Heavy Metal Complexes of 1, 2, 3-Triazole derivative: Synthesis, Characterization, and Cytotoxicity Appraisal Against Breast Cancer Cell Lines (MDA-MB-231)

: New chelating ligand derived from triazole and its complexes with metal ions Rhodium, Platinum and Gold were synthesized. Through a copper (I)-catalyzed click reaction, the ligand produced 1,3-dipolar cycloaddition between 2,6-bis((prop-2-yn-1-yloxy) methyl) pyridine and 1-azidododecane. All structures of these new compounds were rigorously characterized in the solid state using spectroscopic techniques like: 1 HNMR, 13 CNMR, Uv-Vis, FTIR, metal and elemental analyses, magnetic susceptibility and conductivity measurements at room temperature, it was found that the ligand acts as a penta and tetradentate chelate through N 3 O 2 , N 2 O 2 , and the geometry of the new complexes are identified as octahedral for (Rh & Pt) complexes and for (Au) complex square planner. The newly prepared compounds were designed and efficiently synthesized to be used to investigation of their toxicity bioassay (in vitro) as anticancer agent towards MDA cell lines. From the results obtained from cytotoxic assay, it can be concluded that the synthesized compounds are promising as new anticancer candidates in future especially in high concentration.


Introduction:
According to the World Health Organization's most current data, carcinoma is the world's second leading cause of death. More than 9.6 million deaths occur each year, accounting for roughly a quarter of all mortality. Several anticancer medications have been significantly improved in recent years. Nonetheless, the majority of currently available anti-cancer medications are ineffective, and side effects such as drug-induced impedance may arise. As a result, identifying and improving innovative, safe, and effective long-term cancer treatments with fewer side effects is crucial 1 . The 1,2,3-triazole and 1,2,4-triazole groups are two types of triazole are the basic units of many therapeutic medications, and their analogies have sparked the curiosity of medicinal chemists for a long time 2 . Triazole-containing heterocycles are lead molecule architectures that have attracted researchers' interest due to their broad range of biological effects, including anticancer 3 , characteristics that are antimicrobial, antitubercular, anti-HIV, anti-convulsant, antibacterial, anti-inflammatory, analgesic, and antiviral 2 . Click chemistry reactions is important in medicinal chemistry and chemical biology cannot be overstated 4 . It is a potent and adaptable technology that can be used to design new anticancer drugs based on platinum and a better understanding of their biological actions at the level of the cell. To increase tumor targeting, new azidealkyne cycloaddition techniques are being employed to functionalize Pt-based complexes with bio molecules 5 . Click-based detection, separation, and tracking of Platinum drug surrogates in biological and cellular settings also gives crucial information about Pt-based pharmacological modes of action and resistance 6 . Inorganic Pt-click reactions, however less well-studied, allow the production of novel (potentially multimetallic) Pt complexes as well as realistic methods for adding functional groups and monitoring Pt-azido drug localization 7 . The target of this study is to look into the anticancer properties of Rhodium, Platinum, and Gold complexes that contained a chelating 1, 2, 3-triazole derivative.

Materials:
Whole of both the solvents and the chemicals used in the process of synthesis of new compounds were achieved from Sigma-Aldrich and Merck. The Agilent spectrometer (FT-IR 8400S SHIMADZU Spectrophotometer) was used to measure FTIRspectra of prepared complexes and their ligand in the solid-state at the range of wavenumber at 4000-400 & 4000-200 cm -1 using KBr & CsI pellets. The measurement of electronic spectra of all prepared compounds was obtained in liquid state by the instrument (UV-1800 PC) Shimadzu spectrophotometer at λrange = 190-1100 nm using quartz cell of 1 cm. Bruker DPX spectrometers operating at 600 MHz were used to obtain NMR spectra. Mass spectra were recorded on DIRECT PROBE. The Euro EA3000 analyzer was used for the determined (C, H, and N) contents. Melting points were examined in open glass capillaries. The electrical conductivity meter (WTW), and magnetic susceptibility of complexes at 25°C were determined. Thin layer chromatography was employed to adjust the reaction and the silica plates were used (60 F254, 0.2 mm), which carried alkaline potassium permanganate dip.

Scheme 1. Shows the sequential steps to prepare the ligand [DTMML]. Metal-Complexation:
The current work includes using (1mmol) of the metal salts [RhCl3 (0.209g), H2PtCl6 (0.486g), and HAuCl4.H2O (0.411g)] in an ethanoic solution undergoes the reaction and (0.637g, 1mmol) the ligand is added to an ethanoic solution of mineral salts while stirring (10 ml) in a (1:1) molar ratio. The mixture of reaction was refluxed for a few hours (2-3 hours) under heating 10 . Colorful precipitates were formed during this period, they were filtered several times and washed with ether then left to dry in a desiccator. As indicated in Table. 1, Spectroscopic, analytical and physical techniques were used to characterize all the complexes generated.

Cytotoxic assay
The effect of cytotoxicity of complexes with their ligand were determined using the colometric 3-(4,5-dimethyl thiazole-2-yl)-2,5-biphenyl. The MDA-231 cell lines used in this work were obtained from Al-Nahrain University's biotechnology center. Results and Discussion: The resulting complexes and its chelated were colored powders that remained stable in the open atmosphere for a long period. Table 1 lists the physio-chemical properties of resulting compounds. The results of the metal analysis agree with the calculated values in a satisfactory manner. Measurements of spectral and magnetic moments backed up the proposed molecular formula.

Infrared spectroscopic study
A study of Infrared spectroscopy with CsI disc was used to record all of the spectra in the solid state.

Electronic spectra, Magnetic susceptibility and Conductivity measurements:
Additional structural tools were used to confirm the geometry of the produced complexes, from the data of electronic spectra, magnetic moment, and electrical measurements for their solution in DMSO. The complexes' uv-vis spectra were obtained in the region (190-1100) nm.

A-Spectra of the [DTMML]
: Figure. Table. 3.  Table. 3. Figure. 9 shows the electronic spectrum of a produced yellowish-orange complex of platinum (IV) ion, which showed two absorption bands at belonged to the transitions referring to t conductance behavior indicates an electrolyte of this complex. In addition, the analysis of data and spectroscopy techniques, and these result, proved that the octahedral geometry was suggested for this complex. As shown in scheme. 2, and Table. 3. Figure.     The mass spectrum of (L) shown in Fig. 13, was observed by the peak of molecular ion at m\z =637 which confirmed the molecular weight m\z value of 637g\mol -1 that compatible with the experimental ligand formula (C37H63N7O2) 27

Cytotoxic assay:
Breast cancer is the popular type of tumors for women in the worldwide, which represents approximately twenty-five percent of all female malignant tumors which has extend widely in most . Furthermore, 28 s countries, even developed countrie despite the fact that many additional medications have been launched to the market, the response to therapy remains low. As a result, there is a pressing need to produce more effective anticancer focus on . Most research groups are 29 medications developing a practical anticancer medicine that can be utilized effectively to treat human cancers. This study gives? indication that the synthetic ligand and  Table 4, Least Significant Difference (LSD Value) is recorded in this table also. MTT assay was applied to assess cytotoxicity and viability of the MDA-MB-231 cell lines after 24 hours of treating by different concentrations (12.5; 25; 50; 100; 200 and 400) μg/ml of newly prepared compounds (Table. 4 and Fig. 14). MTT assay results showed a high inhibition rates for free ligands and their metal complexes as comparison with negative control cells which left without treatment. All metal complexes showed high toxicity relative to ligand and recorded high inhibition rate i.e. (85, 85 & 84 %) especially at high concentrations 400μg/ml for each of L-Rh, L-Pt and L-Au sequentially and the inhibition rates began to reduce gradually from high to low concentrations. Pharmacological effects of these complexes can be returned to variety circumstances, such as, synthetic derivatives in a similar manner to natural material follow apoptosis and autophagic pathways to inhibit the growth and activity of breast cancer cells. Other than that inhibition of cell proliferation, induction of cell-. As well as presence of 30 rrest may occur cycle a 1,2,3-Triazole could be readily interact with diverse enzymes. Our current work highlights in 1,2,3triazole-containing compounds with anti-breast cancer potential, and their structure-activity relationship (SAR) together with of action to pave the way for the further rational development of novel anti-breast cancer mechanisms candidates. On the other hand, Pyridines are potential inhibitors and some pyridine-based agents, have already been applied in clinical practice or under clinical trials for -. Thus, gathering of 1,2,3 31 the treatment of cancers triazole with pyridine may give chances to develop new anticancer agents. An antiproliferative SAR of 1,2,3-triazole-containing pyridine derivatives indicates that these groups are against cell lines . The most active compounds 32 favorable for the exhibit higher activity than the others concentrations reveal that these compounds in high concentration could inhibit the microtubule assembly, arrest the 2/M phase, and induce cell death cell cycle at the G . 31 by apoptosis

Conclusion:
According to the findings, new derivative of triazole [DTMML] and spectroscopic tests, analysis of elements (AA & CHNS), magnetic dipole moment, and complexes conductivity at room temperature were used to validate the structure of its complexes. In the solid state, we propose that Rh(III) and Pt(IV) complexes have six coordination numbers with octahedral geometries, whereas the Au(III) complex has four coordination numbers with square planer shape. The anticancer MDA cell line was used to test these substances, and it was discovered that the higher the concentration, the more efficient they are against cancer cells. For these complexes, the