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Remediation of organic pollutants from water using various techniques is a highly focused area in recent years, and visible light-aided heterogeneous photocatalysis is an emerging technique in this field.

The influence of lattice strain on metal and metal oxide catalysts has been widely investigated by DFT calculations. However, it is still hard to prove by experimental methods. In the present investigation, we have explained how the experimentally obtained strain values are reflected in the catalytic decomposition of hydrogen peroxide by using MnO2 decorated on TiO2 and ZnO catalysts. The lattice strain parameter values have been derived from X-ray diffraction patterns using the modified Williamson–Hall (W–H) method. Uniquely, we observed that compressive strain could significantly affect the TOF of the reaction, especially on the MnO2/TiO2 catalyst. Furthermore, the equilibrium constant calculated from the Langmuir–Hinshelwood (L–H) kinetic model shows that the MnO2/TiO2 catalyst has a stronger adsorption capacity than the MnO2/ZnO material. These results directly reflect the strength of the oxophilic sites and the lattice strain of the materials. A quantitative relationship has been established between lattice strain and catalytic activity.

Cyclohexadienone core 3,6-di-tert-butylcarbazole decorated triazole bridged dendrimers are synthesised up to the second generation using click chemistry via a convergent approach. The molar extinction coefficient and the intensity of the emission band increase with an increase in the dendrimer generation. The HOMO–LUMO energy level and the energy gap Eg obtained from photophysical and electrochemical parameters coincide with the results obtained from DFT calculations. The higher generation dendrimer 3 (G2) shows a higher Voc value and an increased efficiency of 9.01% when used as additive in DSSCs compared to the lower generation dendrimers 2 (G1) and 1 (G0) under 100 mW cm−2 illumination. Further, Nyquist plots obtained from electrochemical impedance measurements also show that the higher generation dendrimer G2 provides an increased number of charge transport pathways, which enhances interfacial electron transport and reduces the recombination dynamics.

The synthesis of rhodamine B decorated triazole bridged dendrimers with various aromatic cores is described by a convergent approach using click chemistry. The intensity of their absorption and emission bands increases upon increasing the dendritic generation. All the newly synthesized triazole bridged dendrimers exhibit antibacterial activity against human pathogens viz., B. subtilis, S. aureus, E. coli and K. pneumonia, which is also supported by molecular docking studies.

Graphene based visible light responsive photocatalysts have been actively used. Among various photocatalysts, bismuth ferrite (BiFeO3), with a suitable band gap, has gained more attention. In this work, BiFeO3 nanoparticles were prepared and grafted on graphene nanosheets (BiFeO3-g-GNS). The morphology, photocatalytic, structural, optical and magnetic properties of BiFeO3-g-GNS were investigated. The XRD analysis shows that the crystalline BiFeO3 nanoparticles have a rhombohedral crystal structure with the R3c space group. Well decorated graphene nanosheets (GNSs) with spherical perovskite type BiFeO3 nanoparticles (50–80 nm) are obtained, as confirmed by FESEM and HRTEM analysis. The Raman spectra and XPS spectra confirm the presence of different valence states (Fe3+, Bi3+) and chemical bonding (Fe–O, Bi–O) in BiFeO3. The M–H curves (at 10, 297 and 380 K) do not show any hysteresis after grafting on the GNSs. Moreover, the magnetic domain structure and the magnetization behavior of the BiFeO3 nanoparticles were discerned by MFM. The presence of GNSs reduces the band gap of BiFeO3 to 2.07 eV (BiFeO3-g-GNS) from 2.15 eV (pristine BiFeO3). Improved photoluminescence (PL) characteristics and a higher BET surface area have also been observed in the case of BiFeO3-g-GNS. The photocatalytic activities of pristine BiFeO3 and BiFeO3-g-GNS were tested by the degradation of cationic methylene blue (MB) and anionic methyl orange (MO) dyes. It has been observed that BiFeO3-g-GNS exhibits a higher photocatalytic activity toward MB (87%) and MO (35.9%) than the pristine BiFeO3 (57.9 and 4.1% respectively). Hence, the rate of photocatalytic degradation of the MB and MO dyes is significantly enhanced in the case of BiFeO3-g-GNS compared to pristine BiFeO3. The higher catalytic activity of BiFeO3-g-GNS is attributed to its lower band gap, higher absorption in the visible region and reduced recombination of photogenerated electron/hole pairs in the presence of GNS. Herein, we demonstrate that the photocatalytic activity of the BiFeO3 nanoparticles can be enhanced by grafting them on GNSs without influencing their magnetic and structural properties.

Triazole-bridged benzoheterazole dendrimers with a bisphenol/benzophenone core unit have been synthesized by click chemistry via a convergent approach. The optical properties of the benzoheterazole dendrimers and their modulation under the influence of the dendritic environment are investigated. All the synthesized benzoheterazole dendrimers show antioxidant properties comparable to those of the standards, viz: gallic acid and ascorbic acid, when tested by DPPH and ABTS radical scavenging methods. Higher generation dendrimers exhibit superior antioxidant activity than the lower generation dendrimers due to the presence of a higher number of 1,2,3-triazole and benzophenone units. The therapeutic efficacy of the benzoheterazole dendrimers in inhibiting the growth of the A549 cancer cell increases as the dendritic generation increases. Our study shows that the inhibition of cell proliferation is dose and time dependent. MTT assay, cell viability, cell counting, and clonogenic assay indicate that the benzoheterazole dendrimers inhibit the growth of cancer cells, as revealed by reactive oxygen species and mitochondrial membrane potential studies. Morphological changes of the cancer cell line after treatment with the benzoheterazole dendrimers showed the typical features of cell death cell shrinkage and reduction in the number of cancer cells.

1 : 1 and 2 : 2 oligomeric triazolophanes with 5-nitro isophthalate and triazolyl functionalities at the intraannular position have been synthesized by copper(I) catalyzed 1,3 dipolar cycloaddition of the corresponding propargylic esters with various phenyl substituted aliphatic azides under mild conditions through click methodology. The 1 : 1 oligomeric triazolophanes exhibit good target binding ability and better antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Salmonella typhi and Escherichia coli bacteria than the 2 : 2 oligomeric triazolophanes, supported by molecular docking studies, and triazolophanes T3, T4 and T5 show good larvicidal activity.

Triazole-branched BODIPY glycoconjugated dendrimers are synthesized by click chemistry in good yields via a convergent approach. All glycodendrimers show increase in the fluorescence intensity upon increasing the dendrimer generation. The cyclic voltammograms of dendrimers 1, 2 and 3 show a quasi-reversible behaviour. All the boron-dipyrrolomethene (BODIPY) dendrimers show antibacterial activity against both Gram positive and Gram negative bacteria viz., S. aureus and B. subtilis, and S. typhimurium and E. coli respectively and dendrimer 3 shows a better antibacterial activity than all the other synthesized dendrimers.

Temperature dependent rate coefficients for the gas phase reactions of Cl atoms with 4-hexen-3-one and 5-hexen-2-one were measured as a function of temperature (298–363 K) and pressure (500–760 Torr; N2 and O2) relative to 1,3-butadiene, isoprene and 1-pentene. Gas Chromatography (GC) coupled with a Flame Ionization Detector (FID) was used to measure the concentrations of the organics. The derived temperature dependent Arrhenius expressions are k1 = (2.82 ± 1.76) × 10−12 exp [(1556 ± 438)/T] cm3 molecule−1 s−1 and k2 = (4.6 ± 2.4) × 10−11 exp [(646 ± 171)/T] cm3 molecule−1 s−1. The corresponding room temperature rate coefficients are (5.55 ± 1.31) × 10−10 cm3 molecule−1 s−1 and (4.14 ± 1.25) × 10−10 cm3 molecule−1 s−1 for the reactions of Cl atoms with 4-hexen-3-one and 5-hexen-2-one respectively. To complement our experimental results, computational calculations were performed for the reactions of Cl atoms with 4-hexen-3-one, 5-hexen-2-one and 3-penten-2-one over the temperature range of 275–400 K using Canonical Variational Transition state theory (CVT) with Small Curvature Tunneling (SCT) in combination with the CCSD(T)/6-31+G(d,p)//MP2/6-311++G(d,p) level of theory. Atmospheric implications, reaction mechanism and feasibility of the title reactions are discussed in this manuscript.

Fluorene-cored dendrimers containing a triphenylamine chalcone unit at the periphery have been synthesized by divergent methodology using a click chemistry approach, and their photophysical and electrochemical properties have been investigated. All of the dendrimers exhibited quasireversible oxidation reduction signals in cyclic voltammetry. All of the dendrimers were used as additives in dye-sensitized solar cells (DSSCs), and the higher generation dendrimers exhibited better power conversion efficiency than the lower generation dendrimers in solar energy harvesting systems.

A novel CuO decorated Ag3AsO4/GO (CuO/Ag3AsO4/GO) ternary hybrid system is fabricated by an electrostatically-driven assembly method. The CuO nanostructure is obtained from a nano-coordination polymer by a facile solid-state transformation route. The prepared CuO/Ag3AsO4/GO hybrid shows a well-defined crystalline structure, where nanosized CuO particles (20 nm) are decorated on Ag3AsO4 spheres (150 nm) and further distributed on the GO sheets. The prepared CuO/Ag3AsO4/GO hybrid is characterized by PXRD, FT-IR, XPS, EDX, TEM, HRTEM, FESEM, UV-Vis DRS, BET and PL measurements. The CuO/Ag3AsO4/GO hybrid exhibits improvement in the visible light photodegradation of phenol compared to the CuO/Ag3AsO4 or Ag3AsO4/GO hybrid. The higher catalytic activity of the material can be ascribed to an increase in light harvesting, effective electron–hole separation and high surface area of the material. Furthermore, the CuO/Ag3AsO4/GO photocatalyst exhibits excellent photo-stability and reusability for more than five successive cycles signifying its potential applications in wastewater treatment. Interestingly, a Z-scheme type photocatalytic mechanism is proposed for the CuO/Ag3AsO4/GO hybrid under visible light.

A new class of triazoloferrocenyl conjugates (1, 2 and 3) was obtained by copper(I) catalyzed click chemistry, specifically the alkyne azide cycloaddition (CuAAC) of bis(β-hydroxyl)arylalkyneether with suitable ferrocenyl azides. The synthesized bis(β-hydroxyl)arylether linked ferrocenyl conjugates 1, 2 and 3 exhibit antifungal activity against fungal pathogens, viz. Candida albicans, Candida glabrata and Candida crusi, comparable to that of amphotericin B and also show excellent anticancer activity against MCF-7 cell lines.

A Zn/Bi mixed metal oxide (MMO) was synthesized by a simple co-precipitation method. Then Zn/Bi-MMO was hydrothermally treated with graphene oxide (GO) to obtain a Zn/Bi–RGO co-assembly. The XRD pattern confirms the formation of highly pure Zn/Bi–RGO nanoparticles. In the co-assembled Zn/Bi–RGO hybrid, GO had converted into RGO, which was evidenced by spectroscopy techniques, such as FT-IR, Raman, XPS, etc. UV-Vis DRS spectra infer that the prepared hybrid has significant absorption in the visible light region. The photocatalytic studies were conducted using 2-chlorophenol (2-CP) and 2,4-dichlorophenol (2,4-DCP) and the hybrid offered almost complete degradation of pollutants as compared to pure Zn/Bi-MMO. The enhanced photocatalytic activity of Zn/Bi–RGO hybrids is due to the homogeneous distribution of Zn/Bi-MMO over RGO sheets as well as electron transportation efficacy of the RGO sheets. The mechanism of catalysis is expected to have two key events; namely a charge transfer mechanism, which initiates the reaction, followed by an electron–hole aided radical mechanism.

Herein, we report a strategic design of dual temperature and pH responsive polymer integrated magnetic nanohybrids comprising of smart block copolymers and mixed ferrite nanoparticles (MFNPs) for efficient anti-cancer drug delivery and magnetic resonance imaging (MRI). Citrate stabilized mixed ferrite nanoparticles (CA-MFNPs) were intelligently modified with the dual responsive polyethyleneimine (PEI) cross-linked Pluronic F127 copolymer via the EDC/NHS method. In order to accomplish cancer targeting and imaging capability, both the folic acid (FA) and rhodamine isothiocyanate (RITC) were tethered to the nanoparticles via intricate chemical approaches. These FA targeted nanohybrids were further entrapped with doxorubicin (DOX) and their release pattern was investigated. These DOX loaded FA targeted nanoparticles (DOX–FA–Poly-MFNPs) demonstrated high drug payload and encapsulation efficiency i.e. 4.6% and 92.0%, respectively. It is shown that at the lower pH/higher temperature i.e. acidic pH (5.0) and at body temperature (37 °C), the DOX–FA–Poly-MFNPs exhibited enhanced release of DOX (drug release value ∼53%) while retaining their stealthy structure under physiological conditions (drug release value ∼12%), exhibiting an apparent thermo/pH controlled drug release pattern. The folic acid receptor (FAR) specific endocytosis to cancer cells (human cervix adenocarcinoma i.e. HeLa) in comparison to normal immortalized keratinocytes (HaCaT) cells were demonstrated via fluorescence microscopy and magnetic resonance imaging (MRI). Furthermore, these DOX–FA–Poly-MFNPs displayed effective therapeutic activity evaluated by a cytotoxicity assay and cell cycle analysis in HeLa cells. Therefore, these dual responsive mixed ferrite nanoparticles may serve as promising theranostic agents for in vivo cancer therapy.

Triazole bridged novel donor–acceptor dendrimers with triphenylamine as the core and benzoheterazole as the surface unit have been synthesized by click chemistry via a convergent approach. All the dendrimers exhibited excellent optical and electrochemical properties, as supported by DFT calculations. Lower generation dendrimers exhibit better current-generating capacity and also show better power conversion efficiency than higher generation dendrimers when used as additives in dye-sensitized solar cells.

The fabrication of a novel porous Ag deposited SnO2/NiO (Ag/SnO2/NiO) heteronanostructure for the photoreduction of toxic aqueous Cr(VI) to non-toxic Cr(III) is reported. The material is prepared by depositing metallic Ag nanoparticles into the SnO2/NiO heteronanostructure by the reduction of Ag+ under UV irradiation. The SnO2/NiO heteronanostructure is obtained by a facile solid-state transformation of the novel nanocoordination polymer (NCP). The prepared Ag/SnO2/NiO is characterized by different techniques such as PXRD, XPS, EDX, FESEM, TEM, HRTEM, BET, UV-Vis DRS and PL measurements. The PXRD and XPS studies confirm the formation of a Sn(IV) state of SnO2 in the heterostructure. TEM images reveal the spherical morphology of Ag nanoparticles with an average particle size of 15 nm, and hexagonal shaped SnO2 and NiO with an average particle size of 10 and 5 nm in Ag/SnO2/NiO, respectively. The incorporation of Ag enhances visible light absorption and higher electron–hole separation of Ag/SnO2/NiO by Surface Plasmon Resonance (SPR). Besides, the material exhibits a high surface area and porous nature, which facilitates the effective photocatalytic reduction of toxic aqueous Cr(VI) to non-toxic Cr(III) under visible light. Furthermore, the photocatalytic reduction of Cr(VI) is optimized under different conditions. The photostability of Ag/SnO2/NiO is tested up to five successive runs indicating its promising applications for wastewater treatment. Finally, a photocatalytic mechanism is proposed for the reduction of aqueous Cr(VI) over Ag/SnO2/NiO under visible light.

1 : 1 and 2 : 2 oligomeric piperazinophanes with an intraannular ester functionality have been synthesized via Mannich reaction of various aromatic esters with piperazine by a one-pot reaction under benign conditions through the multicomponent reaction methodology. The newly synthesized piperazinophanes were characterized using spectral and analytical methods. The ester based 1 : 1 oligomeric piperazinophanes exhibit good target binding ability in molecular docking studies and also show better antibacterial activity against Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus and Streptococcus pyogenes bacteria than the 2 : 2 oligomeric piperazinophanes.

Triazole-based novel dendrimers with ferrocenyl surface groups have been achieved through click chemistry, both by divergent and convergent approaches. The presence of more ferrocenyl and triazolyl units in dendrimers 1–4 alters the current potential curve in the voltammogram and also the absorption coefficient in the UV-vis spectrum.

Dendrimers with benzothiazole–benzoxazole surface groups and electron transporting triazole as bridging units and diphenyl sulfone as core unit were synthesized successfully by Cu(I)-catalysed Huisgen ‘click reaction’ using a convergent approach. All the dendrimers exhibit excellent optical and electrochemical properties. Higher-generation dendrimers exhibit better current generating capacity and show better power conversion efficiency than lower-generation dendrimers when used as additives in dye-sensitized solar cells.

Dendritic architectures with 1,2,3-triazole as the building unit and dimethyl isophthalate as the surface group are synthesized through a convergent approach employing click chemistry and tested for their application in dye-sensitized solar cells (DSSCs). The studies revealed that the presence of triazole and isophthalate groups in dendritic structures significantly altered the absorption, electrochemical and DSSC behaviors. In DSSCs, the dendritic structures exhibited higher Voc values and higher power conversion efficiency (η) in the I−/I3− redox couple under simulated conditions at 40 mW cm−2.