Cytotoxic Effect of Samarium(III)-Based Complexes: Synthesis, Characterization and Photoluminescence Properties

Three new homoleptic six-coordinate Sm(III) complexes have been synthesized from diketone ligand with different substituent groups. The structural properties of these compounds have been investigated using elemental analysis, UV-Vis, and FT-IR approaches. Then, their photoluminescence properties of the synthesized Sm complexes have been examined. Also, the cytotoxic activities of the complexes have been studied against to human epidermoid carcinoma cell (HTB-54) and normal bronchus epithelial cell (BEAS-2B). According to result, the [Sm(MPBP- 1,3 PPon) 3 ]·H 2 O) (IC 50 : 11.05 μM) complex was more active than [Sm(BMP- 1,3 PPon) 3 ]·2H 2 O (IC 50 :58.64 μM) and [Sm(BCP- 1,3 PPon) 3 ]·H 2 O (IC 50 : >500 μM) complexes. Otherwise it was no effect on normal cell (BEAS-2B). This result shows that complex [Sm(MPBP- 1,3 PPon) 3 ]·H 2 O) has the potential to be the ideal chemotherapeutic drug.


Introduction
The luminescence characteristics of rare earth metal complexes with various organic ligands have recently received a lot of attention. There are many studies in the literature on the synthesis and photophysical characteristics of lanthanide complexes with different substituents of β-diketone ligands. [1].
The lanthanide ions are one of the essential components because of their spectroscopic and magnetic properties in the preparation of new materials and as suitable probes in studies of biological systems. [34].
Lung cancer is described as the deadliest type of cancer that causes 1.76 million deaths out of 2.09 million cases in the World [35]. There are two commonly known groups of lung cancers: small cell and non-small cell lung cancer. Epidermoid cancer, also called squamous cancer, is a type of non-small cell lung cancer [36]. Non-small cell lung cancer (NSCLC) is the most common group of lung cancer, occurring in eight or nine out of ten cases. Despite the use of chemotherapy, radiotherapy and immunotherapy, the 5-year survival rate is 15% when all cases are included. Unfortunately, the chemotherapy drugs such as cisplatin-based cause side effects on renal [37], liver [38] cells after treatment. For years, especially pharmacology and chemist researchers have been synthesized hundreds of new potential anti-cancer compounds to reduce the toxic effect.

UV-Vis specta
The UV-Vis spectra of Sm(III) complexes were obtained in the range of 190-1100 nm by using DMF, DMSO and DCM solvents and the corresponding spectra are presented in Figure 4-6. These bands found in the UV-Vis spectra of Sm(III) complexes at 360, 365, and 358 nm in the DMF solution are linked to the singlet-singlet n-π* transition of enol groups. Furthermore, the π-π* transition of phenyl rings and carbonyl groups is ascribed to the absorption maxima at 268 nm. In DMSO, DMF, and DCM, the absorption wavelength of Sm(III) complexes was found to be slightly red shifted depending on the polarity of the solvent. [45][46][47][48].

Supplementary Files
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