Apurba Kumar Das

The challenges associated with Suzuki–Miyaura reactions when using costly, less-sustainable homogeneous catalysts have increased the surge of attempts to develop highly efficient, cost-effective, and sustainable heterogeneous catalysts.

Molecular electrocatalysis has emerged as a cutting‐edge approach for energy storage and conversion. In organic synthesis, it offers eco‐friendly alternatives to traditional redox methods. However, improving the efficiency and performance of molecular catalysts remains a key challenge. This study presents the synthesis of NTDA‐β‐alanine‐tethered TEMPO (2,2,6,6‐tetramethylpyridinyl‐ N ‐oxyl), which achieves efficient ex situ noncovalent immobilization over MWCNTs. This approach provides superior control over catalyst properties, enhances stability, and allows for easier regeneration or modification compared to in‐situ methods. The method efficiently oxidizes various aromatic, aliphatic, and optically active alcohols like terpenoids, while preserving the chiral integrity of optically active compounds. Additionally, the study explores the role of steric hindrance in oxidation, shedding light on the link between molecular structure and catalytic performance. It highlights the immobilized catalyst's remarkable reproducibility and high turnover frequencies (TOF), as confirmed through chronoamperometric analysis. Furthermore, the catalyst displayed excellent conversion when exposed to bulk electrocatalysis. This study presents an effective electrocatalytic method that employs ex‐situ immobilization to improve catalyst performance, stability, reproducibility, and adaptability, promoting more sustainable and precise organic transformations.

In synthetic chemistry and pharmaceuticals, azo aromatics are important building blocks with a wide range of applications. However, their environmentally‐friendly synthesis has not been extensively studied. Herein, we have synthesized the peptide bolaamphiphile‐based organic–inorganic nanohybrid architecture, on a nickel foam (NF) substrate. The electrodeposition method is used to synthesize a Bola/Ni‐Co nanohybrid (Bola = FW‐AdiA‐WF/Ni‐Co, AdiA = adipic acid, W = L‐tryptophan, F = L‐phenylalanine, Ni = nickel nitrate and Co = cobalt nitrate (2:2)) on nickel foam without the need for any additional conductive material or binder. The resulting electrocatalyst is highly effective in selectively facilitating the anodic azo coupling reaction (ACR) of aromatic amines, converting them into azo aromatics at ambient conditions. This reaction takes place in a 1 M KOH electrolyte at a current density of 15 mA in an undivided cell. The electrocatalyst is effective for a broad range of substrates and can tolerate various functional groups. During the electrosynthesis of azo aromatics, the substrate adheres to the surface of electrocatalyst, which prevents the competing oxygen evolution reaction (OER). The use of water as a solvent avoids the need for excessive chemicals, making this electrosynthesis method safe, cost‐effective, and environmentally friendly. Furthermore, the electrocatalyst is highly stable and can be reused for up to seven consecutive cycles. This method offers an energy‐efficient route for the synthesis of value‐added products with high yields for future prospectives.

Developing resilient and robust electrocatalysts devoid of noble metals is vital for facilitating the generation of O₂/H₂ from water electrolysis, particularly in catalyzing oxygen evolution reaction (OER) and urea oxidation reaction (UOR), respectively. Nickel‐based catalysts have attracted as part of global efforts to produce hydrogen from urea‐rich wastewater due to their high reaction rates and favorable long‐term stability. Two new mononuclear Ni^II‐embedded complexes, namely, [C₂₆H₃₈NiN₄O₄] (Complex 1) and [C₂₄H₃₂NiF₂N₄O₂] (Complex 2), are explored as a bifunctional catalyst for the OER and UOR herein. Complexes 1 and 2 crystallize in triclinic and monoclinic with space group 1 (2) & P 21/c (14), respectively. The OER outcomes of Complex 1 exhibit excellent performance, featuring a lower overpotential of 220 mV and reduced Tafel slope value of 82 mV dec⁻¹ at a benchmarking current density of 10 mA cm⁻² in 1 M KOH compared to Complex 2. Additionally, the results of UOR indicate that Complex 1 only requires 1.30 V potential to achieve the same current density which is significantly lower than other counterparts and most reported materials. Chronopotentiometry analysis reveals that Complex 1 is stable up to a longer period of 100 and 20 h in 1 M KOH and alkaline urea electrolyte, respectively.

Hydrogels derived from self-assembling peptides provide considerable benefits in tissue engineering including their biocompatibility and extensive molecular diversity. Short peptides are especially advantageous due to their ease of production, ability to self-assemble, and repeatability. However, their application is currently limited owing to possible toxicity resulting from the chemical modifications required for self-assembly and the coarse gelation conditions. Nucleobase-functionalized derivatives provide an opportunity to use naturally obtained species to minimize cytotoxicity. Therefore, nucleobase-functionalized hydrogels are currently attracting significant interest due to their varied architectures. Herein, we have synthesized a guanine-functionalized alanine derivative and investigated the formation of a coassembled hydrogel with guanosine. The development of the nucleic acid secondary structure within the coassembled hydrogel is studied using circular dichroism and wide-angle powder X-ray diffraction experiments. The thermoreversible nature of the coassembled hydrogel is explored. The biocompatibility of the coassembled hydrogel is evaluated by performing the MTT assay. The coassembled hydrogel is used for cell growth, and 2D cell cultures are carried out on fibroblast McCoy and epithelial A549 cell lines. Live-dead cell imaging is performed by staining with fluorescein diacetate and propidium iodide. The cell proliferation is studied over different time periods using the Alamar Blue assay. Cytoskeletal staining is performed on both cell lines to determine the impact of the coassembled hydrogel on the cells.

Fragile X-associated Tremor/Ataxia Syndrome (FXTAS)/Fragile X-associated Primary Ovarian Insufficiency (FXPOI) are conditions caused by an elevated level of CGG repeats in the 5' untranslated region (5'-UTR) of the Fragile X Mental Retardation 1 (FMR1) gene. These trinucleotide extended RNA repeats [r-(CGG)_exp] produce toxic homopolymeric proteins in neuronal cells via repeat-associated non-ATG (RAN) translation or formation of RNA foci. A promising therapeutic approach for such conditions involves identifying potent modulators, particularly those with high binding affinity and selectivity toward these expanded RNA repeats. We investigated the therapeutic potential of homoaromatic tyrosine peptides (2Y, 3Y, and 4Y) toward CGG repeat RNA by employing biophysical and cell model-based studies. Furthermore, administering the peptides from the early developmental stages in the Drosophila model of FXTAS also mitigated the disease symptoms. Results revealed that the peptides interact with r-(CGG)_exp in a thermodynamically advantageous manner and are highly selective for the GG-rich RNA motif. All three peptides correct alternative splicing flaws linked to FXTAS, reduce the synthesis and buildup of the FMR1polyG protein inclusion, and rapidly suppress cell cytotoxicity in both the cellular and Drosophila models. These findings show that homo aromatic tyrosine-based peptides targeting treacherous repeat RNAs are potential therapeutic tools for treating FXTAS/FXPOI.