Cyclohepta[b]indole derivatives constitute a prominent class of indole-annulated medium-sized ring systems that occur in diverse bioactive natural products and pharmaceutically relevant scaffolds. Their enantioselective construction, however, remains intrinsically challenging owing to conformational flexibility, transannular interactions, and unfavorable thermodynamic/entropic features associated with seven-membered ring formation. This review summarizes progress in emerging asymmetric methodologies that deliver chiral cyclohepta[b]indole frameworks, by highlighting advances in catalyst design, reaction efficiency, and stereocontrol, alongside mechanistic insights that rationalize selectivity trends and guide future development.

Enantioenriched indole frameworks constitute the structural core of a wide array of biologically active natural products and therapeutic agents; as such, their synthesis has emerged as a central and enduring objective in organic synthesis. In this regard, suitably substituted indolylmethanols have emerged as versatile precursors to a series of catalytic asymmetric transformations to construct complex indole-based architectures. This article provides a concise overview of the fundamental chemistry of n-indolylmethanols, with a specific emphasis on their role as key substrates in enantioselective cycloadditions catalyzed by chiral phosphoric acids.

To protect exorbitant assets from micro-cracking, damage, and fatigue (due to prolonged use and weathering conditions), a self-healing coating is one of the revolutionary choices. Herein, nickel-doped biochar-based highperformance filler is introduced into the vitrimer matrix to develop a highly protective coating material. A generous strategy was introduced to modify the biochar with nickel doping to enhance the self-healing efficiency with enhanced microwave absorption as well as the mechanical properties. The developed composites display excellent self-healing efficiency when irradiated with microwave via a transesterification exchange mechanism and a rapid relaxation time with decomposition temperature approximately 310 degrees C. The composites also demonstrate consistent thermo-mechanical properties (with 24.2 GPa storage modulus and 18.8 MPa stress at 1.9 strain%) along with noticeable stress relaxation ability with 39 kJ/mol activation energy, indicating a fast dynamic bond exchange reaction in the network. The composites exhibit amazing shape-memory and self-adhesive properties in the presence of microwave radiation as stimuli. Their strong hydrophobic behavior, comprising selfhealing properties, positions these smart materials as ideal candidates for protective marine coatings, offering resistance against harsh environmental conditions.

A simple method for constructing unsymmetrical 2-nitrobiaryls has been developed between substituted 1,4-dithiine-2-carbaldehyde and nitroolefins under metal-free conditions. To gain the advantage of the HOMO-raising effect of temporary substitutions on in situ generated dienamine intermediate, the present protocol established [4+2] benzannulation of 1,4-dithiane-tethered enals with nitroolefin. Further, easy unmasking of 1,4-dithiine units results in a benzannulation product like that of unsubstituted enals, which are difficult to access. Several 2-nitrobiaryls have been accessed with moderate to good yields and with promising synthetic applications.

A two-pot method has been developed to access indolizino[8,7-b]indole derivatives through Lewis acid-mediated regioselective C5-cyclization of 3-acylpyrrole prepared from the feedstock materials. The overall reaction proceeds through amine-catalyzed direct aldol reaction/Paal-Knorr reaction/oxidation between succinaldehyde, aromatic aldehyde, and tryptamine in a sequential multicomponent fashion for N-alkyl pyrrole followed by dearomative cyclization. A series of substituted indolizino[8,7-b]indoles have been prepared with good yields and excellent regioselectivity.

2,2-Disubstituted indolin-3-ones, which are essential components in many manufactured chemicals, dyes, and naturally occurring bioactive alkaloids, have emerged as exciting synthetic targets. Much attention has been paid to accessing these units, particularly in an asymmetric fashion, during the last decade. In this review article, we discuss the current state of available methods with existing mechanistic pathways for accessing chiral indolin-3-one derivatives under various catalytic systems. This overall presentation of asymmetric catalytic protocols to access 2,2-disubstituted or fused indolin-3-ones with an aza-quaternary centre is categorized based on the reaction modes of 2-substituted-3H-indole-3-one derivatives or other similar protocols.

Construction of a chiral methanamine unit at the C3 position of pyrrole is highly desirable; nevertheless, it remains challenging due to its intrinsic electronic properties. Herein, we present an operationally straightforward and direct asymmetric approach for accessing alpha-(3-pyrrolyl)methanamines under benign organocatalytic conditions for the first time. The one-pot transformation proceeds smoothly through an amine-catalyzed direct Mannich reaction of succinaldehyde with various endo-cyclic imines, followed by a Paal-Knorr cyclization with a primary amine. Several N-H/alkyl/Ar alpha-(3-pyrrolyl)methanamines with an aza-tetrasubstituted center have been synthesized with good yields and excellent enantioselectivity.

Due to its structural complexity and intrinsic sensitivity of bridged aminal junction, 2,6-diazabicyclo[2.2.2]octane (2,6-DABCO) has remained a highly desirable target in synthetic chemistry. However, the asymmetric access to this unit is still insufficient and hampered by the need for meticulously created functionalities for intricate double aza-cyclizations. Herein, we have developed a novel enantio- and diastereoselective protocol to access polycyclic chiral 2,6-DABCOs under metal-free conditions. This domino process involves the amine-catalyzed [4+2] annulation between glutaraldehyde and 2-arylindol-3-ones, followed by an acid-mediated Pictet-Spengler reaction/intramolecular aza-cyclization cascade sequence with tryptamine by trapping of in situ generated 3-oxindolium ion intermediate for the first time. Overall, 2,6-DABCOs fused with medicinally relevant scaffolds were isolated with good yield and excellent stereoselectivity by constructing five new bonds and four stereocenters in a one-pot operation.

In the present work, one-step, mass-scale productive solid state reaction method has been employed for the preparation of gadolinium (Gd) doped ZnO (GZOx: x = 0, 2, 4, 6, 8 wt%) nanostructures. The prepared GZOx samples have been studies their structural, morphological, elemental diffusion profile and optical properties using P-XRD, FE-SEM, EDS, FTIR, and photoluminescence (PL) spectroscopy. The powder X-ray diffractometer (P-XRD) results clearly indicate strong and sharp diffraction peaks with broadening that confirms the formation of hexagonal nanocrystalline structure of ZnO and Gd doped ZnO. The hexagonal morphology formation of the grains after doping of Gd contents into the ZnO nanostructures system is seen from the FE-SEM micrographs and the sizes of the grains are found to close to the results obtained from XRD patterns. The presence of Gd contents in ZnO matrix confirms its doping by EDS spectrum of 4 wt% Gd doped ZnO nanostructures. Fourier transform infrared (FTIR) results confirm the presence of functional groups and chemical bonding of ZnO at room temperature. Investigation of optical emission is interesting and the PL spectra reveal two emission peaks, one in UV-region located in the range of ∼385 to 395 nm and other is defects related emission centred at ∼450, ∼468, ∼503 and ∼562 nm in visible region for all the samples. The enhanced PL intensity is observed in the higher doped Gd contents in ZnO nanostructures and can be attributed to the presence of Gd ions into ZnO lattice. The detailed structural and luminescence analysis has been carried out and correlated. The study of structural and optical properties GZOx samples suggest the luminescent optoelectronic applications.

This paper presents the outcome of medicinal plant-derived synthesis of nanomaterial. The results in the present study provide a simple, novel, sustainable, and economically noble process for the synthesis of palladium nanoparticles using leaf extract Aegle marmelos (A. marmelos). Fourier transformed infrared spectroscopy (FTIR) was used to verify the surface layer of synthesized palladium (ALE@Pd) nanoparticles (NPs) enriched with several kinds of phytochemicals. Transmission electron microscopy (TEM) revealed that the synthesized NPs possess a ball shape and the average diameter was 4.31 +/- 1.89 nm. The synthesized NPs possess stability confirmed by UV-visible (UV-Vis) spectrophotometry. The face-centered cubic (FCC) crystal structure of the fabricated nanoparticles was confirmed by powder X-ray diffraction (PXRD). Fabricated ALE@Pd NPs are subjected to further testing for their cytotoxicity in HeLa cell lines, as well as for a comparative study of antioxidant activity between the A. marmelos leaves and prepared ALE@Pd NPs. The anti-carcinogenic activity and cell imaging in HeLa cells were tested, and the minimal inhibition concentration (MIC or IC50) has been determined and found to be around 46 mu g/mL for HeLa cell lines. Fabricated palladium nanoparticles derived from A. marmelos have the potential to be employed as an environmentally friendly and cost-effective anticancer agent. Furthermore, synthesized ALE@Pd NPs possess higher antioxidant activity than A. marmelos leaves extract (ALE) due to the increased phenolic content connected to the surface of produced palladium NPs as a capping agent. The minimal inhibition concentration of synthesized ALE@Pd NPs was found to be similar to 5 mu g/mL.

The ion-exchange method removed Ni(II) from synthetic wastewater using biomass obtained as agricultural waste. Sugarcane bagasse (SB) works as an alternate replacement in place of activated charcoal to withdraw Ni(II) from an aqueous solution. Diverse parameters determined the SB's adsorption ability, including contact time, metal ion concentration, pH, and adsorbent dose, at four distinct temperatures (20°C, 30°C, 40°C, and 50°C). Characterization of the SB adsorbent involved miscellaneous techniques, such as for morphological analysis: field emission scanning electron microscopy was used, for structural analysis: Fourier transform infrared spectroscopy was used, and Brunauer–Emmett–Teller was used for the determination of surface area respectively. The biosorption process of the Ni(II) on the SB was investigated by employing two adsorption isotherms, Langmuir and Freundlich adsorption isotherms. Among these two adsorption isotherms, the Langmuir model is the best-fitted model with regression coefficient values (Adj. R2) of more than 0.98. The kinetic study of the biosorption process of the Ni(II) on the SB was also evaluated and found to follow second-order kinetics.

An operationally simple catalyst-free protocol for the direct regiospecific synthesis of C3-arylated/alkenylated pyrroles has been developed. The enamine-intermediate, in situ generated from succinaldehyde and a primary amine, was trapped with activated carbonyls before the Paal-Knorr reaction in a direct multicomponent 'just-mix' protocol to furnish pyrroles in good yields. Several C3-substituted N -alkylpyrroles have been prepared under open-flask conditions, avoiding protection-deprotection chemistry.

The present paper reports a biogenic synthesis of palladium nanoparticles (PdNPs) involving Cannabis sativa leaf extract. The physicochemical characterisations of biogenic synthesised PdNPs were carried out to determine size, shape, morphology, atomic composition, and crystal structure via different techniques involving Ultraviolet-visible (UV-vis), Fourier transform infrared (FT-IR), Field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), and X-ray diffraction (XRD). The standard particle size of the synthesized PdNPs was found to be 3.49 +/- 0.5 nm from the TEM analysis, while XRD analysis showed a crystal size of 4.6 nm with a face-centred-cubic (fcc) structure. FT-IR study of the green synthesis confirmed the presence of phytochemicals which act as reducing and stabilising agents. The synthesised biogenic PdNPs were subjected to antimicrobial analysis for isolated strains of multi-drug resistant (MDR) Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus and Salmonella abony where minimum inhibitory concentration (MIC) was found in the range of 52.04-68.3 mu g/mL. Moreover, for the cytotoxic effects of biogenic PdNPs, A549 lung cell lines were used, and the half-maximal inhibitory concentration (IC50) value was evaluated as 22.17 mu g/mL. The present investigation suggests the possible role of C. sativa extract capped PdNPs in the clinical management of lung cancer cells and MDR pathogens.

A simple and straightforward method is developed for the enantioselective synthesis of indol-3-yl-piperidine. The reaction proceeds through a proline-catalyzed direct Mannich reaction between glutaraldehyde and C3-indolyl-imines, followed by intramolecular reductive cyclization as an overall [4+2] annulation in one-pot fashion. A series of indol-3-yl-piperidine have been accessed with good yields up to 71 % and high enantioselectivity up to >99 % ee.

The kinetic investigation of Hg(II)-promoted reaction between [Fe(CN)(6)](4-) and 2,2'-bipyridine (Bipy) has been performed in anionic sodium dodecyl sulfate (SDS) micellar medium by recording the surge in absorbance at 400 nm, corresponding to ultimate reaction product [Fe(CN)(4)Bipy](2-) using UV-visible spectrophotometer. Pseudo-first-order condition has been used to examine the progress of reaction as a function of temperature, [Fe(CN)(6)(4)(-)], ionic strength, [SDS], pH, [Hg2+], and [Bipy] by changing one parameter at a time. The results exhibit that [Hg2+], [SDS], and pH are the decisive parameter showing maximum reaction rate at 1.5 x 10 -4 mol dm(-3), 6.0 x 10(-3) mol dm(-3), and 3.8, respectively. [Fe(CN)(6)](4-) does not show any appreciable effect on the critical micellar concentration (CMC) of SDS as the polar head of SDS and [Fe(CN)(6)](4-) both are negatively charged. Variable order kinetics was observed for [Fe(CN)(6)](4-) and Bipy in their examined concentration range. The reverse response observed in the reaction rate with [KNO3] shows a negative salt effect. The K+ provided by K-4[Fe(CN)(6)] and KNO3 decreases the repulsion between the negatively charged heads of the surfactant molecules thereby decreasing the CMC of SDS. The negative value for the entropy of activation also supports the interchange dissociative (I-d) mechanism recommended by us.

A straightforward method has been developed to synthesize2-aryl-3-(2-aminoaryl)quinoxalines from 2-arylindoles and 1,2-diaminoarenes under mild electrochemicalconditions. The reaction proceeds through in situ generations of 2-arylindole-3-onesunder electrochemical oxidative dearomatization of 2-arylindoles,followed by a ring opening-cyclization sequence with 1,2-diaminoarenes.A series of 2-aryl-3-(2-aminoaryl) quinoxalines have been preparedwith moderate to good yields (up to 75%).

A simple and straightforward method is developed for the enantioselective synthesis of indol‐3‐yl‐piperidine. The reaction proceeds through a proline‐catalyzed direct Mannich reaction between glutaraldehyde and C3‐indolyl‐imines, followed by intramolecular reductive cyclization as an overall [4+2] annulation in one‐pot fashion. A series of indol‐3‐yl‐piperidine have been accessed with good yields (up to 71%) and high enantioselectivity (up to >99% ee).

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

This study involves the single-step, mass-scale productive synthesis, photoconduction, and luminescence characteristics of pure and cerium rare-earth-ion-doped ZnO (CZO) nanophosphors with different Ce concentrations (Ce: 0, 2, 4, 6, and 8 wt.%) synthesized using the solid-state reaction method. The synthesized nanophosphors were characterized for their structural, morphological, optical, and photoconductivity (PC) properties using X-ray diffraction (XRD), field-effect scanning electron microscopy (FE-SEM), energy dispersive spectroscopy, Fourier-transform infrared (FT-IR), photoluminescence (PL), and PC measurements. The sharp diffraction peaks of XRD results exhibit the formation of crystalline hexagonal wurtzite ZnO nanostructures. The decrease in diffraction peak intensities of CZO with an increase in Ce concentrations signifies the deterioration of the ZnO crystal. FE-SEM images exhibit the good crystalline quality of nanophosphors composed of spherical- and elongated-shaped nanoparticles that are distributed consistently on the surface. The energy dispersive X-ray pattern of the 4 wt.% Ce-doped ZnO (CZO4 ) sample confirms the doping of Ce in ZnO. The presence of chemical bonds and functional groups corresponds to transmittance peaks established using FT-IR spectroscopy. Deconvoluted PL spectra show two major emission peaks, one in the UV region, which is near-band-edge, and the other in the visible region ranging from ~456 to 561 nm. In PC studies, current-voltage (I-V) and current-time (I-T) characteristics, that is, rise/decayin current under dark as well as UV light conditions, are also investigated. Efficient photoconduction is observed in CZO samples. The obtained results indicate the suitability to luminescent and photosensor applications.