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A ruthenium(II) aquo complex [Ru(dipic)(PPh3)2(OH2)], (1 A), bearing O,N,O‐coordinated 2,6‐dipicolinate was synthesized via reaction of [Ru(PPh3)3Cl2] with 2,6‐dipicolinic acid. Crystal structure of 1 A was determined. Utilizing 1 A as a synthon, three new complexes were synthesized. Reaction of 1 A with a bidentate NHC‐ligand, viz. 1‐methyl‐3‐(2′‐pyridyl)imidazole (IMeCN), afforded [Ru(dipic)(IMeCN)(PPh3)], (2 A). Similar reactions of 1 A with two pincer ligands, viz. 2,6‐bis(1′‐methyl imidazolyl)pyridine (IMeCNC) and 2,2′;6′,2"‐terpyridine (trpy), respectively yielded [Ru(dipic)(IMeCNC)(PPh3)], (3 A) and [Ru(dipic)(trpy)(PPh3)], (3 B). Structure of 2 A was optimized by DFT method. Structures of 3 A and 3 B were determined by X‐ray crystallography. In both 3 A and 3B the 2,6‐dipicolinate ligand was found to be N,O‐coordinated with one carboxy end remaining unbound to the metal center. Anticancer property of 2 A, 3 A and 3 B was studied and compared. Cytotoxicity of 3 A, studied against three selected cancer cell lines, viz. chronic myelogenous leukemia cell line (K562), hepatocellular carcinoma cell line (HepG2) and breast adenocarcinoma cell line (MCF7), was found to be the most promising. It displayed the best activity against K562, while it did not have any appreciable effect on its normal counterpart, viz. the human peripheral blood mononuclear cells (hPBMC). The comparative cytotoxicity studies indicated that presence of the C,N,C‐coordinated pincer NHC ligand in 3 A, together with presence of the free carboxylate end of N,O‐coordinated dipic ligand, are presumably responsible for its superior cytotoxic behavior. [ABSTRACT FROM AUTHOR]

In single‐step conversion of glycerol to propene, the intricate catalytic pathways with molybdenum and niobium catalysts remain elusive. While these catalysts can effectively accelerate the hydrogenolytic cleavage of the glycerol CO bonds, resulting in a high selectivity to propene, the routes have not been thoroughly studied. This study explores the reaction routes and the role hydrogen plays in determining the product distribution. The hydrodeoxygenation (HDO) of glycerol was investigated using various glycerol purities in both batch and continuous reaction modes. Remarkably, Mo(PO4)x and Nb(PO4)x demonstrated catalytic performance with raw glycerol, indicating that impurities had no detrimental effect on the catalyst's activity. In batch mode, a propene selectivity of 53% was achieved over Mo(PO4)x as the catalyst, highlighting the catalyst's stability under these conditions. In continuous operation, the highest product selectivity to propene (12%) was observed at low temperatures (573 K), while more C2 to C6 alkanes were formed at increased temperatures (623 and 673 K). Whereas a hydrogen atmosphere promotes formation of 2‐propenol, as primary precursor to propene, an inert atmosphere leads to increased formation of propanal and dissociation products. Our work has elucidated new routes to upcycle biorenewable glycerol to propene over Mo(PO4)x and Nb(PO4)x catalysts. [ABSTRACT FROM AUTHOR]

Chemical fixation of CO2 for the synthesis of valuable chemicals is very demanding in the context of green and sustainable chemistry. Herein, we report highly efficient silver‐loaded porous organic polymer catalysts for the exclusive N‐formylation and N‐methylation of amines under ambient reaction conditions using CO2 as a green C1 source. By adjusting the solvent and temperature of the reaction, the successful production of formamides and methylamines could be accomplished with high levels of selectivity and efficiency. POP‐based materials Ag@TTP‐1 and Ag@PAN‐T are utilized as low‐cost catalysts for both the N‐methylation and N‐formylation of primary and secondary amines and the product yields up to 98 % could be achieved. Ag@TTP‐1 demonstrated superior catalytic efficiency compared to Ag@PAN‐T in the N‐methylation and N‐formylation reactions. This result suggests that the grafting of Ag nanoparticles onto POP surface with a high surface area plays a crucial role in these CO2 fixation reactions. The above‐mentioned catalysts (Ag@TTP‐1 and Ag@PAN‐T) are characterized through powder XRD, FT IR spectroscopy, FE‐SEM, TEM, thermogravimetric techniques, N2 sorption and XPS analysis. Ag‐nanocatalysts demonstrated heterogeneous nature and high recycling efficiency for several cycles in this CO2 fixation reaction. [ABSTRACT FROM AUTHOR]

Porous organic polymers (POPs) have attracted substantial attentions over the years due to their exceptionally high specific surface areas, high chemical stability of the organic network and ease of surface functionalization with the desired organic groups. In this work, a triazine based POP (TrzPOP) was synthesized through Schiff base polycondensation reaction between a tetramine bearing triazine rings and phenolic–OH group rich dialdehyde. Ni nanoparticles (NiNP) synthesized independently were immobilized over TrzPOP to obtain the NiNP@TrzPOP composite catalyst. This TrzPOP possesses a high BET surface area of 1494 m2 g−1 and low band gap, which facilitates its role as visible light absorbent. NiNP@TrzPOP with N‐rich surfaces and phenolic–OH moieties displayed excellent photocatalytic activity in the CO2 photoreduction under mild reaction conditions. NiNP@TrzPOP composite selectively reduces CO2 to methanol. The turn over number (TON) for this photoreduction of CO2 under optimized reaction conditions is 270, which is considerably high comparing to other reported photocatalytic systems. Moreover, NiNP@TrzPOP composite catalytic system showed high recycling efficiency without noticeable decrease in its performance over five consecutive reaction cycles, suggesting its huge potential for large‐scale methanol synthesis from the renewable carbon source. [ABSTRACT FROM AUTHOR]

The escalating demand for the cost-effective synthesis of valuable fine chemicals has fueled the search for sustainable heterogeneous catalysts. Among these catalytic reactions, Knoevenagel condensation has emerged as a very demanding reaction due to its involvement in the synthesis of new C–C bond formation. Porous metal phosphates have attracted significant attention in catalysis due to their unique surface properties. In this study, we report the synthesis of a novel porous magnesium aluminum phosphate (MALPO) material through a hydrothermal template-free approach. MALPO exhibited very promising specific surface area and hierarchical porosity. Moreover, the plate-like morphology of the material can enhance the exposure of the catalytic sites located at the surfaces, leading to enhanced catalytic activity. MALPO demonstrated excellent catalytic performance, yielding a series of Knoevenagel products with up to 99% yield. Notably, the catalyst displayed remarkable recyclability, retaining its structural integrity throughout multiple reaction cycles. The findings highlight the potential of porous mixed-metal phosphates, exemplified by MALPO, as sustainable and efficient base catalyst for the synthesis of value-added chemicals, contributing to the growing demand of the chemical industry. Further investigations are warranted to explore their catalytic potential in diverse chemical transformations and optimize their performance for large-scale operations. [ABSTRACT FROM AUTHOR]

The intermingled interrelationship of Bacopa monnieri and human health dates backs to the ancient times in the history of ayurveda making the plant an enriched source of alternative drug development in a nontoxic manner. In recent years, research on the biological effects of Bacopa monnieri has flourished as promising neuroprotective, memory boosting and more importantly as both chemopreventive and anti-neoplastic agent. Each naturally synthesized chemical constituent identified from Bacopa monnieri leaf extract with different solvents, has significant anti-metastatic, anti-angiogenic and anti-proliferative activity on different type of cancer cells. In this context, a substantial literature survey allows a deep understanding of the involvement of specific bioactive molecules along with the whole plant extract of Bacopa monnieri with their divergent effective molecular pathways. This comprehensive review covers literature up to the year 2020 highlighting all the anticancer efficacy along with signaling pathways activated by secondary metabolites found in bacopa plant. [ABSTRACT FROM AUTHOR]

Hydrogen evolution reaction (HER) by electrochemical water splitting is one of the most active areas of energy research, yet the benchmark electrocatalysts used for this reaction are based on expensive noble metals. This is a major bottleneck for their large‐scale operation. Thus, development of efficient metal‐free electrocatalysts is of paramount importance for sustainable and economical production of the renewable fuel hydrogen by water splitting. Covalent organic frameworks (COFs) show much promise for this application by virtue of their architectural stability, nanoporosity, abundant active sites located periodically throughout the framework, and high electronic conductivity due to extended π‐delocalization. This study concerns a new COF material, C6‐TRZ‐TFP, which is synthesized by solvothermal polycondensation of 2‐hydroxybenzene‐1,3,5‐tricarbaldehyde (TFP) and 4,4′,4′′‐(1,3,5‐triazine‐2,4,6‐triyl)tris[(1,1′‐biphenyl)‐4‐amine]. C6‐TRZ‐TFP displayed excellent HER activity in electrochemical water splitting, with a very low overpotential of 200 mV and specific activity of 0.2831 mA cm−2 together with high retention of catalytic activity after a long duration of electrocatalysis in 0.5 m aqueous H2SO4. Density functional theory calculations suggest that the electron‐deficient carbon sites near the π electron‐donating nitrogen atoms are more active towards HER than those near the electron‐withdrawing nitrogen and oxygen atoms. [ABSTRACT FROM AUTHOR]

Developing a robust metal‐organic framework (MOF) which facilitates proton hopping along the pore channels is very demanding in the context of fabricating an efficient proton‐conducting membrane for fuel cells. Herein, we report the synthesis of a novel tetradentate aromatic phosphonate ligand H8L (L=tetraphenylethylene tetraphosphonic acid) based Ni‐MOF, whose crystal structure has been solved from single‐crystal X‐ray diffraction. Ni‐MOF [Ni2(H4L)(H2O)9(C2H7SO)(C2H7NCO)] displays a monoclinic crystal structure with a space group of P 21/c, a=11.887 Å, b=34.148 Å, c=11.131 Å, α=γ=90°, β=103.374°, where a nickel‐hexahydrate moiety located inside the void space of the framework through several H‐bonding interactions. Upon treatment of the Ni‐MOF in different pH media as well as solvents, the framework remained unaltered, suggesting the presence of strong H‐bonding interactions in the framework. High framework stability of Ni‐MOF bearing H‐bonding interactions motivated us to explore this metal‐organic framework material as proton‐conducting medium after external proton doping. Due to the presence of a large number of H‐bonding interactions and the presence of water molecules in the framework we have carried out the doping of organic p‐toluenesulfonic acid (PTSA) and inorganic sulphuric acid (SA) in this Ni‐MOF and observed high proton conductivity of 5.28×10−2 S cm−1 at 90 °C and 98% relative humidity for the SA‐doped material. Enhancement of proton conductivity by proton doping under humid conditions suggested a very promising feature of this Ni‐MOF. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) containing multiple carboxylate and sulfonate linkers together with positively charged rare earth metals can offer new opportunities in heterogeneous catalysis. The high efficiency of the CO2 fixation reaction at low temperature and pressure over MOF-based catalysts is very challenging as it involves the renewable feedstock CO2 as a C1 source for the synthesis of value-added fine chemicals. Here we develop a new microporous La(III) based MOF through the solvothermal reaction using 5-sulfoisophthalic acid as the ligand, and the resulting La-5-SIP-MOF showed a high catalytic activity for the synthesis of cyclic carbonates from epoxides through the CO2 fixation reaction at room temperature and moderate (3–5 MPa) pressure. The optimum product yield was obtained in only 1 h reaction with the desired yield up to 98%. The La-5-SIP-MOF was characterized by using different analytical techniques such as single crystal X-ray diffraction, FTIR, PXRD, N2 adsorption/desorption study, UHR-TEM, solid UV-vis spectroscopy and TGA. The recycling efficiency and the structural stability of this MOF catalyst is also very high, suggesting a sustainable future of this La-MOF in heterogeneous catalysis. [ABSTRACT FROM AUTHOR]

This study investigates the in vitro antioxidant and antimicrobial activities of eight extracts obtained from the dried barks of Commiphora berryi and Commiphora caudata (Burseraceae). The radical scavenging activity was assessed by 1,1-diphenyl-2-picryl hydrazyl (DPPH) and nitric oxide assays. The methanolic extracts of C. berryi and C. caudata showed significant DPPH radical scavenging activity, with IC50 values of 26.92 and 21.16 µg mL−1, respectively, and low radical scavenging activity against the nitric oxide assay. The antimicrobial activity of the plants was tested against the Gram-positive and Gram-negative bacteria. The ethyl acetate, chloroform and petroleum ether extracts of C. berryi showed good antibacterial activity against Pseudomonas aeruginosa, with a minimum inhibitory concentration (MIC) of 0.26 mg mL−1, whereas the ethyl acetate and methanol extracts of C. caudata showed moderate antimicrobial activity with an MIC of more than 2.0 mg mL−1 against P. aeruginosa compared to the petroleum ether and chloroform extracts, which showed an MIC of 1.1 mg mL−1. The methanolic extracts of C. berryi and C. caudata also showed moderate cytotoxic activity against a human mammary carcinoma cell line (MCF-7), with values IC50 of 82.6 and 88.4 µg mL−1, respectively. [ABSTRACT FROM PUBLISHER]

Hydrogen evolution reaction (HER) by electrochemical water splitting is one of the most active areas of energy research, yet the benchmark electrocatalysts used for this reaction are based on expensive noble metals. This is a major bottleneck for their large-scale operation. Thus, development of efficient metal-free electrocatalysts is of paramount importance for sustainable and economical production of the renewable fuel hydrogen by water splitting. Covalent organic frameworks (COFs) show much promise for this application by virtue of their architectural stability, nanoporosity, abundant active sites located periodically throughout the framework, and high electronic conductivity due to extended π-delocalization. This study concerns a new COF material, C 6 -TRZ-TFP, which is synthesized by solvothermal polycondensation of 2-hydroxybenzene-1,3,5-tricarbaldehyde (TFP) and 4,4',4''-(1,3,5-triazine-2,4,6-triyl)tris[(1,1'-biphenyl)-4-amine]. C 6 -TRZ-TFP displayed excellent HER activity in electrochemical water splitting, with a very low overpotential of 200 mV and specific activity of 0.2831 mA cm -2 together with high retention of catalytic activity after a long duration of electrocatalysis in 0.5 m aqueous H 2 SO 4 . Density functional theory calculations suggest that the electron-deficient carbon sites near the π electron-donating nitrogen atoms are more active towards HER than those near the electron-withdrawing nitrogen and oxygen atoms., (© 2021 Wiley-VCH GmbH.)