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In this study, 8, 25 and 50 wt% Fe3O4@activated carbon (AC) catalysts were prepared by simple coprecipitation method. The efficiency of the catalysts for the advanced Fenton's oxidation process using methylene blue (MB) as a model substrate was tested. Both modified and unmodified activated carbon catalysts exhibited similar activity towards the Fenton's oxidation process. Therefore, it is difficult to identify the role of the catalyst in this dye removal process. Hence, we proposed a new methodology to remove the MB by adopting the adsorption process initially, followed by the Fenton's oxidation process. The proposed process significantly improved the methylene blue decomposition reaction over the 25 wt% Fe3O4@AC catalyst. However, this trend was not seen in pure activated carbon and Fe3O4@AC (8 and 50 wt%) catalysts due to the instability of the material in the oxidizing medium. The possible reason for the deactivation of the catalysts was evaluated from lattice strain calculations, as derived from the modified W–H models (Uniform Deformational Model (UDM), Uniform Stress Deformation Model (USDM) and Uniform Deformation Energy Density Model (UDEDM)). These results provided a quantitative relationship between the experimentally calculated lattice strain values and Fenton's catalytic activity. Furthermore, the optimized strain value and crystalite size of Fe3O4 on the activated carbon matrix are responsible for the high catalytic activity.

In this study, 8, 25 and 50 wt% Fe

Conjugated dendrimers decorated with 5,5-difluoro-10-(4-(prop-2-ynyloxy)phenyl)-5H-dipyrrolo[1,2-c:1′,2′-f][1,3,2]diazaborinin-4-ium-5-uide, usually known as boron dipyrromethene (BODIPY), have been synthesized and their application as photosensitizer in dye sensitized solar cells (DSSCs) has been evaluated. Third generation triazole bridged BODIPY dendrimers show higher light energy harvesting efficiency of 2.5% better than the first and second generation dendrimers, when used as a dye material in solar cells. The current intensity increases with an increase in the generation of the dendrimer as revealed by cyclic voltammetry. Fluorescence decay analysis shows that the relaxation times τ1 and τ2 increase as the dendrimer generation increases, however τ2 for the third generation dendrimer decreases because of fluorescence quenching due to molecular crowding.

A convenient and efficient method for the regioselective macrocyclization of triazole bridged spiropyrrolidine-oxindole, and bis-spiropyrrolizidine-oxindole derivatives was accomplished through intra and self-intermolecular [3 + 2] cycloaddition of azomethine ylides. The chalcone isatin precursors 9a–i required for the click reaction were obtained from the reaction of N-alkylazidoisatin 4 and propargyloxy chalcone 8a–i which in turn were obtained by the aldol condensation of propargyloxy salicylaldehyde 6 and substituted methyl ketones 7a–i. The regio- and stereochemical outcome of the cycloadducts were assigned based on 2D NMR and confirmed by single crystal XRD analysis. High efficiency, mild reaction conditions, high regio- and stereoselectivity, atom economy and operational simplicity are the exemplary advantages of the employed macrocyclization procedure.

(S)-BINOL cored dendrimers 1–3 with a rhodamine B surface group and triazole bridging unit were synthesized up to second generation in good yield by convergent synthesis through click chemistry. The chiro-optical property of the synthesized dendrimers reveals that the specific rotation increases as the order of dendrimer increases from the zeroth generation to the second generation dendrimer. The electrochemical properties of the dendrimers 1, 2 and 3 showed quasi-reversible behavior in cyclic voltammetry. The anticancer activity against human hepatocellular carcinoma cell for the second generation dendrimer 3 was found to be better than that for the lower generation dendrimers 1 and 2.

A series of organometallic Ru(II)-arene complexes of the type [(η6-p-cymene)Ru(L)Cl](BF4) 1–6, where L is 3-phenyl-1-pyridin-2-yl-imidazo[1,5-a]pyridine (L1), dimethyl-[4-(1-pyridin-2-yl-imidazo[1,5-a]pyridin-3-yl)phenyl]-amine (L2), diphenyl-[4-(1-pyridin-2-yl-imidazo[1,5-a]pyridin-3-yl)phenyl]amine (L3), 9-[4-(1-pyridin-2-yl-imidazo-[1,5-a]pyridin-3-yl)-phenyl]-9H-carbazole (L4), 9-ethyl-3-(1-pyridin-2-yl-imidazo-[1,5-a]pyridin-3-yl)-9H-carbazole (L5), and 10-ethyl-3-(1-pyridin-2-yl-imidazo[1,5-a]pyridin-3-yl)-10H-phenothiazine (L6), has been isolated and characterised by elemental analysis, ESI-MS, NMR and cyclic voltammetry. The photophysical properties of the complexes have been studied by electronic absorption and emission spectral techniques. All the ligands exhibit tuneable photoluminescence behaviour with the emission maximum spanning through the visible region (475–670 nm) in dichloromethane while all the complexes are emissive in acetonitrile. The single crystal X-ray structures of 2, 3 and 4 reveal that the complexes have a “piano stool” coordination geometry, comprising one π-bonded arene centroid, two σ-bonded nitrogen atoms from the chelating ligand and one Cl− ion. From DNA induced EthBr emission quenching experiments the apparent DNA binding constants of the complexes (Kapp) have been evaluated, which follows the order, 2 (1.3) 100 μM), exhibit in vitro cytotoxicity against A549 small lung cancer cell lines higher than cisplatin (∼69 μM), as revealed by both MTT (11.8–18.1 μM) and crystal violet staining (12.7–23.5 μM) assays, which is in agreement with their DNA and BSA binding affinity. Also, the complexes 3–6 cause higher cell death mainly through the apoptotic mode, as revealed by the observation of a higher percentage of apoptotic cells in AO/EB (36–43%) and Annexin V-Cy3 (36–45%) stained cancer cells.

Rate coefficients for the reaction of chlorine atoms with 2,3-dimethyl-1,3-butadiene were measured over the temperature range of 269–393 K by using a relative rate experimental method with reference to isoprene and 1-pentene. Concentrations of the 2,3-dimethyl-1,3-butadiene and reference compounds were monitored by gas chromatography equipped with a Flame Ionization Detector (FID). The obtained rate coefficient for the reaction of 2,3-dimethyl-1,3-butadiene with Cl atoms at 298 K is k = (4.48 ± 0.46) × 10−10 cm3 per molecule per s, which is in good agreement with the reported rate coefficient at 298 K and 760 Torr. The obtained temperature dependent rate coefficient is k2,3-dimethyl-1,3-butadiene+Cl (269–363 K) = (4.59 ± 0.67) × 10−11 exp[(663.13 ± 45.8)/T] cm3 per molecule per s. To further understand the reaction mechanism of butadienes with Cl atoms, theoretical calculations were performed for the reactions of 2-methyl-1,3-butadiene (isoprene) and 2,3-dimethyl-1,3-butadiene with Cl atoms as a function of temperature using Conventional Transition State Theory (CTST) in combination with QCISD(T), CCSD(T) and MP2 levels of theory with different basis sets. The theoretically calculated temperature dependent rate coefficient is k2,3-dimethyl-1,3-butadiene+Cl (200–400 K) = (4.12 ± 0.38) × 10−12 exp[(1419.2 ± 26)/T] cm3 per molecule per s which is in excellent agreement with our experimentally measured rate coefficients. The rate coefficient was observed to be increasing with the substitution of hydrogen atoms by methyl groups.

Anticancer targeted ruthenium(II) complex units containing bpy(2,2′-bipyridine), phen(1,10-phenanthroline) or 2,9-dmp(2,9-dimethyl 1,10-phenanthroline) anchored on a branched polyethylenimine molecule (RuL-BPEI) were synthesised. These complexes are highly stable, emissive, redox active and show a quasi-reversible response in cyclic voltammetry. Synthesised compounds were characterized by infra-red, UV-visible, NMR, CHN, and AES analysis methods. The interaction of these RuL-BPEI samples with calf thymus DNA was explored using electronic absorption spectroscopy, emission spectroscopy, cyclic voltammetry and circular dichroism techniques. Antimicrobial activities of these polymer metal complexes have been investigated against a range of various bacteria, including clinically resistant microbes. And also anticancer properties have been tested with MCF-7 breast cancer cell lines. All results were positive.

Porphyrin-cored bile acid dendrimers containing deoxymethyl cholate and methyl cholate units at the periphery, have been synthesized by convergent methodology using a click chemistry approach and characterized by 1H and 13C NMR and MALDI-TOF MS data. The absorption–emission behavior of dendrimers and its modulation under the influence of the dendritic environment is also investigated. The therapeutic efficacy of the bile acid dendrimers for the inhibition of the growth of tumor cells (MIA PaCa-2) increases as the dendrimer generation increases.

The fabrication of efficient sorbents having high selectivity and sorption capacity from natural products has attracted considerable interest due to practical applications in oil spill clean-ups and recovery of spilled oil. Our work presents the preparation of a natural sorbent material with superhydrophobic character, excellent selectivity and high oil sorption capacity using silk fibroin fibers, where the fibers were surface modified with octadecylamine via a simple synthetic approach. The sorbent fibers were found to possess superhydrophobic character with a static water contact angle of 150 ± 3°. The results of oil sorption experiments on oil–water mixtures infer that the modified fibers possess excellent selectivity as well as oil sorption ability, where the oil sorption capacity (OSC) of the material was found to be 46.83 g g−1 for crude oil and 84.14 g g−1 for motor oil. Moreover, the oil sorption capacity of our fiber for motor oil is almost 8 times higher than natural wool, and twice higher than the silkworm cocoon waste. The modified fibers have significantly higher OSC values for crude oil (3.5 times higher) than any wool based sorbents. The suitability of the material over a wide pH range of 3–11 substantiates its advantage in oil sorption even in any corrosive environment. Further, the oil recovery and reusability of the fibers were tested to investigate their applicability for repeatable usage in oil spill clean-up application.

In the present study, an attempt has been made to utilize a Ru(II)-complex (dye)-sensitized ZnO hybrid along with a Pt(II) salt for the visible light aided photoreduction of 4-nitrophenol. The dye, bis(2,2′-bipyridyl)(4,4′-dicarboxy-2,2′-bipyridyl)ruthenium(II) chloride, is used as a sensitizer for ZnO. The photocatalyst, Ru(II) dye–ZnO, has been characterized by XRD, FTIR, DRS, SEM, EDX and XPS. A kinetic study of the photoreduction reaction was carried out under visible light irradiation (CFL 45 W) with different concentrations of Pt(II) ions, without changing the 4-nitrophenol concentration. The reduced percentage reached a maximum of 55–60%, in the presence of the Pt(II) salt at a concentration of 2.5 × 10−4 mol%. Control studies were done (in the presence of light and dark) to establish the photoactivity of the prepared photocatalyst. A series of experiments have been conducted to understand the mechanistic aspects of the photoreduction process, and it is identified that the photoreduction of 4-nitrophenol proceeds through an electron transfer process.

Anthracene conjugated blue light emitting glycodendrimers 1, 2 and 3 were synthesized using Cu(I) catalyzed click chemistry. All of the anthracene conjugated blue light emitting glycodendrimers have enhanced photophysical, electrochemical and laser properties, from the lower to the higher generation dendrimers. Blue light emitting higher generation glycodendrimer 3 shows a longer life time (11.2 ns) than the lower generation glycodendrimers 1 and 2 due to the presence of a larger number of triazole bridging units and multivalent glucose units.

Fluorescent amidoanthracenophanes 1, 2, 3 and 4 were obtained from the various aromatic diacid chlorides and diamino precyclophane by simple acylation. All the synthesized amidoanthracenophanes 1, 2, 3 and 4 show three intense fluorescence bands between 401 and 402, 426 and 429, and at 449 to 451 nm, and exhibit two/three oxidation reduction peaks in the cyclic voltammetry which is characteristic of fluorophoric anthracene units.

Gold nanoparticle decorated glycodendrimers 1, 2, 3 and 4 were synthesized using a click chemistry approach. Gold nanoparticles (NPs) were synthesized in good yields either by stabilization or encapsulation of the triazolyl glycodendrimers. Gold nanoparticles were stabilized (DSNPs) by the zeroth generation dendrimer and encapsulated (DENPs) by the first generation glycodendrimer. The Au–DSNPs and Au–DENPs were characterized using UV-Vis spectroscopy and high resolution transmission electron microscopy (HRTEM) which shows that Au–DSNPs and Au–DENPs have an average of diameter 7.2 nm and 4.0 nm, respectively. The catalytic activity of Au–DSNPs for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) with NaBH4 in aqueous conditions was examined using UV-Vis spectroscopy.

New chiral L-valine-derived Schiff base complexes with the bioactive heterocyclic ligand scaffold pyrazole (Hpz) were designed and synthesized with a view to find their potential as anticancer chemotherapeutic drug candidates. The monometallic chemical entities CuII (1) and ZnII (2), and heterobimetallic CuII–SnIV (3), and ZnII–SnIV (4) were synthesized and characterized adopting various spectroscopic (UV-vis, IR, 1H 13C and 119Sn NMR, EPR and ESI-MS) and analytical methods. In vitro, CT-DNA-binding profiles of 1–4 were studied by UV-vis, fluorescence spectroscopy, and circular dichroism. The results display the significantly higher binding affinity of heterobimetallic complexes 3 and 4 than monometallic complexes 1 and 2. This could be attributed to the dual binding mode facilitating a preferential electrostatic interaction via SnIV towards the surface phosphate oxygen of the sugar–phosphate backbone of the DNA double helix, in addition to the covalent overlap of CuII to N7 of the guanine of the DNA. Moreover, complex 3 exhibited significantly efficient DNA cleavage activity involving the formation of the superoxide radical as well as the hydroxyl radical as the reactive species. The SOD-like activity of 3 and 4 was evaluated using a xanthine/xanthine oxidase assay, which showed SOD activity in the micromolar range for both the heterobimetallic complexes viz., (IC50) 0.082 μM for 3 and 12 μM for 4. Furthermore, 3 showed high inhibitory activity against Topo-Iα at a concentration of 20 μM as IC50, suggesting that complex 3 is an efficient DNA cleaving agent. In vitro studies on the anticancer activity against the HepG2 hepatocellular carcinoma cell line revealed that both complexes 3 and 4 have the capability to kill the chosen cancer cell, but the efficiency of complex 3 is 10 times higher than 4. The mode of cell death induced by complex 3 is primarily apoptosis as revealed by AO/EB staining, Hoechst 33258 staining, and assessment of the mitochondrial trans-membrane potential.

Thermal decomposition of methyl butanoate (MB) diluted in argon was studied behind reflected shock waves in the temperature range of 1229-1427 K using a single pulse shock tube (SPST). The post shock mixtures were analyzed quantitatively using gas chromatography (GC) and qualitatively using Fourier-transform infrared (FTIR) spectroscopy. Methane (CH4), ethylene (C2H4), and acetylene (C2H2) were the major decomposition products. The minor products are ethane (C2H6), propylene (C3H6), 1,3-butadiene (C4H6) and methyl acrylate (C4H6O2). The obtained first order rate coefficient for the decomposition of MB is ktotal (1229-1427 K) = (3.08 � 1.11) � 1012exp(-(53.6 kcal mol-1 � 4.7)/RT) s-1, and for the formation of C2H4, the rate coefficient was found to be kethylene (1229-1427 K) = (7.92 � 2.72) � 109exp(-(47.6 kcal mol-1 � 4.5)/RT) s-1. Theoretical kinetic calculations were also performed for the unimolecular hydrogen transfer reactions using canonical variational transition state theory (CVT) with small-curvature tunneling (SCT) corrections. The temperature dependent rate coefficients for the overall reaction were computed in the temperature range of 500-2500 K, and were used to derive the Arrhenius expression: ktheorytotal (500-2500 K) = (9.05 � 1.91) � 1013exp(-(70.7 kcal mol-1 � 2.0)/RT) s-1. A reaction scheme containing 39 species and 66 elementary reactions was proposed to simulate the reactant and product concentrations over the temperature range of 1229-1427 K. The agreement between the experimental results and the model prediction for all the species is observed to be good. The decomposition of MB happens mostly via intramolecular hydrogen transfer than C-C bond and C-O bond fission. The majority of these intramolecular hydrogen transfer reactions are lower energy barrier reactions than the homolytic bond fission reactions. This journal is � The Royal Society of Chemistry.

Porous ZnO/Co3O4 heteronanostructures are successfully fabricated by a one-step solid state conversion of a novel [(Zn)x–(Co)7−x(BDC)(DHS)]·nH2O (x = 1, 3, 4, 6)] nano coordination polymers (NCPs). The precursor is prepared by one-pot wet chemical approach at room temperature without any surfactant using dihydroxy salophen ligand and 1,4-benzenedicarboxylic acid as the linkers in presence of zinc(II) acetate and cobalt(II) acetate in DMF solvent. Different weight ratios of the Zn/Co are fabricated in situ into the hetero-structures during the preparation of the NCPs to tune their physicochemical properties. The produced ZnO/Co3O4 nanostructure possesses relatively higher surface area (80–140 m2 g−1) and having significant N2 gas sorption capacity in comparison with reported materials. It is suggested that synergistic effect of each component, higher separation of electron and holes, high surface area and porous structure led to the promising visible light photocatalytic properties. The prepared mixed metal oxides show significant reusability in photocatalysis more than five times without losing their properties. Importantly, the mixed-metal NCPs could be applied as an effective route to generate not only binary oxide, but also ternary or quaternary oxide nanostructures with desired morphology and enhanced physicochemical properties.

Fabrication of superhydrophobic and oleophilic materials has attracted environment scientists due their application in oil spill clean-up. Herein, we report the preparation of superhydrophobic and oleophilic precipitated calcium carbonate sorbent via a simple and economical one-step synthetic approach using precipitated calcium carbonate as the substrate and palmitic acid as the surface modifying agent. The material is tested for its selectivity and effectiveness in the removal of spilled oil from both water and land surfaces. Test confirms the superhydrophobic character of the material with a static water contact angle of 166 ± 1°, whereas the oleophilic nature was validated from various oil uptake studies. In addition to being superhydrophobic and oleophilic, the sorbent material was found to be reusable for more than five times. Interestingly, the sorbent has high oil sorption selectivity, suitable buoyancy to float on water and possesses high oil sorption efficiencies (>99%).

Synthesis of indole based ethylenophanes has been achieved using direct N-arylation followed by McMurry coupling. All the ethylenophanes show antibacterial and antioxidant activity similar to that of commercially available drugs.

Selective photooxidation of different benzylic alcohols has been carried out in the presence of molecular oxygen and a catalytic amount of bromodimethylsulfonium bromide (BDMS) under visible light irradiation. The above method was found to be efficient for the oxidation of primary and secondary benzylic alcohols into their corresponding aldehydes and ketones with excellent product yield. Unlike other studies, the advantages of this study are the metal-free green protocol, utilization of a household compact fluorescent lamp (CFL) lamp as the visible light source, and the high selectivity of the reaction. A mechanistic study infers that the carbonyl compound obtained by the process possesses an oxygen atom which comes from molecular oxygen. From the study, we propose that the conversion of the benzylic alcohol to its corresponding aldehyde could be following a peroxy radical intermediate. The first-hand results revealed the photocatalytic potential of BDMS in general and its capability for selective alcohol oxidation, in particular.