Platinum-based compounds are actively used in clinical trials as anticancer agents. In this study, two novel platinum complexes, (C1 = [PtCl2(N(SO2quin)dpa)], C2 = [PtCl2(N(SO2azobenz)dpa)]) containing quinoline and azobenzene appended dipicolylamine sulfonamide ligands were synthesized in good yield. The singlet attributable to methylene CH2 protons of the ligands of C1 and C2 appears as two doublets in 1H NMR spectra, which confirms the presence of magnetically nonequivalent protons upon coordination to platinum. Structural data of N(SO2quin)dpa (L1), N(SO2azobenz)dpa (L2) and PtCl2(N(SO2quin)dpa) confirmed the formation of the desired compounds. Time-dependent density functional theory calculations suggested that the excitation of L1 show quin-unit-based π⟶π
∗
excitations (i.e., ligand-centered charge transfer, LC), while C1 shows the metal-ligand-to-ligand charge-transfer (MLLCT) character. L1 displays intense fluorescence from the 1LC excited state, while C1 gives phosphorescence from the 3LC state. Mammalian cell toxicity of ligands and complexes was assessed with NCI–H292 nonsmall-cell lung cancer cells. Further, C1 and C2 showed significantly low IC50 values compared with N(SO2azobenz)dpa and PtCl2(N(SO2quin)dpa). Fluorescence imaging data of both ligands and complexes revealed the potential fluorescence activity of these compounds for biological imaging. All four compounds are promising novel candidates that can be further investigated on their usage as potential anticancer agents and cancer cell imaging agents.
Three new Pt complexes, [PtCl2(N(SO2(2-nap))dpa)], [PtCl2(N(SO2(1-nap))dpa)] and [PtCl2(N(SO2pip)dpa)], containing a rare 8-membered ring were synthesized in good yield and high purity by utilizing ligands which contain a dipicolylamine moiety.
Neutral and cationic rhenium complexes provide both hydrophilic as well as hydrophobic properties due to the robustness of the tridentate ligand system of biphenyl appended dipicolylamine (N(SO2bip)dpa) and diethylenetriamine (N(SO2bip)dienH) coordinated to the [Re(CO)3]+ core, hold immense potential for the development of metal based anticancer drugs. This was achieved by the synthesis of two ligands (L1: N(SO2bip)dpa and L2: (N(SO2bip)dienH) and their corresponding Re complexes (C1: [Re(CO)3(N(SO2bip)dpa)]PF6 and C2: [Re(CO)3(N(SO2bip)dien)] in good yield and high purity. All four compounds were characterized by 1H NMR, UV-Vis, FTIR spectroscopies and L1, also by single crystal X-ray diffraction. The methylene protons observed as a singlet at (4.59 ppm) in a 1H NMR spectrum of L1 appear as two doublets (5.66 and 4.65 ppm) in the spectrum of C1. The appearance of NH signals at 3.48, 5.17 and 6.69 ppm in the 1H NMR spectrum of C2 confirm the coordination of L2 with Re. The stretching vibration frequencies depicted by the S-N bond at 923 cm-1 for L1 appear towards lower frequencies (821 cm-1) in an FTIR spectrum of C1, while the S-N bond at 943 cm-1 for L2 appears towards higher frequencies (968 cm-1) in C2. In silico assessment of drug likeliness revealed zero violations demonstrating a high likeliness of the ligands to be successful as drug leads. All four compounds have shown very low IC50 values against non-small cell lung cancer cells (NCI-H292). Therefore, L1, C1, L2 and C2 are promising novel compounds that can be further investigated as potential anticancer agents.
Keywords: Rhenium Tricarbonyl, Sulfonamide, Anticancer, Fluorescence.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.