Substituent‐Dependent Absorption Spectra, Electrochemical and Antiproliferative Activity Studies of Some 3‐(4‐(Benzyloxy)phenyl)‐5‐(4‐methoxyphenyl)‐1‐(substitutedphenyl)formazans

Abstract

We have reported the effect of electron donating and withdrawing substituents on absorption and electrochemical properties of formazan derivatives as well as antiproliferative activity. New formazans F2 and F4 bearing electron donating subunits have been synthesized, and characterized via elemental analysis and various spectroscopic techniques. The substituent effects and solvatochromic of formazan derivatives F2-F5 having different substituents on 1-phenyl ring in eleven solvents were investigated by absorption spectroscopy. Whilst their absorption bands are only slightly dependent on the polarities of solvents, the considerable alteration was detected by modifying the electronic characteristic and positions of the substituents. Then, the antiproliferative activity of all compounds was investigated in four cancer cell lines using MTT and XTT assay methods. The IC 50 values of F2 and F4, having electron donating methoxy and methyl subunits were obtained in the ranges of 10.60 and 21.53 μM in DLD-1 and HepG2 cell lines. Our study demonstrates that F2 and F4 are more active than the positive control drug used.

Synthesis, Optical and Electrochemical Properties of Novel Formazan Analogs Incorporated Fluorene Moiety

“…For example, the FT‐IR spectral data of newly synthesized formazan derivatives 4 a – e revealed the presence of N−H weak bands in the 3348–3359 cm −1 and 3196–3239 cm −1 region. The presence of these types of weak bonds exhibits the existence of intramolecular hydrogen bonding [30–36] . In addition, the presence of sharp bands in the 1595–1622 cm −1 region, confirm the presence of the C=N groups as the reported FT‐IR values [30–36] .…”

“…Subsequently, in a second step, the radical Fz⋅ releases another electron, resulting in a tetrazolium cation (TFz + ). Thus, the reaction scheme generally has been depicted as follows: [30–36,40] $$$\vcenter{\openup.5em\halign{$\displaystyle{#}$\cr {\rm FzH} \to {\rm FzH}{^{+}}{^{\bullet}}+{\rm e}{^{- }}\ ({\rm electrode}\ {\rm reaction})\hfill\cr}}$$$ $$$\vcenter{\openup.5em\halign{$\displaystyle{#}$\cr {\rm FzH}{^{+}}{^{\bullet}} \to {\rm H}{^{+}}+{\rm Fz}{^{\bullet}}\ ({\rm chemical}\ {\rm reaction})\hfill\cr}}$$$ $$$\vcenter{\openup.5em\halign{$\displaystyle{#}$\cr {\rm Fz}{^{\bullet}} \to {\rm TFz}{^{+}}+{\rm e}{^{- }}\hfill\cr}}$$$ …”

“…Subsequently, in a second step, the radical Fz * releases another electron, resulting in a tetrazolium cation (TFz + ). Thus, the reaction scheme generally has been depicted as follows: [30][31][32][33][34][35][36]40] FzH…”

“…The latter chemical shift values strongly confirm the existence of the intramolecular hydrogen bond in conjugated backbone of the formazan molecule. [33][34][35][36][37][38][39] Expectedly, the value of δ for the aromatic protons are resonating between 6.77-8.10 ppm for all compounds 4 a-e. In case of a formazan derivative 4 a that have a methoxy group, the protons of the methoxy substituent (À OCH 3 ) is obtained as singlet signal at 3.77 ppm.…”

“…It has been noted that these bands are generally similar in appearance to those peaks appeared with the À N=NÀ fragment. [30][31][32][33][34][35][36] As shown in Table S2, analysis of absorption properties will be focused on the λ max1 values which is more significant to the formazan structure.…”