Cyclometalated Pt(II) Complexes with Picolinate Ligands: Synthesis, Optical and Biological Properties

Resumen

Luminescent complexes based on organic chromophores with late transition metals,particularly Pt(II), have attracted a great interest in recent years due to their interesting chemicaland photophysical properties.1 Furthermore, some luminescent compounds have shownanticancer activity, which make them very interesting as organelle-targeting imaging reagents orphotosensitizers2 for diagnostic and therapeutic applications.In this work we present the synthesis, structural and optoelectronic properties of a newfamily of cyclometalated Pt(II) compounds bearing 2-(4-dimethylaminephenyl)benzothiazole oftype [Pt(Me2N-pbt)(N^O)] (N^O = 2-picolinic acid 1; 3-amine-2-picolinic acid 2; 3-hydroxi-2-picolonic acid 3; 2,4-pyridindicarboxylic acid 4). All complexes have been fully characterized andthe trans-N,N configuration was confirmed by X-Ray diffraction in 1 and 3. Their emissiveproperties have been examined in different media (solid state, solution, and polystyrene film)and supported by theoretical calculations. These complexes demonstrated potent antitumoractivity in dark conditions, in the nanomolar range, against two human tumour cell lines (MDAMN-231 and A549). Furthermore, upon a short time photoinduction (5 min) complex 3 exhibitedthe highest photoactivity index in both cell lines likely due to additional generation of 1O2.