Synthesis, radiolabelling and confocal fluorescence microscopy of styrene-derivatised bis(thiosemicarbazonato)zinc and -copper complexes
Holland JP., Barnard PJ., Bayly SR., Betts HM., Churchill GC., Dilworth JR., Edge R., Green JC., Hueting R.
The synthesis of zinc(II) and copper(II) complexes of an unsymmetrical bis(thiosemicarbazonato) ligand containing a reactive styrene group are reported. The compounds have been characterised by a range of techniques including reverse-phase HPLC, cyclic voltammetry, NMR, UV/Vis, electron paramagnetic resonance and fluorescence emission spectroscopy. Time-dependent density functional theory calculations have been used to assign the electronic absorption spectrum of [Zn II ATSM] and probe the nature of the fluorescent excited state. Electrochemistry experiments show that the copper(II) complex undergoes quasi-reversible one-electron reduction at biologically accessible potentials and is within the range proposed for the complex to be hypoxiaselective. The copper-64 radiolabelled complex has been prepared in aqueous solution and characterised by reversephase radio-HPLC. Cellular uptake in HeLa cells has been observed using confocal fluorescence microscopy. © Wiley-VCH Verlag GmbH & Co. KGaA, 2008.