Electrochemistry, Inorganic Chemistry, Catalysis, Renewable Energy, Sustainability and the Environment
17
Scopus Publications
Scopus Publications
Density Functional Theory-Guided Photo-Triggered Anticancer Activity of Curcumin-Based Zinc(II) Complexes Rajesh Kushwaha, Virendra Singh, Silda Peters, Ashish K. Yadav, Dependu Dolui, et al. Journal of Physical Chemistry B, 2023 Photodynamic therapy (PDT) has evolved as a new therapeutic modality for cancer treatment with fewer side effects and drug resistance. Curcumin exhibits PDT activity, but its low bioavailability restricts its clinical application. Here, the bioavailability of curcumin was increased by its complex formation with the Zn(II) center. For a structure-activity relationship study, Zn(II)-based complexes (1-3) comprising N^N-based ligands (2,2'-bipyridine in 1 and 2 or 1,10-phenanthroline in 3) and O^O-based ligands (acetylacetone in 1, monoanionic curcumin in 2 and 3) were synthesized and thoroughly characterized. The X-ray structure of the control complex, 1, indicated a square pyramidal shape of the molecules. Photophysical and TD-DFT studies indicated the potential of 2 and 3 as good visible light type-II photosensitizers for PDT. Guided by the TD-DFT studies, the low-energy visible light-triggered singlet oxygen (1O2) generation efficacy of 2 and 3 was explored in solution and in cancer cells. As predicted by the TD-DFT calculations, these complexes produced 1O2 efficiently in the cytosol of MCF-7 cancer cells and ultimately displayed excellent apoptotic anticancer activity in the presence of light. Moreover, the molecular docking investigation showed that complexes 2 and 3 have very good binding affinities with caspase-9 and p-53 proteins and could activate them for cellular apoptosis. Further molecular dynamics simulations confirmed the stability of 3 in the caspase-9 protein binding site.
Energy-efficient CO2/CO interconversion by homogeneous copper-based molecular catalysts Somnath Guria, Dependu Dolui, Chandan Das, Santanu Ghorai, Vikram Vishal, et al. Nature Communications, 2023 Facile conversion of CO2 to commercially viable carbon feedstocks offer a unique way to adopt a net-zero carbon scenario. Synthetic CO2-reducing catalysts have rarely exhibited energy-efficient and selective CO2 conversion. Here, the carbon monoxide dehydrogenase (CODH) enzyme blueprint is imitated by a molecular copper complex coordinated by redox-active ligands. This strategy has unveiled one of the rarest examples of synthetic molecular complex-driven reversible CO2reduction/CO oxidation catalysis under regulated conditions, a hallmark of natural enzymes. The inclusion of a proton-exchanging amine groups in the periphery of the copper complex provides the leeway to modulate the biases of catalysts toward CO2 reduction and CO oxidation in organic and aqueous media. The detailed spectroelectrochemical analysis confirms the synchronous participation of copper and redox-active ligands along with the peripheral amines during this energy-efficient CO2reduction/CO oxidation. This finding can be vital in abating the carbon footprint-free in multiple industrial processes.
1D/2D interface engineering of a CoPc-C3N4 heterostructure for boosting the nitrogen reduction reaction to NH3 Sourav Paul, Sougata Sarkar, Dependu Dolui, Debashrita Sarkar, Marc Robert, et al. Dalton Transactions, 2023 Exfoliated C3N4 sheets were employed to wrap the CoPc nanotubes (NTs) to synthesize the electrocatalyst; the CoPc–C3N4 system showed excellent nitrogen reduction to ammonia with a yield rate of 423.8 μg h−1 mgcat−1 and a FE of 33% at −0.2 V vs. RHE.
Post-synthetic modulation of UiO-66-NH2 with a cobaloxime catalyst for efficient hydrogen production Saddam Sk, Sandip Prabhakar Shelake, Dependu Dolui, Suhana Karim, Rajib Ghosh, et al. Energy Advances, 2023 Post synthetically-modified UiO-66-NH2 with a molecular cobaloxime [Co(DMG)2Cl2] (DMG = dimethylglyoxime) catalyst displays excellent photo-(404 μmol g−1 h−1) and electrocatalytic H2 evolution activity in an aqueous solution.
Polypyridyl CoII-Curcumin Complexes as Photoactivated Anticancer and Antibacterial Agents Ashish Kumar Yadav, Virendra Singh, Rajesh Kushwaha, Dependu Dolui, Rohit Rai, et al. Chembiochem, 2023 Four new Co(II) complexes viz., [Co(bpy)2(acac)]Cl (1), [Co(phen)2(acac)]Cl (2), [Co(bpy)2(cur)]Cl (3), [Co(phen)2(cur)]Cl (4), where bpy = 2,2'-bipyridine (1 and 3), phen = 1,10-phenanthroline (2 and 4), acac = acetylacetonate (1 and 2), cur = curcumin monoanion (3 and 4) were designed, synthesized and fully characterized. The X-ray crystal structures of 1 and 2 indicated that CoN4O2 core has a distorted octahedral geometry. The photoactivity of these complexes was tuned by varying the π conjugation in the ligands. 3 and 4 depicted an intense absorption band near 435 nm, which made them useful as visible-light PDT agents. Curcumin complexes 3 and 4 showed fluorescence with λemi = ca. 565 nm. This fluorescence was useful to study their intracellular uptake and localization in MCF-7 cancer cells. The acetylacetonate complexes (1 and 2) are used as control complexes to understand the role of curcumin. The white light-triggered anticancer profiles of the cytosol targeting complexes 3 and 4 were investigated in detail. These non-dark toxic complexes displayed significant apoptotic photo-cytotoxicity (under visible light) against MCF-7 cells via ROS generation. The control complexes 1 and 2 did not induce significant cell death in light and dark. Interestingly, 1-4 produced a remarkable antibacterial response on light exposure. Overall, the reported results here can increase the boundary of the Co(II)-based anticancer and antibacterial drug development.
A Simulation Independent Analysis of Single- and Multi-Component cw ESR Spectra Aritro Sinha Roy, Boris Dzikovski, Dependu Dolui, Olga Makhlynets, Arnab Dutta, et al. Magnetochemistry, 2023 The accurate analysis of continuous-wave electron spin resonance (cw ESR) spectra of biological or organic free-radicals and paramagnetic metal complexes is key to understanding their structure–function relationships and electrochemical properties. The current methods of analysis based on simulations often fail to extract the spectral information accurately. In addition, such analyses are highly sensitive to spectral resolution and artifacts, users’ defined input parameters and spectral complexity. We introduce a simulation-independent spectral analysis approach that enables broader application of ESR. We use a wavelet packet transform-based method for extracting g values and hyperfine (A) constants directly from cw ESR spectra. We show that our method overcomes the challenges associated with simulation-based methods for analyzing poorly/partially resolved and unresolved spectra, which is common in most cases. The accuracy and consistency of the method are demonstrated on a series of experimental spectra of organic radicals and copper–nitrogen complexes. We showed that for a two-component system, the method identifies their individual spectral features even at a relative concentration of 5% for the minor component.
