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

Abstract

The optical and biological properties of 2-(4-dimethylaminophenyl)benzothiazole cycloplatinated complexes fea-Complexes 1-6 display 1 ILCT and metal-perturbed 3 ILCT dual emissions. The ratio between both bands is excitation dependent, accomplishing warmwhite 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.

Luminescent Anionic Cyclometalated Organoplatinum (II) Complexes with Terminal and Bridging Cyanide Ligand: Structural and Photophysical Properties

“…In the binuclear complexes ( 7 – 9 ), the lowest-energy absorptions appear subtle red-shifted and exhibit a higher extinction coefficient compared with the mononuclear analogues ( Figure 5 c), a fact attributed to the incorporation of two chromophores which are involved electronically. 72 In the binuclear complexes 7 and 8 , the LE absorption has mainly 1 LC/ 1 MLCT admixture with 1 L″LCT [π(CN − ) → π*(C^N)] contribution, whereas in the case of 9 has mixed 1 LC/ 1 MLCT/ 1 L′LCT [π( p- MeC 6 H 4 ) → π*(C^N)] configuration. The calculations suggest that the bimetallic Pt–CN–Pt unit enables an increase of the 1 MLCT contribution in the LE band along with a decrease of the 1 LC contribution in relation to the monomers.…”

A new family of luminescent iridium complexes: synthesis, optical, and cytotoxic studies

“…The longer the t R , the more lipophilic the character of the complex. 62,88 In case of these Ir( iii ) complexes, the presence of substituents on the cyclometalated groups remarkably decreased the t R (H > CHO > COOH) (Table S9†), with 2a-Cl ( t R = 3.28) and 3a-PF 6 ( t R = 1.99) being the most lipophilic ones. The higher lipophilicity of 2a-Cl is in accordance with the good cytotoxicity activity found for this complex, which displays the lowest IC 50 values (Table 3).…”

“…As a rule, all the complexes were more active towards the A549 cell line rather than HeLa, in accordance with our previous results. 62,66…”

“…DPBF reacts with ROS to generate 1,2-dibenzoylbenzene, resulting in an absorbance decline at 410 nm. 62,63 The activity of a mixture of each complex with DPBF in acetonitrile solution, employing [Ru(bpy) 3 ] 2 as a reference (φ S Δ = 0.56), 64 was measured under blue light irradiation (λ 460 nm). A clear decrease in the absorbance of the DPBF band at 410 nm (Fig.…”

“…As a rule, all the complexes were more active towards the A549 cell line rather than HeLa, in accordance with our previous results. 62,66 In order to evaluate the selectivity index (SI) of complexes towards the tumour cell lines, we used normal epithelial lung virus-transformed BEAS-2B cells as a non-tumor reference cell line. Cisplatin IC 50 value towards this cell line was 1.74 μM, slightly lower than those for A549 and HeLa cells, therefore rendering low SI values of this anti-cancer drug for these cell lines (0.27 and 0.13, respectively) (Table 3).…”