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We report the synthesis and characterisation of new, highly fluorescent, zinc complexes of bis(thiosemicarbazone) ligands incorporating extended aromatic backbones which are cytotoxic at levels comparable to cisplatin; cellular fluorescence imaging studies suggest these cause cell death by disruption of mitochondria. [ABSTRACT FROM AUTHOR]

2-Formylpyrrole and 2-acetylpyrrole were deprotonated with NaH to give the corresponding Na salts 1a and 1b, respectively. The reactivity of these salts towards cobalt chloride compounds was studied. The resulting new bis(ketopyrrolyl) Co(ii) 19-electron complexes [Co(κ2N,O-2-NC4H3C(R)=O)2(PMe3)2] (R = H 2a, and Me 2b) were characterised by single crystal X-ray diffraction, to show an octahedral geometry with the PMe3 ligands in trans positions to each other, and two bidentate ketopyrrolyl ligands occupying the remaining coordination positions in a transoid conformation. Powder and solution magnetic susceptibility measurements together with EPR and UV/Vis/NIR spectra revealed a low-spin ground state (dz2, S = 1/2) for Co(ii) in these compounds. Analysis of the EPR superhyperfine couplings suggested that the longer distances (z axis) of the hexacoordinate Co coordination sphere are occupied by the keto-O atoms of the bidentate ligand, leaving the pyrrolyl N and the phosphine P atoms within the equatorial plane. This is confirmed by means of DFT calculations, which also indicate that the most thermodynamically stable isomers are low-spin (S = 1/2) complexes with coordination geometries corresponding to the molecular structures obtained by X-ray crystallography. [ABSTRACT FROM AUTHOR]

New M(ii) bis(thiosemicarbazonato) complexes (M = Ni(ii), Cu(ii) and Zn(ii)) featuring allyl groups at the exocyclic nitrogens have been synthesised. The complexes were characterised in solution by spectroscopic methods and their solid state structures determined by single crystal X-ray diffraction using synchrotron radiation. The Zn(ii) complex was found to be intrinsically fluorescent and soluble in biocompatible media. The uptake of this Zn(ii) complex in HeLa, MCF-7 and IGROV cancer cells was monitored by fluorescence microscopies (epi- and confocal fluorescence imaging). The radiolabelling to 64Cu(ii) bis(thiosemicarbazonato) complex was performed cleanly by transmetallation from the corresponding Zn(ii) species using 64Cu(OAc)2. [ABSTRACT FROM AUTHOR]

Kinetic stability studies of a series of pseudorotaxanes formed from electron-rich crown ethers (hosts 1 and 2) and naphthalene diimide (guest A) in the presence of alkali salt templates MX (where M+ = Li+ and Na+, and X− = Cl−, Br−, I−, NO3− and CF3SO3−) were performed by 1H NMR. The switching between the (bound) host 1 and its linkage isomer host 2 (free) was monitored in solution in the presence and absence of alkali salts, to establish the relative thermodynamic stabilities in the series. We also report here six new crystal structures, for pseudorotaxanes of type: [1·A], [M2·1·A]2+ and [M2·2·A]2+. Their solution-phase structures are in good agreement with the solid-state structures determined by X-ray crystallography. [ABSTRACT FROM AUTHOR]