In the current industrial scenario, cobalt (Co) as a metal is of great importance but poses a major threat to the ecosystem because of its toxicity, but fewer studies have been conducted on its effects and alleviation strategies by using plant growth-promoting rhizo-bacteria (PGPR) and nanoparticles (NPs). Taking into consideration the positive effects of silver nanoparticles (Ag−NPs) and Bacillus cereus in reducing Co toxicity in plants, the present study was conducted. A pot experiment was conducted to determine the effects of individual application of different levels (10 and 20 µL) of B. cereus and Ag−NPs (25 and 40 mg L^⁻1) on Co accumulation, morpho-physio-biochemical attributes of Sorghum bicolor L. exposed to severe Co stress [0 (without Co stress), 15 and 25 mg kg⁻¹ in soil]. The research outcomes indicated that elevated levels of Co stress in the soil significantly (P ≤ 0.05) decreased plant growth and biomass, photosynthetic pigments, and gas exchange attributes. However, Co stress also induced oxidative stress in the plants by increasing malondialdehyde (MDA) and hydrogen peroxide (H₂O₂), which also induced increased compounds of various enzymatic and non-enzymatic antioxidants, organic acids, and also the gene expression and sugar content. Furthermore, a significant (P ≤ 0.05) increase in proline metabolism, was observed. Although, the application of B. cereus showed a significant (P ≤ 0.05) increase in plant growth and biomass, gas exchange characteristics, enzymatic and non-enzymatic compounds, and their gene expression and also decreased oxidative stress and also organic acid exudation pattern. The application of B. cereus and Ag−NPs decreased the proline metabolism in S. bicolor plants. Research findings, therefore, suggest that the application of B. cereus and Ag−NPs can ameliorate Co toxicity in S. bicolor, resulting in improved plant growth and composition under metal stress, as depicted by balanced antioxidant defense mechanism. These findings highlight the potential of nanotechnology and beneficial microbes as sustainable strategies for mitigating heavy metal toxicity and improving crop performance in contaminated soils, thereby contributing to environmentally resilient agricultural systems

Highly active catalysts for oxygen evolution reaction (OER) derived from transition metals are crucial for boosting the performance of catalytic electrolysis of water, a key technology for sustainable hydrogen production. This research highlights the design and synthesis of FeM@Co layered double hydroxide (LDH) nanoflowers, where M represents Co, Mn, or Ni, prepared through a facile two-step electrodeposition method. Introducing diverse transition metals significantly modulates the interfacial synergy between the nanostructured Co LDH and the FeM decoration, thereby tuning the electronic structure and electrocatalytic efficiency. Comparative evaluation of the hybrid structures revealed that FeNi@Co LDH nanoflowers exhibit the most remarkable OER activity, with an overpotential of only 266 mV at 100 mA∙cm⁻², a minimal Tafel slope of 21 mV∙dec⁻¹, and excellent durability over 50 h under prolonged operation at 100 mA∙cm⁻². Beyond half-cell studies, a full-cell electrolyzer employing FeNi@Co LDH serving as the anode, with Pt/C functioning as the cathode, delivered 10 mA∙cm⁻² at only 1.43 V, underscoring its high energy efficiency and practical viability. These findings highlight the promise of tailored FeM@Co LDH architectures as high-performance catalysts, contributing valuable knowledge to the purposeful design of advanced materials for efficient water-splitting and clean energy applications.

A simple one-pot protocol is described for the synthesis of dispiro[fluorene-9,3′-pyrazole-5′,4″-pyrazolidines] via a [3 + 2] cycloaddition reaction between 9-diazo-9H-fluorene (DF) and a series of (E/Z)-4-arylidene-1-phenylpyrazolidine-3,5-diones (APPs). In all cases, the cycloaddition proceeds with complete regioselectivity, affording a single regioisomeric framework as a pair of diastereomers through an endo approach. The structures and regiochemical outcomes of the cycloadducts were established by comprehensive 1D and 2D NMR spectroscopic analyses (¹H, ¹³C, DEPT-135, COSY, ¹H-HSQC, HMBC, and ROESY). The regiochemistry and mechanism of the cycloaddition reaction were investigated using density functional theory (DFT) calculations at the B3LYP/cc-pVTZ level of theory, supported by analysis of global and dual local electrophilicity and nucleophilicity descriptors. To rationalize the observed stereoselectivity, the relevant transition-state structures were located and optimized using a QST3-based transition-state search at the same level of theory. Global electron density transfer (GEDT) analysis revealed that the cycloaddition reactions are highly polar, with electron density flowing from 9-diazo-9H-fluorene (DF) toward the (E/Z)-4-arylidene-1-phenylpyrazolidine-3,5-dione (APP) framework. Consistently, molecular electrostatic potential surface (MESP) analysis showed that, in the energetically favored transition states, the reacting partners approach through regions of opposite electrostatic potential, leading to stabilizing electrostatic interactions between the two fragments. The computational results are consistent with the experimental observations and support a polar, synchronous one-step cycloaddition mechanism. The developed protocol affords the desired dispiro compounds in good to excellent yields (59–91%) with complete regioselectivity, providing a single regioisomeric framework as a pair of diastereomers. This work provides valuable insights into diazo-based cycloaddition chemistry and is expected to stimulate further research in the synthesis of structurally complex spiroheterocycles. Compared to previously reported approaches, the present method offers a simple one-pot strategy with high efficiency, complete regioselectivity, and operational simplicity.

Acetylation of 1-amino-5-(piperidin-1-yl)-N-phenyl-6,7,8,9-tetrahydrothieno[2,3-c]isoquinoline-2-carboxamide (3) with acetic anhydride afforded unexpected [1,3]oxazinothienoisoquinolinone derivative in an excellent yield instead of the expected N-phenylpyrimidothienoisoquinolinone. Diazotization of 3 using sodium nitrite in acetic acid and sulfuric acid yielded the corresponding triazinothienoisoquinoline, while the reaction with triethyl orthoformate in acetic acid produced N-phenylpyrimidine derivative 7. Chloroacetylation of compound 3 with chloroacetyl chloride in dioxane at 60–70°C yielded chloroacetamido compound 8, which underwent ring closure upon reflux in acetic anhydride to produce the chloromethyl oxazinone derivative 9. Oxazinone derivatives 5 and 9 underwent nucleophilic substitution upon treatment with ammonium acetate/acetic acid mixture and hydrazine hydrate to afford pyrimidinone …

This study investigated the insecticidal bioefficacy of seven compounds (1-7) against maize aphid (Rhopalosiphum maidis). Results indicated that LC₅₀ values ranged from 1.52 to 18.45 mg/L for nymphs and 23.96 to 80.73 mg/L for adults. Compound (6) demonstrated the highest potency, with LC₅₀ values of 1.52 mg/L against nymphs and 23.96 mg/L against adults, establishing it as the most effective analogue for potential aphid control. The other compounds also exhibited varying degrees of insecticidal activity. For nymphs, compound (5) was notably effective, followed by compound (7), and compound (3) with LC₅₀ values of 2.23, 2.37, and 2.45 mg/L, respectively, indicating their promising potential. Compounds (4), (2), and (1) showed comparatively lower efficacy against nymphs with LC₅₀ values of 12.19, 14.14, and 18.45 mg/L, respectively. Similarly, for adults of maize aphids, compounds (5), (7), and (3 …

Two novel polyamides, Poly(Oxa) and Poly(Pip), were successfully synthesized through the polycondensation of 1,4-bis(2-chloroacetamido)benzene with either 5,5′-(1,4-phenylene)bis(1,3,4-oxadiazole-2-thiol) or piperazine, respectively. Comprehensive computational, structural, morphological, thermal, and photophysical analyses revealed distinct structure–property relationships governed by the nature of the polymer backbone. Poly(Oxa), containing a heteroaromatic framework, exhibited pronounced conjugation and semi-crystallinity, confirmed by FT-IR and XRD analyses. This architecture imparted exceptional thermal stability (char yield: 42.4 %), high flame retardancy (LOI = 34.5 %), and a heterogeneous morphology with strong π–π stacking interactions, which enhanced methylene blue adsorption. Remarkably, Poly(Oxa) displayed excitation-dependent photoluminescence, shifting from deep-blue to …