A range of ruthenium-arene compounds with chloride, bromide or iodide ligands were prepared and tested as catalysts for the homogeneous redox neutral alkylation of tert-butylamine with phenethyl alcohol, and compared to the previously reported catalyst [RuCl₂(p-cymene)]₂, in the presence of the diphosphine 1,1′-bis(diphenylphosphino)ferrocene (dppf). The best catalytic activities were obtained with ruthenium iodide compounds. The formation of either [RuX(p-cymene)(dppf)][X] or [(RuX₂(p-cymene))₂(dppf)] (X = halide) under the catalytic conditions employed was investigated.

Group IV metal complexes have previously shown promise as novel anticancer agents. Here, we discuss the mechanistic and cytotoxic nature of a series of group IV β-diketonate coordination complexes. Clear evidence that the ligands are exchangeable on the metal centre and that the β-diketonate ligands can act as potential drug delivery vehicles of the group IV metal ions was obtained. When evaluated for the cytotoxicity against human colon adenocarcinoma (HT-29) and human breast adenocarcinoma (MCF-7) cell lines, a general trend of decreasing potency down the group IV metals was observed. The most promising results obtained were for the hafnium complexes, with the tris diphenyl β-diketonate hafnium complex exhibiting IC₅₀ values of 4.9±0.9 μM and 3.2±0.3 μM against HT-29 and MCF-7, respectively, which are comparable with the activity of cisplatin against the same cell lines. This tri β-diketonate hafnium complex is the first to show potent in vitro cytotoxic activity. The results reported show that ligand design has a significant effect on the cytotoxic potential of the complexes, and that these group IV complexes warrant further evaluation as novel metal-containing anticancer agents.

The use of picolinic acid amide derivatives as an effective family of bidentate ligands for copper-catalysed aryl ether synthesis is reported. A fluorine-substituted ligand gave good results in the synthesis of a wide range of aryl ethers. Even bulky phenols, known to be very challenging substrates, were shown to react with aryl iodides with excellent yields using these ligands. At the end of the reaction, the first examples of end-of-life Cu species were isolated and identified as Cu^II complexes with several of the anionic ligands tested. A preliminary mechanistic investigation is reported that suggests that the substituents on the ligands might have a crucial role in determining the redox properties of the metal centre and, consequently, its efficacy in the coupling process. An understanding of these effects is important for the development of new efficient and tunable ligands for copper-based chemistry.