Investigation on Optical and Biological Properties of 2‐(4‐Dimethylaminophenyl)benzothiazole Based Cycloplatinated Complexes

The optical and biological properties of 2‐(4‐dimethylaminophenyl)benzothiazole cycloplatinated complexes featuring bioactive ligands ([{Pt(Me(2)N‐pbt)(C(6)F(5))}L] [L=Me(2)N‐pbtH 1, p‐dpbH (4‐(diphenylphosphino)benzoic acid) 2, o‐dpbH (2‐(diphenylphosphino)benzoic acid) 3), [Pt(Me(2)N‐pbt)(o‐dpb)] 4, [{Pt(Me(2)N‐pbt)(C(6)F(5))}(2)(μ‐PR( n )P)] [PR(4)P=O(CH(2)CH(2)OC(O)C(6)H(4)PPh(2))(2) 5, PR(12)P=O{(CH(2)CH(2)O)(3)C(O)C(6)H(4)PPh(2)}(2) 6] are presented. Complexes 1–6 display (1)ILCT and metal‐perturbed (3)ILCT dual emissions. The ratio between both bands is excitation dependent, accomplishing warm‐white emissions for 2, 5 and 6. The phosphorescent emission is lost in aerated solutions owing to photoinduced electron transfer to (3)O(2) and the formation of (1)O(2), as confirmed in complexes 2 and 4. They also exhibit photoinduced phosphorescence enhancement in non‐degassed DMSO due to local oxidation of DMSO by sensitized (1)O(2), which causes a local degassing. Me(2)N‐pbtH and the complexes specifically accumulate in the Golgi apparatus, although only 2, 3 and 6 were active against A549 and HeLa cancer cell lines, 6 being highly selective in respect to nontumoral cells. The potential photodynamic property of these complexes was demonstrated with complex 4.