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This review article describes the designing and aptness of diverse range of cerium-based catalysts for the oxidation of benzyl alcohols (Bz-OLs) in producing exclusively benzaldehydes (Bz-ALs) in the presence of eco-friendly oxidants. The discussion highlights the significance of surface and structural properties inherent to cerium-based catalysts, including the abundance of oxygen vacancies, the redox properties of Ce3+/Ce4+ couple, their acid-base characteristics and morphology influence, which play crucial roles in substrate adsorption, reorganization of bonding between substrate and oxidant in promoting selective oxidation reactions. The consolidated data tables (1-4) comprising the best conditions optimized with various ceria based heterogeneous reported so far between the years 2019-2024 is included in the following sections to assess the catalyst design and performance. [ABSTRACT FROM AUTHOR]

At 550°C and atmospheric pressure, clean hydrogen was produced through CH4 cracking on a ceria modified silica supported Ni catalyst. A high proportion of Ni surface area on 20Ni/2wt%CeO2-SiO2 demonstratedbetter H2 yields. The graphitic nature of the deactivated catalyst was established by TEM, XRD analyses and the distinction between ordered and disordered carbon was established by Raman spectroscopy. The high H2 yields produced by 20Ni/2wt%CeO2-SiO2 catalyst was explained due to high nickel dispersion and an improved surface area of the nickel as assessed by H2 pulse chemisorption. [ABSTRACT FROM AUTHOR]

Imines are certainly important constituents of many biomolecules, pharmaceuticals, agrochemicals, and fine chemicals. This review article highlights the standard protocols reported so far for the selective synthesis of imines via catalyzed and non-catalyzed (i) oxidative coupling of primary amines and (ii) oxidation of secondary amines in the presence of some competent/resourceful oxidants other than molecular O2 such as tert-butyl hydroperoxide (TBHP), H2O2, hypervalent iodines, persulfate, hypochlorite, electroactive species and graphene oxide. Indeed, the use of such oxidants offers a cost-effective experimental set-up, operational simplicity and also minimization of by-products. The cooperativity between catalyst, amine substrate, and oxidant is discussed in this review to understand the proposed mechanisms. Three consolidated data tables (Table 1, 2 & 3) are prepared to provide the summary of optimized reaction conditions (type of catalyst, type of oxidant, choice of solvent, amine-to-oxidant ratio, reaction time/temperature, conversion of amine, yield/selectivity of imine) of each article published to have a comparison. [ABSTRACT FROM AUTHOR]

An additive free, simple and efficient in situ PdNPs in PEG‐400 catalyzed and acetamide mediated hydration of nitriles to amides with broad substrate scope was developed herein for the first time. The in situ PdNPs recovered after first catalytic cycle of nitrile hydration sequence have been reused successively for four times. [ABSTRACT FROM AUTHOR]

This study explores a rational synthesis of a molybdenum‐promoted Ce−Si mixed oxide catalyst (MoO3/CeO2−SiO2) to regulate synergies between MoO3 and SiO2 dopant on CeO2, achieving high selectivity in solvent‐free catalytic oxidative coupling of amines to imines using molecular O2 as the oxidant. Comparative efficiency tests were conducted with bare CeO2, CeO2−SiO2, and MoO3/CeO2 catalysts. Characterization techniques, including XRD, Raman spectroscopy, N2‐adsorption‐desorption analysis, FTIR, NH3−TPD, TEM, and XPS, were employed to assess textural properties, acidic features, promoter and dopant dispersion in CeO2 lattice, and oxygen defects. Mo/Ce−Si catalyst exhibited superior acidic sites and a higher concentration of Ce3+ ions (Iu/ITotal), indicating increased oxygen vacancies. This catalyst demonstrated exceptional performance in the oxidative coupling of benzylamine, providing higher conversion and selectivity to the corresponding imine. Remarkably, the Mo/Ce−Si catalyst maintained consistent performance over five recycling runs. The catalyst also proved effective for the selective oxidative coupling of various amine substrates with diverse steric and electronic properties. Experimental results confirmed a plausible reaction mechanism within the concise catalyst design. [ABSTRACT FROM AUTHOR]

The mono or single oxides of alkaline earth metals such as CaO and MgO are a type of non-toxic and non-corrosive solid-base heterogeneous catalysts. Nevertheless, these mono oxide particles can agglomerate and form larger and less active particles at certain temperatures and reduces their catalytic activity. Therefore, the use of thermally stable CaO-MgO binary oxides is recommended. Further, the possible synergistic interactions between two metal centers provides cooperative catalytic behavior to improve catalytic activity compared to their single oxide counterparts. Therefore, the main theme of this review article is to highlight the ability of reported CaO-MgO based alkaline earth binary oxides as cost-effective and efficient solid-base catalysts in variety of organic transformations and to expand their scope in many other unexplored non-asymmetric organic transformations. Literature survey reveals that CMBOs are highly considerable in optimizing recognized organic transformations such as Transesterification, Knoevenagel/Aldol condensations, Isomerization, Oligomerization, Acetylation, Henry reaction, Alcoholysis, Aza-Michael addition, Cracking of Alkanes, H2-production via steam reforming, Photodegradation of organic pollutants and so forth. The literature survey further visualizes that the surface properties of CMBOs such as Brønsted/ Lewis's basicity, surface area, particle size, structural diversity, Ca: Mg ratios and synergism between Ca and Mg in CMBOs are very useful to promote them as efficient catalysts compared to their single oxide counterparts (pure CaO and pure MgO). The rightness of proposed mechanisms of abovementioned organic reactions by CMBO catalysts is elicited by this review. Moreover, the precursors for CMBOs are inexpensive, highly abundant and eco-compatible. Apart from the catalytic applications, the suitability of the CMBOs in sorption studies including CO2 uptake, ethanol steam reforming, and heavy metal ion removal is also covered. [ABSTRACT FROM AUTHOR]

A base‐free and efficient tandem one‐pot α‐ketoamide bond formation via tert‐butyl hydroperoxide (TBHP) mediated oxidative coupling of α‐hydroxy acetophenones with primary and secondary amines under Ag(I)‐N‐Heterocyclic carbene (Ag(I)−NHC) catalysis in water was developed herein for the first time. [ABSTRACT FROM AUTHOR]

This review presents an overview of the work on Au(I)-NHC chemistry. The efficiency of different synthetic strategies of Au(I)-NHCs is discussed. Transmetallation of Ag(I)-NHCs appears to be an easy method as compared with the others. The influence of aurophilicity "a traditional property of a Au(I) center" in making the supramolecular assemblies is also covered. The combination of the Au(I) center with NHCs has great potential in the fields of medicine, catalysis, liquid crystal, and optoelectronic. Key words: gold-carbenes, silver-carbenes, carbene transfer, aurophilicity. Dans ce travail, on presente une revue des travaux effectues dans le domaine de la chimie du Au(I)-NHC. On discute de l'efficacite des diverses strategies de synthese des Au(I)-NHC. Par rapport a d'autres methodes, la transmetallation des Au(I)-NHC semble la methode la plus appropriee. On a aussi examine l'influence du caractere aurophile, une propriete traditionnelle du centre Au(I), dans l'elaboration d'assemblages supramoleculaires. La combinaison du centre Au(I) avec des NHC possede un grand potentiel dans les domaines de la medecine, de la catalyse, des cristaux liquides et de l'optoelectronique. Mots cles : or-carbenes, argent-carbenes, transfert de carbene, caractere aurophile. [Traduit par la Redaction]

Herein, we first time developed a simple, readily available, clean and efficient CuCN/[bmim][PF6] system for the one-pot synthesis of 3-aminoindolizines using commercially available starting materials which included pyridine-2-carbaldehyde, secondary amines, and terminal alkynes. As well, the CuCN/[bmim][PF6] system was reused six times without any appreciable change in its activity. [ABSTRACT FROM AUTHOR]

A stoichiometric C-H activation/decarbonylation of salicylaldehyde by [(η6- p-cymene)RuCl2]2 gave a carbonyl derivative [(η6- p-cymene)RuCl(CO)(Ph-O)] ( 1) without the use of CO gas. A variety of polar phosphines were then incorporated into compound 1 to give new RuII cationic catalysts, [(η6- p-cymene)Ru(CO)(Ph-O)L]BF4 ( 2- 8). These were used to catalyse the hydrothiolation of alkynes with a range of thiols in aqueous THF to give anti-Markovnikov E-linear vinyl sulfides in high yields. [ABSTRACT FROM AUTHOR]