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Leishmaniasis is a neglected tropical disease, and there is an emerging need for the development of effective drugs to treat it. To identify novel compounds with antileishmanial properties, a novel series of functionalized spiro[indoline-3,2′-pyrrolidin]-2-one/spiro[indoline-3,3′-pyrrolizin]-2-one 23a–f, 24a–f, and 25a–g were prepared from natural-product-inspired pharmaceutically privileged bioactive sub-structures, i.e., isatins 20a–h, various substituted chalcones 21a–f, and 22a–c amino acids, via 1,3-dipolar cycloaddition reactions in MeOH at 80 °C using a microwave-assisted approach. Compared to traditional methods, microwave-assisted synthesis produces higher yields and better quality, and it takes less time. We report here the in vitro antileishmanial activity against Leishmania donovani and SAR studies. The analogues 24a, 24e, 24f, and 25d were found to be the most active compounds of the series and showed IC50 values of 2.43 µM, 0.96 µM, 1.62 µM, and 3.55 µM, respectively, compared to the standard reference drug Amphotericin B (IC50 = 0.060 µM). All compounds were assessed for Leishmania DNA topoisomerase type IB inhibition activity using the standard drug Camptothecin, and 24a, 24e, 24f, and 25d showed potential results. In order to further validate the experimental results and gain a deeper understanding of the binding manner of such compounds, molecular docking studies were also performed. The stereochemistry of the novel functionalized spirooxindole derivatives was confirmed by single-crystal X-ray crystallography studies.

Herein, we present a scalable and economic synthesis of covalent organic microspheres, a highly cross-linked microspherical polymer, through a single step process. The as-synthesized imine-linked m...

Herein, we report for the first time, an eco-compatible hydrothermal route for the synthesis of carbon enriched mesoporous material (CuO NFs@MP) using fruit waste (Pulp) obtained from Citrus limetta’s (Mausambi) decorated irregular shaped CuO nanoflakes (NFs). The CuO NFs@MP nanocomposite was fully characterized through several spectroscopic-cum-analytical techniques such as TEM and XPS, which further confirmed the presence of CuO NFs. CuO NFs@MP could serve as an excellent catalyst for N-Arylation reaction and also paves promising peroxidase mimic activity. The preliminary results indicated that CuO NFs@MP shows the catalytic advantage of higher yields, shorter reaction time and greener conditions. Simultaneously, the oxidation of colorless TMB with H2O2 into blue-green colored ox-TMB was also observed in 60 s with CuO NFs@MP. The present nanocomposite is easy to synthesize, economical, retrievable and a reusable catalyst for synthesizing a varied range of N-Arylated products and could also mimic peroxidase without significant loss of activity. Keywords: Fruit waste (Pulp), Copper oxide Nanoflakes, Porous Carbon, N-Arylation, Peroxidase mimic activity

A new micro-spherical covalent organic polymer was synthesized by imine linkage between two triazine-cored precursors under solvothermal conditions. This COP attains spherical morphology and promising solid-state properties along with reversible chromogenic response toward the sensitive detection of the noxious HCl gas. The as-synthesized COP material can then serve as the first microsphere-based chromogenic solid-state gas sensor.

In the present study, we have designed and synthesized indole derivatives by coalescing the indole nucleus with chromene carbonitrile and dihydropyridine nucleus. Two compounds 5c and 6d were selected from series I and II after sequential combinatorial library generation, docking, absorption, distribution, metabolism and excretion (ADME) filtering, anti-proliferative activity, cytotoxicity, and ER-α competitor assay kit by utilizing estrogen receptor-α (ER-α) dominant T47D BC cells line and PBMCs (Peripheral Blood Mononuclear Cells). Cell imaging experiment suggested that both the compounds successfully cross cellular biomembrane and accumulate in nuclear, cytoplasmic and plasma membrane region. Semiquantitative RT-PCR and Western blotting experiments further supported that both compounds reduced the expression of mRNA and receptor protein of ER-α, thereby preventing downstream transactivation and signaling pathway in T47D cells line. Current findings imply that 5c and 6d represent novel ER-α antagonists and may be used in the development of chemotherapy for the management of BC.

This review focuses on the recent growth in the photo triggered molecular receptors for heavy metal ions. The photochromic unit in such molecular receptors performs as a trigger unit to allow control over a range of the properties through an external stimulus. This review opens up with the new opportunities for the development of host molecular motifs for heavy metal ion sensing applications. The photochromic switches based on a chemical structure like spiropyran, chromenes and spirooxazines tagged with appropriate chromogenic or fluorogenic unit reported till date have been summarized and categorized by the selectivity of metal ion to achieve the suitable optical response. The review has relevance for designing new photoreversible switches with the interesting optical response for environmentally important heavy metal ions.

A photoresponsive spiropyran derivative was synthesized and evaluated for redox and light-responsive behavior. The response of the spiropyran derivative was also investigated towards metal ions using techniques like UV-vis, digital colorimetry, and cyclic voltammetry (CV). Photochromic spiropyran displayed redox responsive behavior, which was influenced by UV and Visible lights. Redox responsive spiropyran selectively interacted with Fe3+ ions, which was exploited to demonstrate alteration in the cyclic voltammetric (CV) signal in the Fe3+ ion complex. The probe was further used as a light-controlled reversible tool for the detection of Fe3+ ions. CV studies under light irradiation indicated that the visible light (450 nm and 532 nm) exposure led to a change in the current (Ip,c & Ip,a) for the probe and probe-Fe3+ complex. However, the reversibility was witnessed in the voltammogram when solutions were exposed to 450 nm visible light. Digital colorimetry in solution and on a paper-based device aided by a smartphone was successfully used to perceive ferric ions with the help of spiropyran. The reuse of the probe on a paper-based device was demonstrated in water through digital mode assisted by a smartphone with the aid of 450 nm light.

A merocyanine salt form of a substituted spiropyran was synthesized and evaluated for stimuli-responsive properties. The HSO4− induced H-aggregation of the merocyanine salt was used as a strategy for detection in pure water. The anion induced aggregation was controlled by light, which converted the open merocyanine form into the closed spiropyran form. The formation of the closed form released the hydrogen sulfate ion. The DLS and TEM analyses were used to investigate the aggregation and disaggregation of the merocyanine salt form of a spiropyran. Therefore, the study establishes the first example of reversible, highly selective and nanomolar level response towards HSO4− ion in water.

An anthracene-oxazine conjugate was synthesized by hybridizing the fluorescent anthracene unit with the photochromic nitrosubstituted oxazine. The structure of the conjugate was established by using IR, NMR, HR-MS and single crystal X-ray crystallography. The anthracene-oxazine conjugate was evaluated for affinity towards different anions in aqueous medium and selectivity towards cyanide ion was observed through development of color visible to the naked eye as well as through changes in fluorescence signal. An excellent value of 58 nm limit of detection value was obtained, which indicated an excellent sensitivity of the probe towards cyanide ion. The probe displayed fluorescence quenching via intramolecular energy transfer from the hybridized anthracene unit to the parent oxazine photochrome upon addition of the cyanide ions in aqueous medium. DFT calculations were performed to support the experimental data.

A triazine-cored covalent organic polymer (COP) was designed and synthesized via amine linkages under ambient conditions. The novel architecture of the COP was fully characterized via spectroscopic and analytical techniques. The present COP demonstrates a quick, portable and reversible chromogenic response towards noxious HCl vapours.

Anthracene fluorophore and an oxazine chromophore get coupled within the same molecular configuration to produce a molecular machine based receptor 1. On treatment with TFA, the oxazine closed form gets open in conjugation with the 1, 3, 3-Trimethylindoline species. This molecular change produces a bathochromic shift of 140nm directly from UV to Visible region in association with intense pink color. This molecule can be used as molecular ink to print a different colored decoration on paper. Upon addition with TEA, the colored open forms of the receptor revert to its original colorless form to rub the printed impression. Thus, the simple paper can be used for multiple times to achieve the write-read-erase strategy. This photoswitchable molecular motif can evolve many opportunities in the industry for printing purpose and huge paper consumption.

A nitrophenyl azo substituted spiropyran was synthesized and characterized spectroscopically. The substituted spiropyran derivative was evaluated for affinity towards different anions in MeCN:water (10 mM HEPES buffer) at different pH. The spiropyran derivative selectively detected cyanide ions by displaying blue or purple color visible to the naked eye and through spectral changes. The 1 H NMR spectra was used to confirm the binding of cyanide ion to the receptor. The nitrophenyl azo group amplified the observed change in color triggered by cyanide binding to the spiropyran derivative enabling high sensitivity.Theoretical methods were used to investigate the experimental observation at the molecular level.

Photochromic naphthopyran derivatives were synthesised for anion recognition applications. The crystal structure, experimental and theoretical investigation of photochromic and anion sensing properties of a simple naphthopyran derivative were investigated. The naphthopyran derivative displayed good fatigue resistance and selective sensing response towards cyanide ions. The mechanism of complex formation was suggested based on NMR studies. Theoretical calculations were performed to understand the experimental results. An excellent correlation between the theoretical and experimental data was observed.

This work reports a novel solution-based method to trigger the growth of diatoms for enhanced biomass production, which can efficiently stimulate their applications in nutraceuticals, aquaculture and wastewater remediation. The optimization for the growth of three marine diatoms species was performed using inductively coupled plasma (ICP) synthesized nanosilica which can be a cost-effective and productive method for biomass production. The exponential growth phase was achieved in 14 days with high biomass productivity compared to F/2-Si Media [Chaetoceros sp. (125 ± 3 & 750 ± 3 mgL−1day−1); Skeletonema sp., (185.3 ± 2.63 & 562.5 ± 3.96 mgL−1day−1) and Thalassiosira sp. (312.5 ± 2.51 & 433.5 ± 1.80 mgL−1day−1)] along with a sharp rise of 50–100 fold increment in pigmentation. This work opens up an avenue with novel insights to trigger the growth of diatoms on large scale leading to their better exploitation towards biotechnological applications.

A novel curcumin based molecular probe L1 was synthesized using 2-aminothiazole through covalent linkage. The structure of the probe L1 was characterized by UV–Vis, Fluorescence, SEM, PXRD and other related spectroscopic techniques. The molecular probe L1 was screened over assorted metal ion and selectivity was observed with Cu2+ and Hg2+ ion through the change of color in aqueous medium which was confirmed by UV or fluorescence signal and also supported by SEM and PXRD results. An unusual value of LOD with Cu2+ and Hg2+ ion was calculated to be 2.0 μM and 1.2 μM, respectively, which confirmed the selectivity of L1. The quenching in fluorescence spectrum was observed only with Cu2+ and Hg2+ ion, due to the loss of energy. The complex formation between L1 and Cu2+/Hg2+ ions were further studied by density functional theory using B3LYP/6–31(G) method to support the experimental results. Time-dependent-DFT studies were performed with LANL2DZ basis set to study the accurate complex mechanism which indicated a large HOMO-LUMO gap with Hg2+ ions.

This paper experimentally investigates the thermal management and performance improvement of solar PV panel with the help of a Phase Change Material (PCM). The two solar PV panels of 30 Watts nominal power and same configuration were selected for the experiments. The candle making wax (CMW) was chosen to be the PCM. One PV panel named as PV1, which was tested without any physical modification and another panel (named as PV2) was tested after integrating with the PCM at the back side. The solar PV panels were experimented in a solar day from 6 a.m. to 5 p.m. Their panel surface temperature and the electrical efficiencies were observed and compared. The results proved that the PCM reduced the panel surface temperature by 24.24% and decreased the maximum panel temperature by 17.57%. In addition to this, the hourly efficiency of the panel was enhanced by 4.43% and daily efficiency was boosted by 6.34% with the aid of PCM.

Thermal energy storage becomes a greater challenge in thermal conversion systems such as solar thermal systems. The energy demand and supply may not be matched at the most point of time, hence requires efficient thermal energy storage. Candle Making Wax (CMW) is one among the potential material to store energy by means of changing its phase. Still, they are suffering with poor thermal conductivity. This paper addresses this problem by diffusing a suitable nanoparticle in CMW. Nano-TiO2 particles have been used as enhancer in CMW in different proportions viz., 0 vol.%, 0.5 vol.%, 1.0 vol.%, 1.5 vol.% and 2.0 vol.%. These five samples were inspected using Fourier Transform Infrared Spectrometer (FT-IR) to verify their chemical stability. Thermal conductivity of all the samples were initially calculated using different analytical models and later, they were experimentally determined with the help of thermal properties analyzer. The results proved that the thermal conductivity can be improved substantially by dissolving the nano-TiO2 in CMW. Thermal conductivity escalates with the increased vol.% of nanoparticles. However, values predicted through the analytical models showed the linear improvement, whereas the experimental values were not exactly linear and their slope becomes less at the higher vol.% of nanoparticles. It was observed that the solid state thermal conductivity was more compared to their liquid state, Also, it was noticed that the experimentally measured values were relatively higher than the values obtained through the analytical models and variation was high at higher vol.% of nanoparticles.

Herein, we present the first report on TiO2 NPs based hybrid nano-reactor designed and synthesized via N-(2-amino ethyl)-3-amino propyl trimethoxy silane (AAPTMS) functionalization of graphene oxide (GO). The as-synthesized nano-reactor was characterized by means of several analytical-cum-spectroscopic techniques that support the successful attempt for the synthesis of TiO2@AAPTMS-rGO. Further, the present catalyst was evaluated for its catalytic performance towards an expedient access to biologically relevant synthesis of 2,4,5-triaryl imidazoles. The functional sites of TiO2@AAPTMS-rGO direct the catalysis from the reactant to product with high atom economy, shorter reaction time and excellent yields. Moreover, the present catalyst TiO2@AAPTMS-rGO shows promising reusability for several catalytic cycles. It also provides a robust approach for 2,4,5-triaryl imidazoles with improved performance and without significant loss in catalytic activity. Further, this catalyst can be upgraded for other organic transformations leading to numerous pharmaceuticals and environment benefits.

A triazine based covalent organic polymer (CC-TAPT-COP) was designed and synthesized via nucleophilic substitution reaction between 1,3,5-tris-(p-aminophenyl) triazine and cyanuric chloride under refluxing conditions with bottom-up approach. The structural and morphological properties of CC-TAPT-COP were well characterized by various spectroscopic and analytical techniques. The CC-TAPT-COP appeared as an irregular block morphology (SEM) and possesses remarkable thermal stability. The physical properties such as insolubility, chemical and thermal stability of CC-TAPT-COP provide a sustainable alternative to classical metal-assisted and homogeneous catalysts. In this report, we have explored CC-TAPT-COP as a heterogeneous catalyst for expedient access to the substituted quinazoline, a family of N-containing biopharmaceutical active heterocyclic compounds, at ambient conditions. Moreover, the present work not only supports COPs for their synthesis, but also paves an opportunity for catalytic applications as heterogeneous media.

An ibuprofen based molecular receptor R1 (N-[2-[(2-Hydroxy-benzylidene)-amino]-ethyl]-2-(4-isobutyl-phenyl)-propionamide) was developed for the detection of Cu2+ ion in aqueous medium by absorbance and fluorescence techniques. Binding constants (4.89–5.67 × 103 M−1) and detection limits (1.71–2.12 μM) showed significant sensing ability. SEM and PXRD techniques were employed to establish the complex formation between R1 and Cu2+ ion and also showed promising behaviour of nanomaterial. The competitive binding experiments showed the selectivity of Cu2+ ion in presence of other metal ions in aquoues medium. The reversibility studies for chemosensor R1 was investigated and EDTA used as restoring agent. The strong chelation through –N and –O atoms of receptor R1 enhance the change in color triggered selectively by Cu2+ ion and detected by colorimetric methods. The theoretical calculations were employed in order to confirm the experimental observations in the molecular frames.