[en] Impressive rate of solar water oxidation to molecular oxygen (O₂ ) has been demonstrated on nanorods (NRs) of Ce_0.9Ti_0.1O₂ (CT-NR) and Au-deposited CT-NR (Au-CT-NR) photocatalysts with a sacrificial agent (Fe³⁺) and in plain water in one sun condition, direct sunlight and with λ ≥455 nm. Probably the highest O₂ yield of 11 mmol/h.g was observed with Au-CT-NR thin film in plain water in direct sunlight, with no sacrificial agent or applied potential. Photoelectrochemical measurements demonstrate a marked reduction in oxidation onset potential of Au-CT-NR by 150 mV with stable photocurrent (0.75 mA/ cm² ), compared to CT-NR (0.23 mA/cm² ), indicating the operative of plasmon-induced resonant energy transfer (PIRET) process. Effective electron quenching by nanogold and hence low recombination in the depletion region is a critical step for the observation of a high rate of oxygen evolution. In addition to this, a predominant change in the nature of the valence band from O-2p dominated on CeO₂ to Ce-4f dominated with CT-NR (due to Ti⁴⁺ introduction in CeO₂ ), the efficient light absorption of photocatalysts in thin-film form, functional and effective PIRET process, and facile E F alignment, enhances the oxygen evolution with Au-CT-NR in direct sunlight and make it highly sustainable. A possible mechanism of water oxidation is proposed from the observed experimental findings. (author)

[en] Graphene quantum dots (GQDs), a zero-dimensional material, are emerging as a potential fluorescent probe with a wide range of applications, particularly bio-imaging and optical sensing. In this work,we have fabricated the blue-emitting Graphene Quantum Dots (GQDs) and utilized as for free bilirubin (BR)detection. Under optimal conditions, the fluorescence of GQDs was quenched linearly with the successive addition of BR concentrations. The probe exhibited a wide linear range (40.53-237.55 μM), low detection limit (9μM), high selectivity, and rapid response towards free BR. The drastic quenching in the fluorescence intensity of GQDs with the addition of BR is due to Forster Resonance Energy Transfer (FRET) between GQDs and bilirubin. The efficiency of energy transfer between GQD and BR was determined as 43%.Therefore, this free BR sensing platform using GQDs may prove useful in the diagnosis of jaundice. Our study opens up the possibility of designing a low-cost biosensor that will be suitable for a real sample study. (author)

[en] Reaction of [(arene)MCl 2 ]2 with bidentate 4, 5-diazafluorene-9-one (dafo) and derived Schiff- base ligands (L1–L3) in the presence of ammonium hexafluorophosphate yielded mononuclear cationic complexes having general formula [(arene)MLCl]PF 6 {M = Ru, arene = benzene (1, 5, 9); M = Ru, arene = p- cymene (4, 8); M = Rh, arene = Cp* (2, 6, 10); M = Ir, arene = Cp* (3, 7, 11); L = 4, 5-diazafluorene-9-one (L1), N-(4, 5-diazafluoren-9-ylidene)aniline (L2), N-(4, 5-diazafluoren-9-ylidene)phenyl hydrazine (L3)}. All these complexes were isolated as hexafluorophosphate salts and characterized by spectral and analytical techniques such as FT-IR, UV-vis, NMR spectroscopy and ESI-Mass spectrometry. Complexes 1-3 were characterized by X-ray crystallographic studies, which indicated NN0 bidentate coordination of the ligands through pyridine nitrogen atoms of the ligand. To evaluate the biological properties of these complexes, antibacterial and antioxidant experiments have been carried out. The complexes 8, 9 and 11 exhibited antibacterial activity against Gram-positive bacteria. Results also show that the compounds possess prominent antioxidant activity against DPPH radicals. (author)

[en] Novel Ni-Pd and Cu-Pd bimetallic nano alloys was designed and heterogenized on the highly robust ABPBI [poly(2,5-benzimidazole)] polymer in high yields using NaBH₄ as reducing agent. These were versatile ligand free catalysts for the Mizoroki–Heck reaction and Suzuki–Miyaura coupling. The bimetallic Ni-Pd-ABPBI catalyst for the Mizoroki–Heck reaction of 4-iodo anisole could be recycled 5 times with high yields. Aryl bromides could also be activated for the Mizoroki–Heck reaction using Cu-Pd-ABPBI NP catalysts, with moderate yields. (author)

[en] The heterobimetallic Ru(II)-Pt(II) polypyridyl complexes [Ru(bpy)₂(BPIMBp)PtCl₂]²⁺ (3) and [Ru(phen)₂(BPIMBp)PtCl₂]²⁺ (4) with their parent complexes [Ru(bpy)₂BPIMBp]²⁺(1) and [Ru(phen)₂BPIMBp]²⁺ (2) possessing bridging ligand (BPIMBp = 1,4′-Bis-{(2-pyridin-2-yl)-1H-imidazol-1-yl)methyl}-1,1′-biphenyl) were used for photo cytotoxicity against MCF-7 cells.The parent ruthenium complexes (complexes 1-2) exhibited a negligible increase in viscosity of DNA while hetero bimetallic Ru(II)-Pt(II) system exhibited a decrease in viscosity of DNA, indicating covalent interaction (through cis-PtCl₂ unit). The Ru(II)-Pt(II) system co-precipitated with CT-DNA confirmed the covalent binding. In electrophoretic mobility studies, the interaction of Ru(II)-Pt(II) system with plasmid DNA led to retardation of negative supercoiled form, followed by positive supercoiled migration in the dark that indicated the ability to form covalent adducts with DNA similar to cisplatin. The complexes 1-4 showed enhanced photo cleavage of plasmid DNA on blue light (~450 nm) irradiation. In a cell-based study, all the complexes exhibited photo activated cytotoxicity in MCF-7 cancer cells when exposed to visible light of ~450 nm as compared to low toxicity in absence of irradiation. Additionally, the complexes containing platinum showed induction of autophagy in GFP-LC3 expressing MCF-7 cells. Overall our study shows that the inclusion of photo sensitizer Ru(II) polypyridyl complexes to cis-PtCl₂ moiety improves anticancer properties of complexes. (author)

[en] Quinone-based macrocyclic compounds have been proposed as promising electrode materials for rechargeable lithium-ion batteries (LIBs). To improve the electrochemical performance, in this paper, two heteroatom-bridged pillar[4]quinones (namely, oxa- and thia-pillar[4]quinones) are presented as active cathode materials for LIBs. The geometry structures, electronic structural properties, and electrochemical properties of these new species are calculated by Density Functional Theory (DFT) at the M06-2X/6-31G(d,p) level of theory. Two heteroatom-bridged pillar[4]quinones possess higher theoretical specific capacity (659 mA h g^-1 and 582 mA h ^g-1 for oxa- and thia- pillar[4]quinones, respectively) than that of parental pillar[4]quinone (446 mA h ^g-1). The electrochemical performances of oxa- and thia-pil-lar[4]quinones are predicted theoretically to be superior to those of pillar[4]quinone as cathode material for LIBs. Compared with oxa-pillar[4]quinone, thia-pillar[4]quinone is predicted to be slightly more suitable as cathode electrode material. These results may provide fresh ideas and guidelines for enhancing the performance of quinones organic electrode materials for LIBs. (author)

[en] Pristine and indium doped magnesium ferrite nanoparticles have been prepared by the sol-gel method. The phase formation has been confirmed from XRD (X-ray diffraction) whereas nano size has been displayed through TEM (Transmission Electron Microscope) images. BET (Brunauer–Emmett–Teller)analysis showed an increase in surface area for the indium doped sample compared to pristine magnesium ferrite. The superparamagnetic nature of nanoparticles has been observed from M–H studies carried on VSM and these have been efficiently employed as a catalyst in organic transformation such as quinazolinone synthesis and Henry reaction. The indium doped magnesium ferrite catalyst has been found to be highly active and recyclable in nature. The high surface area and Lewis acidity govern their catalytic performance whereas magnetic nature makes the separation easier. (author)

[en] Five perovskite materials of the general formula La_1-xSr_xMn_1-yZn_yO₃ (x = 0, 1, 2, 3, and y = 0,2) were successfully synthesized by the citric acid sol-gel route and characterized by scanning electronic microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Brunner-Emmet-Teller (BET) technique and X-ray photoelectron spectroscopy (XPS). The materials were employed as heterogeneous catalysts in the Hantzsch reaction, producing 1,4-dihydropyridine derivatives. Incorporating Zn into the parent perovskite LaMnO₃ improved the catalytic activity, which was greatly enhanced by the simultaneous introduction of Sr. In addition to the positive effect of Zn and Sr incorporation, the results also showed that the catalytic activity was related to the surface Mn⁴⁺ content and acidic character. The La_0.9-Sr_0.1Mn_0.8Zn_0.2O₃ catalyst was recycled and reused four times after demonstrating significant catalytic activity in a polar protic solvent (ethanol). After four cycles of use, the catalyst did not exhibit a significant reduction in catalytic activity, despite the formation of some secondary phases revealed by XRD and XPS analyses. (author)

[en] he emerging area of carbon-based nanoparticles (NPs) and their increased usage in the biomedical field necessitate checking their biocompatibility and permeation pathway across the cell membrane. In this study, we explore the permeation pathway of two NPs - a well-studied fullerene (C₆₀ ) and a pristine carbon dot (CD) across a model Palmitoyloleoylphosphatidylcholine (POPC) lipid membrane. Both constrained and unconstrained all-atom molecular dynamics (MD) simulations are carried out to understand their permeation mechanism. C₆₀ permeates the bilayer via passive permeation and stays inside the hydrophobic core, while the CD does not show any sign of permeation across the membrane throughout the simulation time window. The free energy profiles for the permeation are calculated using the umbrella sampling method. The huge barrier for the permeation of the CD is confirmed from the PMF profiles, while the free energy minima for the permeation of C₆₀ are located in the bilayer interior. This mode of permeation of C₆₀ can hint at its toxic nature to cell membranes widely investigated in the past. The structural properties of the bilayer are also analyzed, and on a global scale, it shows no significant mechanical damage to the membrane. Thus, our study details the molecular level interaction of pristine carbon-based NPs with a lipid bilayer. (author)

[en] Corrosion inhibition of carbon steel in sulfuric acid solution was performed by three synthesized products named 2-(butylamino)-4-phenylnicotinonitrile (BAPN), 2-(propylamino)-4-phenylnicotinonitrile, and 2-(methylamino)-4-phenylnicotinonitrile using weight-loss method and scanning electron microscopy (SEM). The temperature impact on the inhibition mechanism of the synthesized inhibitors of the carbon steel surface was investigated at various temperatures (20–50 °C) where the inhibitive efficiency diminished with increasing temperatures. The maximum IE of 97.45% was achieved at a temperature of 20 °C, the concentration of BAPN inhibitor of 5x10^-4 M, and H₂SO₄ acid concentration of 0.5 M. The adsorption of inhibitors studied onto the carbon steel surface obeys the Langmuir adsorption isotherm. The SEM surface analysis showed the formation of a protective organic film on the steel surface. The quantum chemical calculations (DFT) supported the experimental results and showed that the inhibition efficiency also depends on the structure of the inhibitor. (author)