phate (btp)) and [Pt­(bzq)­(S∧S)] (1b, S∧S = ctp; 2b, S∧S = btp) have been prepared by the reaction of precursor complexes [Pt­(C∧N)­Cl­(dmso)], C∧N = deprotonated form of 2-phenylpyrdine (ppy) and 7,8-benzoquinoline (bzq), and potassium salt of S∧S ligands. All complexes were characterized by NMR spectroscopy, and the structure of 2b was further identified by single crystal X-ray determination. Although the complexes are not luminescent in solution at ambient temperature, they become strong emissive materials (bright green) in solid state (at room temperature) with high quantum yields and long lifetimes in the microsecond domain. In frozen glass state or at low temperature (solid state), these complexes become better emissive in relation to room temperature. UV–vis spectra, supported by TD-DFT calculations, indicate that 1ILCT (intraligand charge transfer) predominates over the other transitions (L = C∧N cyclometalated ligand). Accordingly, 1 and 2 exhibit structured emission bands which display a large involvement of 3LCCT (ligand-centered charge transfer) with lower contribution of 3MLCT (metal to ligand charge transfer) transition in the excited states. Also, biological activities of 1 and 2 were evaluated against three human cancer cell lines including A549 (human lung cancer), SKOV3 (human ovarian cancer), and MCF-7 (human breast cancer). 2a presented an effective potent cytotoxic activity regarding to the cell lines. The cellular localization of 1a and 2a in MCF-7 human cells was investigated by fluorescence microscopy.

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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.

Twelve novel quinazolinone–pyrimidine hybrids were synthesized, of which some of them showed dual functions as DPP-4 inhibitors and anti-cancer agents.

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