There is a dire need for new compounds to combat antibiotic resistance: metal complexes might provide the solution. 906 metal complexes were evaluated against dangerous ESKAPE pathogens and found to have a higher hit-rate than organic molecules.

The directed synthesis of organometallic cage molecules for the assembly of molecular nano-objects is a topical area of chemical research.[1] By combining the "molecular clip" strategy developed by Stang [2] with the "molecular paneling" strategy pioneered by Fujita, [3] we recently synthesized trigonal-prismatic cage molecules in which six (h 6 -arene)ruthenium or (h 5 -pentamethylcyclopentadienyl)rhodium units are held together by two trigonal 2,4,6-tris(pyridin-4-yl)-1,3,5-triazine (tpt) panels and three dichloro [4] or oxalato [5] (Figure 1). [7] The structure shows the [Pt(acac) 2 ] complex to be held between the triazine units of the tpt ligands. It is clear from the van der Waals representation of the "complex-in-a-complex" cation that the Pt(acac) 2 complex is indeed encapsulated in 1 6+; the separation between platinum and triazine-centroid being 3.4 . The {Ru 2 - Centre is gratefully acknowledged. M = Pd, Pt; acac = acetylacetonato; tpt = 2,4,6-tris(pyridin-4-yl)-1,3,5-triazine; dhbq = 2,5-dihydroxy-1,4-benzoquinonato.

The unique properties of transition metal complexes, such as environment-responsive ligand exchange kinetics, diverse photochemical and photophysical properties, and the ability to form specific interactions with biomolecules, make them interesting platforms for selective drug delivery. This minireview will focus on recent examples of rationally designed complexes with bioactive ligands, exploring the different roles of the metal, and mechanisms of ligand release. Developments in the techniques used to study the mechanisms of action of metal-drug complexes will also be discussed, including X-ray protein crystallography, fluorescence lifetime imaging, and X-ray absorption spectroscopy.

We present a bioreductively activated cobalt(III) carrier system for the delivery of curcumin with enhanced drug stability, tumour penetration and efficacy in hypoxic tumour regions. Curcumin is a natural product with potent anticancer activity but low bioavailability and serum stability. With the aim of overcoming these limitations, we prepared a cobalt(III) prodrug of curcumin and compared the stability, cytotoxicity and cellular uptake with those of the free drug. Using a combination of fluorescence lifetime imaging and X-ray absorption spectroscopy, we demonstrated that curcumin is released from the cobalt carrier complex in tumour cells, with strong evidence to suggest that the process occurs via reduction of the cobalt centre. Furthermore, fluorescence lifetime imaging in solid tumour models showed that the cobalt complex delivered curcumin uniformly throughout the tumour model, while free curcumin only accumulated on the outer edges. For comparison, we also investigated the isoelectronic ruthenium(II) complex and found its properties and biological activity to be very different to those of the cobalt analogue. ; Fax: +61 2 9351 3329; Tel: +61 2 9351 4233 † Electronic supplementary information (ESI) available. See

Chelating neutral (N,O) and cationic (N,N) first- and second-generation ruthenium(II) arene metallodendrimers based on poly(propyleneimine) dendrimer scaffolds were obtained from dinuclear arene ruthenium precursors by reactions with salicylaldimine and iminopyridyl dendritic ligands, respectively. The N,N cationic complexes were isolated as hexafluorophosphate salts and were characterised by NMR and IR spectroscopy, and MALDI-TOF mass spectrometry. Related mononuclear complexes were obtained in a similar manner and their molecular structures have been determined by X-ray diffraction analysis. The cytotoxicities of the mono- and multinuclear complexes were established using A2780 and A2780cisR human ovarian carcinoma cancer cell lines.