Edward R. T. Tiekink

Gold derivatives for the treatment of cancer

The cytotoxicity and anti-tumour activity screening trials for both gold(I) and gold(III) are summarised. Gold(I) thiolates employed clinically in the treatment of rheumatoid arthritis display some potency against various tumours but a greater potential is found in their analogues. In particular, analogues featuring a linear P-Au-S arrangement in which the thiolate ligand is derived from a biologically active thiol display high potency. Further, targeting mitochondria with tetrahedrally coordinated gold(I) phosphine compounds with enhanced hydrophilicity is a research direction with exciting potential. Recent research has shown that gold(III) compounds featuring square-planar geometries, as found in cisplatin, may target DNA and may provide new anti-tumour agents.

Tin Chemistry: Fundamentals, Frontiers, and Applications

Tin chemistry retains a place in contemporary science as an important element owing to its wide range of applications. New and exciting research is being generated on an annual basis from all parts of the world - the study of tin and its compounds attracts considerable interest from a range of perspectives such as organic synthesis, medicine, materials chemistry, catalysis and environment. Tin Chemistry - Fundamentals, Frontiers and Applications collects, in one comprehensive volume, authoritative and concise snapshots of modern tin chemistry in a full range of applications. Over forty of the leading tin chemistry experts have contributed reviews in six themes: fundamentals in tin chemistry. Materials chemistry and structural. Chemistry of tin compounds. Medicinal and biocidal applications of tin compounds. Tin in the environment. Tin in organic synthesis. Tin in catalysis. Tin Chemistry - Fundamentals, Frontiers and Applications is an essential overview of modern perspectives on this important element for the specialist and non-specialist alike.

Antimony and bismuth compounds in oncology

The main group elements antimony and bismuth are used clinically, primarily for the treatment of Leishmaniasis (antimony) and ulcers (bismuth). Despite their medicinal efficacy, the exploration of the anti-cancer potential of antimony and bismuth compounds is not as well developed as for other metal-containing species. The results of cytotoxicity and anti-tumour screening for antimony(III), antimony(V) and bismuth(III) compounds are summarised in this review. While this is a relatively undeveloped field of research endeavour, promising anti-tumour activity has been reported, in particular for bismuth compounds.

Synthesis, characterization and in vitro antitumour activity of triphenyl- and tri-n-butyltin benzoates, phenylacetates and cinnamates

Spectroscopic, structural and antitumour properties of triphenyltin and tri-n-butyltin benzoates, phenylacetates and cinnamates are compared with those of their corresponding pentafluorophenyl analogues.

Molecular architecture and supramolecular association in the zinc-triad 1,1-dithiolates. Steric control as a design element in crystal engineering?

A survey of the fascinating structural chemistry of the zinc-triad 1,1-dithiolates is presented. A total of twelve distinct structural motifs are delineated ranging from monomeric, dimeric, tetrameric, linear polymeric, layer to 3-dimensional network architectures. Such diversity arises from the prevalent secondary bonding interactions, i.e. A⋯S, operating in the solid state. While the variation in structure suggests that the control of secondary interactions is difficult, a possible design tool for crystal engineering is identified, namely by moderating the steric profile of thiolate-bound organic substituents, at least for the systems described herein.

Dibutyltin perfluoroalkanecarboxylates: synthesis, NMR characterization and in vitro antitumour activity

Three dibutyltin perfluoroalkanecarboxylates have been synthesized, characterized by H-1-, C-13-, F-19- and Sn-117-NMR, Mossbauer, IR and mass spectroscopy. The structure of tetra-n-butylbis(trifluoroacetato)distannoxane has been elucidated by X-ray crystallography. The in vitro antitumour activity of the three compounds against seven human tumour cell lines was found to be as high as or even higher than that for reference compounds used clinically

Gold compounds in medicine: Potential anti-tumour agents

An overview of the use of gold drugs in the alleviation of the symptoms associated with the debilitating disease rheumatoid arthritis (RA) is presented. Other potential therapies based on gold compounds, such as against parasitic diseases, HIV and asthma are summarised. The development of gold compounds as novel anti-tumour agents is also described. Compounds containing gold(I), as utilised in the treatment of RA, and gold(III), show exciting potential in this regard, there being some very potent compounds targeting biological targets, such as DNA, and displaying selectivity in their cytotoxic profiles. In conclusion, very real potential exists for the development of anti-tumour agents based on gold.

Synthesis and characterization of triphenyl-, tri-n-butyl and di-n-butyltin derivatives of 4-carboxybenzo-18-crown-6 and -15-crown-5

Abstract 1H-, 13C- and 117Sn-NMR as well as 119mSn Mossbauer spectroscopy, electrospray mass spectrometry and elemental analysis of novel trioganotin and di-n-butyltin derivatives of 4-carboxybenzo-18-crown-6 and -15-crown-5 are reported. The X-ray crystal structure of aquatriphenyltin-4,7,10,13,16-pentaoxadicyclo[13.4.0]nonadeca-1,3(17),18-trienecarboxylate hydrate consists of trigonal bipyramidal tin with a C3 trigonal plane and the axial positions occupied by an oxygen atom, derived from a monodentate carboxylate ligand, and a water molecule. In the lattice, the crown ether portions of the molecules are capped on either side, via hydrogen bonding interactions, by the coordinated and uncoordinated water molecules.

Crystal structure of the dimeric bis(p-fluoro- and pentafluorophenylacetato)tetra-n-butyldistannoxanes

Abstract The crystal structures of bis(pentafluorophenylacetato)tetra-n-butyldistannoxane, [nBu2Sn(O2CCH2C6F5)]2O2 (1 and bis(p-fluoro-phenylacetato)tetra-n-butyldistannoxane, ([nBu2Sn(O2CCH2C6H4F-p)]2O2 (2) are reported. The compounds are shown to have different dimeric structures in the crystalline state despite their structural similarity. The structures each have a centrosymmetric nBu4Sn2O2 core to which are bonded two nBu2Sn moieties. The main difference between the two structures involves the mode of attachment of one of the independent carboxylate ligands. In 1, the ligand is bidentate, bridging a pair of endo- and exo-cyclic Sn atoms by using both O atoms, whereas in 2, the comparable ligand bridges the Sn atoms by using one O atom only. The second independent carboxylate ligand is coordinated exclusively to the exocyclic Sn atom in each case. The great similarity of their NMR spectra reveals that compounds 1 and 2 have identical structures in CDCl3 solution. The NMR data indicate also the existence of a dynamic process involving averaging of the carboxylate but not the diorganotin resonances, as observed previously; a process accounting for the fluxionality is proposed. A dissociation/reassociation mechanism involving an averaging equilibrium between dimeric and monomeric distannoxanes can be formally excluded.

Supramolecular association in organomercury(II) 1,1-dithiolates. Complementarity between Hg⋯S and hydrogen bonding interactions in organomercury(II) 2-amino-cyclopent-1-ene-1-carbodithioates

A survey of the supramolecular associations operating in the crystal structures of organomercury 1,1-dithiolates shows that owing to the presence of Hg⋯S interactions, dimeric, 1-, 2- and 3-dimensional architectures are generated. Introducing hydrogen-bonding functionality into the 1,1-dithiolate ligand allows for the formation of both intra- and intermolecular hydrogen bonds as well as Hg⋯S interactions, so that 2- and 3-dimensional architectures are formed that are distinct for each of the two polymorphic forms of MeHg(S2CC5H6NH2-2) and for PhHg(S2CC5H6NH2-2).