Acenaphthene-imidazole based chemosensors for selective detection of tin and copper ions and their biological application Rajendran Praveena, Chidhambaram Sathya, Nallathambi Sengottuvelan, Franc Perdih, Ayyanar Siva New Journal of Chemistry, 2026 Two chemosensors derived from acenaphthene-imidazole hybrid were synthesized and characterised for the purpose of detecting tin (Sn 2+ ) and copper (Cu 2+ ) ions detection limits were calculated to be 1.2 × 10 −9 M and 2.1 × 10 −9 M, respectively.
Acetylacetonate Derived Cobalt(III) Complexes as Photocatalysts and Electrocatalysts for Energy Conversion Thamilarasan Vijayan, Abida Batool, Yu Mi Park, Jinheung Kim, Rodrigo Arancibia, Nallathambi Sengottuvelan Chempluschem, 2025 Developing systems that facilitate the conversion of solar energy into fuel by reducing carbon dioxide and producing hydrogen could bridge the gap between production and consumption. In this work, a new method to study the reaction intermediates of carbon dioxide reduction reaction (CO2RR) and hydrogen elimination reaction (HER) catalyzed by Cobalt(III) catalysts with high photocatalytic activity in a water/acetonitrile solvent system is proposed. The optimization of the cobalt catalysts ([Co(acac)(bpy)(N3)2].H2O 1, [Co(acac)(en)(N3)2] 2 and [Co(acac)(2‐pic)(N3)2] 3) for photocatalytic activities in visible light irradiation (>420 nm) is performed by varying solvents systems (v/v) (CH3COCH3/H2O, CH3CN/H2O, DMF/H2O, EtOH/H2O and H2O), sacrificial electron donors (1‐benzyl‐1,4‐dihydronicotinamide (BNAH), diethanolamine (DEOA), triethylamine (TEA), and triethanolamine (TEOA), photosensitizers (Eosin Y, Erythrosin B, Fluorescein (Fl), Rose Bengal, Rhodamine‐B, and Ru(bpy)3 (Ru)), pH (7–12.5) and different catalyst concentrations (0–2 mM). The arrangement around the Cobalt(III) ion is an octahedral coordination geometry. A combination of experimental characterization and density functional theory (DFT) is used to identify the mechanism of the photocatalytic CO2 reduction reaction. DFT calculations and experimental results for the photocatalytic activity of the catalysts 1–3 reveal the involvement of multi‐electron metal‐ligand exchange coupling in promoting CO2RR and HER, and provide a starting point for the integration of these strategies into catalyst design.
Photo-, Electro-, Catalysts Based on Schiff Base NiII Complexes for Formate/Hydrogen Generation and Their Potential Biomedical Applications Thamilarasan Vijayan, Abida Batool, Yu Mi Park, Jinheung Kim, Nallathambi Sengottuvelan Applied Organometallic Chemistry, 2025 Transition metal complexes, particularly those derived from Schiff bases, are of considerable interest due to their multifunctional biological and photocatalytic properties, especially in formate production and hydrogen evolution. In this study, two nickel(II) complexes, [Ni(L 1 )(pyS)] ( 1 ) and [Ni(L 1 )(MBT)] ( 2 ), were synthesized and systematically evaluated for their photocatalytic and biological performances. Various organic dyes were employed as photosensitizers, while amines or bases served as sacrificial electron donors for visible‐light‐driven (> 420 nm) CO 2 reduction and hydrogen generation. The photocatalytic conditions were optimized by varying the pH (7–12.5), solvent ratios, and catalyst concentrations (2 mM). Density functional theory (DFT) studies revealed that complex 2 has a lower activation energy barrier (0.025 eV) for CO 2 ‐to‐formate conversion than complex 1 (0.043 eV). Both Ni(II) complexes demonstrated strong interactions in DNA/BSA binding studies, notable cytotoxicity toward HCT 116 (human colorectal carcinoma) cells, minimal toxicity toward NIH‐3T3 (mouse embryonic fibroblast) cells, effective DPPH radical scavenging activity, and pronounced antimicrobial effects. Complexes 1 and 2 exhibited IC 50 values of 16.55 ± 0.05 μM and 13.99 ± 0.05 μM, respectively, comparable to cisplatin (IC 50 = 7.05 ± 0.05 μM). These findings highlight the dual potential of the synthesized Ni(II) complexes as efficient photocatalysts and promising candidates for biomedical applications.
Synthesis and Characterization of Macrocyclic Ferrocenyl Chalcone and Their Co(II) and Cu(II) Complexes: Photonuclease and Photocytotoxicity Murugan Sethupathi, Nallathambi Sengottuvelan, Kumar Ponnuchamy, Mandla Vincent Khumalo Applied Organometallic Chemistry, 2025 Ferrocenyl chalcone complex (Fc2L) has been synthesized from the condensation of 3,4:10,11‐dibenzo‐1,13[N,N′‐bis{(3‐formyl‐2‐hydroxy‐5‐methyl)benzyl}]‐5,9‐dioxocyclohexa decane (the precursor compound) with acetyl ferrocene. The Co(II) and Cu(II) Complexes (CoFc2L [1] and CuFc2L [2]) were synthesized from the ferrocenyl chalcone (Fc2L) with metal chloride salts and characterized by various physicochemical techniques (UV–Vis, FT‐IR, 1H NMR,13C NMR, ESI‐MS, and TGA). The electrochemical studies exhibit a quasireversible reduction wave with Epc near −1.02 V for Complex 1 and −0.95 V for Complex 2. TGA analysis proposed that Complexes 1 and 2 showed thermal stability. The calf thymus DNA (CT‐DNA) binding studies of the complexes were examined by spectral studies and electrochemical measurements. The absorption spectrum analyses demonstrated that Complexes 1 and 2 have intrinsic binding strengths of 7.5 × 105 M−1 and 9.18 × 105 M−1, respectively, and bind to CT‐DNA via an intercalative binding mechanism. The pUC19 DNA cleavage studies of the complexes using gel electrophoresis assay were performed in the presence of MPA for Complex 1 and in the presence of Asc for Complex 2. After radiation exposure, the plasmid SC DNA in both complexes was completely cleaved into NC DNA and photo nick DNA via a singlet oxygen pathway. The antimicrobial activity of Complexes 1 and 2 exhibits better bacterial and fungal growth inhibition at the higher study concentration. The complexes' cytotoxicity was evaluated on MDA‐MB‐231 breast cancer cells, exhibiting IC50 values of 10, 50, and 5, 25 μg/mL under dark and light irradiation, respectively. The fluorescence microscopy analysis of cell morphology studies using AO/EB dual labeling, propidium iodide (PI) staining, and the Hoechst staining on MDA‐MB‐231 cancer cells revealed a significant increase in cell mortality during irradiation due to the photodynamic effect. The present study demonstrates that Complexes 1 and 2 without radiation in breast cancer cells stimulate intrinsically mediated apoptosis. In the meantime, radiation triggers Complexes 1 and 2 intrinsic‐ and extrinsic‐mediated apoptosis pathways. The biotoxicity assay using Artemia nauplii was evaluated for Complexes 1 and 2 to identify its biocompatibility.
Isoquinoline-Fused Benzimidazoles Based Highly Selective Fluorogenic Receptors for Detection of Cu2+, Fe3+, and Cl− Ions: Cytotoxicity and HepG2 Cancer Cell Imaging Parvathavarthini Murugaperumal, Venkatramani Sriram, Sengottuvelan Nallathambi, Siva Ayyanar, Ashokkumar Balasubramaniem Luminescence, 2025 An efficient isoquinoline‐fused benzimidazole–based “turn‐on” fluorescence receptor 9,10‐bis(2‐phenylhydrazineyl)‐7H‐benzo[de]imidazo[2,1‐a]isoquinolin‐7‐one OXPH(ANQ) and “turn‐off” fluorescence receptor 9,10‐bis((3‐(1H‐imidazol‐1‐yl)propyl)amino)‐7H‐benzo[de]imidazo[2,1‐a]isoquinolin‐7‐one OXPID(ANQ) were prepared and characterized by various spectral techniques. The sensing behavior of receptors was demonstrated by UV–vis and fluorescence experiments, and naked‐eye detection exhibited prominent visual emission color change toward Cu2+/Cl− and Fe3+ over other testing cations/anions in DMSO:water (9:1, ν/v) solution. The 1:1 binding stoichiometry was confirmed by Job's plot, FT‐IR, mass spectral titration, and also DFT studies with target ions as evidence for the binding nature of OXPH(ANQ)/OXPID(ANQ) with Cu2+/Cl− and Fe3+ ions, respectively. Limits of detection for OXPH(ANQ) with Cu2+/Cl− ions were of 4.50 and 4.91 μM, and OXPID(ANQ) with Fe3+ ions were of 5.06 μM. Interestingly, chemosensors OXPH(ANQ)/OXPID(ANQ) applied to intracellular image of Cu2+/Cl− and Fe3+ ions in living cells of HepG2 (Liver cancer cells) via confocal fluorescence microscopy technique at physiological environmental and also utilized for antimicrobial activity.
Macrocyclic Metal Complexes as Potential Tools for Anticancer Applications Parvathavarthini Murugaperumal, Kannan Subburaj, Sengottuvelan Nallathambi ACS Symposium Series, 2025 Anticancer medications based on metals are essential to clinical therapy. Traditional platinum-based anticancer medications bind to DNA and damage it in different ways, triggering apoptosis in cancer cells. The strategy of pharmacophore conjugation is a crucial approach in the development of multi-targeting pharmaceuticals. The synthesis and initial biological investigations of unique trackable complexes are presented in this chapter. These investigations involved coupling the metal complex to an imaging probe, such as a chelating agent of boron-dipyrromethene (BODIPY), porphyrin, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) for radioisotopic imaging PET (positron emission tomography) or SPECT (single photon emission computed tomography). This chapter provide an overview of anticancer activity of copper, gold, osmium, indium, cobalt, iridium and Ruthenium-based complexes, including their mechanisms of action and strategies used to increase their anticancer efficacy. For the future development of therapeutics based on non-platinum metal complexes like Ru(II), Os(II), or Au(I) derivatives, as well as for understanding the mechanisms underlying these metal-based medications, the design of trackable anticancer agents is of great interest.
6-chloro-2-(4-methoxyphenyl)-4-phenylquinoline B. Saravanan, V. Thamilarasan, N. Sengottuvelan, G. Chakkaravarthi, V. Manivannan Acta Crystallographica Section E Structure Reports Online, 2013
1,2-bis(2-hydroxy-5-methylbenzylidene)hydrazine B. Saravanan, A. Jayamani, N. Sengottuvelan, G. Chakkaravarthi, V. Manivannan Acta Crystallographica Section E Structure Reports Online, 2013
Synthesis, spectral and electrochemical studies of novel porphyrin bound tetranuclear acyclic manganese(III) and copper(II) complexes Indian Journal of Chemical Technology, 2002
