Single-pot tandem oxidative/C-H modification amidation process using ultrasmall PdNP-encapsulated porous organosilica nanotubes

Herein, we studied a single-pot method with a dual catalysis process towards the conversion of primary aromatic alcohols to amides using ultrasmall PdNPs of controlled uniform size (1.8 nm) inside hybrid mesoporous organosilica nanotubes (MO-NTs). The catalyst exhibited excellent performance in water under mild conditions and showed high stability. The catalytic activity towards the tandem oxidation of alcohols in the presence of amine salts and H2O2 to their corresponding amides without producing byproducts was evaluated, and high yields were obtained for all products. The structure of the organosilica nanotubes containing palladium nanoparticles was investigated using various characterization techniques such as XRD, TEM, BET, solid-state 29Si NMR and solid-state 13C CP MAS NMR. Catalyst recycling tests showed that the catalytic power of PdNPs@B-SNTs was preserved after 8 cycles and a slight decrease in catalyst activity was observed.

Biosynthesis of AgNPs onto the urea-based periodic mesoporous organosilica (AgxNPs/Ur-PMO) for antibacterial and cell viability assay

Nano-size silver particles were stabilized on the inner surfaces of urea based periodic mesoporous organosilica (Ur-PMO). Aqueous extract of Euphorbia leaves as a sustainable and green reducing agent was applied for Ag-nanoparticles growth into the Ur-PMO channels. Physical and chemical properties of organosilica materials synthesized using various techniques such as FT-IR, small-angle XRD, PXRD, FESEM, TEM, SEM-EDX and atomic absorption spectrometry (AAS) were examined. Finally, the AgNPs/Ur-PMO were investigated on cell viability assay. An in vitro cytotoxicity test using MMT assay displayed that the designed material has good biocompatibility and could be a promising candidate for biomedical applications. The results also showed that the AgNPs/Ur-PMO compounds (especially, PMO; 1.27% AgNPs) had relatively good antibacterial and antibiofilm effects. It seems that the use of these compounds in hospital environments can reduce nosocomial infections as well as reduce antibiotic-resistant bacteria.

Laser-induced cavities with a controllable shape in nanoporous glass

The formation of birefringent structures inside nanoporous glass by femtosecond laser pulses was investigated. The laser-modified region is shown to be a cavity whose shape depends on the number of pulses. The shape of the void cross section varied from circle to ellipse when increasing the number of pulses from one to three. A layer of non-porous dense glass was revealed around the cavity. The cross section of this layer is nearly circular, regardless of the cavity shape and number of pulses in the investigated range. The mechanism of elongated cavity formation based on aniostropic light scattering on the spherical cavity is proposed.

Sodium alginate passivated CuInS2/ZnS QDs encapsulated in the mesoporous channels of amine modified SBA 15 with excellent photostability and biocompatibility

We herein report the synthesis of CuInS₂/ZnS (CIS/ZnS) quantum dots (QDs) via a greener method followed by sodium alginate (SA) passivation and encapsulation into mesoporous channels of amine modified silica (SBA15-NH₂) for improved photostability and biocompatibility. The as-synthesized CIS/ZnS QDs exhibited near infrared emission even after SA passivation and silica encapsulation. Transmission electron microscopy (TEM) and Small angle X-ray diffraction (XRD) revealed the mesoporous nature of the SBA-15 remained stable after loading with the SA-CIS/ZnS QDs. The effective encapsulation of SA-CIS/ZnS QDs inside the pores of SBA15-NH₂ matrix was confirmed by Brunauer-Emmett-Teller (BET) pore volume analysis while the interaction between the QDs and SBA15-NH₂ was confirmed using Fourier transform infrared (FTIR) spectroscopy. The photostability of the QDs was greatly enhanced after these modifications. The resultant SA-CIS/ZnS-SBA15-NH₂ (QDs-silica) composite possessed remarkable biocompatibility towards lung cancer (A549) and kidney (HEK 293) cell lines making it a versatile material for theranostic applications.

K. Raj KR, Ghodekar MM, Patil VS, Gopinath CS, Raja T. Phase Transfer Ceria-Supported Nanocatalyst for Nitrile Hydration Reaction

The present study elaborates the catalytic effect of rare-earth metal oxides (Sm₂O₃ and La₂O₃) over ceria as a support phase transfer catalyst. The synthesized catalysts have been subjected to different characterization techniques, such as field-emission scanning electron microscopy, high-resolution transmission electron microscopy, powder X-ray diffraction, N₂ adsorption-desorption (BET surface analysis), temperature-programmed desorption study (NH₃/CO₂-TPD), Fourier transform infrared, Raman analysis, and X-ray photoelectron spectroscopy to get better insights into the catalytic activity of the catalysts for hydration of nitrile.

Development of Sulfonic-Acid-Functionalized Mesoporous Materials: Synthesis and Catalytic Applications

Sulfonic acid based mesostructures (SAMs) have been developed in recent years and have important catalytic applications. The primary applications of these materials are in various organic synthesis reactions, such as multicomponent reactions, carbon-carbon bond couplings, protection reactions, and Fries and Beckman rearrangements. This review aims to provide an overview of the recent developments in the field of SAMs with a particular emphasis on the reaction scope and advantages of heterogeneous solid acid catalysts.

The influence of bovine serum albumin-modified silica on the physicochemical properties of poly(vinyl alcohol) nanocomposites synthesized by ultrasonication technique

In this study, for the first time polymeric nanocomposite (NC) films of poly(vinyl alcohol)/SiO₂@bovine serum albumin (PVA/SiO₂@BSA) were synthesized by solution casting method under facile and fast method of sonication. In this regard, SiO₂ nanoparticles (NPs) were modified by BSA, at room temperature by using phosphate buffer and ultrasonic-assisted method. Then, PVA/SiO₂@BSA NCs were prepared by insertion of variant amount (3, 6 and 9wt%) of SiO₂@BSA into the PVA matrix, under ultrasonic irradiation. The morphological traits of the NCs were surveyed by Fourier transform infrared spectroscopy, transmission electron microscopy, X-ray diffraction and field emission scanning electron microscopy. It was detected that NPs incorporation didn't remarkably affect the crystallinity and morphology of the NCs. TEM images indicated that the inserted NPs have good diffusions in the PVA matrix, and their embedment in the matrix significantly upgraded its thermal, optical and mechanical behaviors. The tensile strength showed more than 2-fold increase and the thermal stability exhibited about 37% enhancement that was higher, in comparison with those of the similar NCs. This showed that the prepared NCs can have potential application in food packaging.∗∗∗.

Hexagonal Mesoporous Silica-Supported Copper Oxide (CuO/HMS) Catalyst: Synthesis of Primary Amides from Aldehydes in Aqueous Medium

Hexagonal mesoporous silica (HMS)-supported copper oxides (CuO/HMS) have been prepared by a sol-gel method and characterized by X-ray diffraction, FTIR spectroscopy, transmission electron microscopy, N₂ sorption, inductively coupled plasma (ICP), X-ray photoelectron spectroscopy (XPS), H₂ temperature-programed reduction (TPR), NH₃ temperature-programed desorption (TPD), and high-resolution (HR)-TEM techniques. An analysis of these results revealed a mesoporous material system with a high surface area (974 m²  g^-1 ) and uniform pore-size distribution. The catalytic efficacy of CuO on the HMS support with varying Cu loadings (1, 3, 5, 10, and 15 wt %) was investigated for the transformation of aldehydes to primary amides; 3 wt % CuO/HMS exhibited good catalytic performance with good to excellent yields of amides (60-92 %) in benign aqueous medium. The intrinsically heterogeneous catalyst could be recovered after the reaction and reused without any noticeable loss in activity.

Cu(ii)-grafted SBA-15 functionalized S-methylisothiourea aminated epibromohydrin (SBA-15/E-SMTU-CuII): a novel and efficient heterogeneous mesoporous catalyst

The catalytic activity of novel synthesized SBA-15/E-SMTU-Cu^II nanocatalyst was investigated for the green, one-pot, pseudo five-component synthesis of tetrahydropyridine derivatives.

Copper(II) Acetate-Catalysed Conversion of Aldoximes to Amides under Mild Conditions

A mild method for the metal-catalysed conversion of aldoximes to amides has been achieved by the combined use of copper(II) acetate and MeCN in EtOH under reflux. The presence of a catalytic amount of MeCN (0.05 equiv.) accelerated the reaction and improved the yield. Aryl, heteroaryl and alkyl aldoximes were transformed into the corresponding amides in moderate to good yield. 2-Furyl and 2-thiophenyl aldoximes, which possess a heteroatom lone pair positioned ortho to the oximido group, showed enhanced reactivity, and the corresponding amides were obtained in excellent yield.

Modifiable diyne-based covalent organic framework: a versatile platform for in situ multipurpose functionalization

A COF material (TCD) containing diynes as both building blocks and active sites was prepared by microwave irradiation and employed as a versatile platform for the preparation of diverse functional materials.

Efficient tandem aqueous room temperature oxidative amidations catalysed by supported Pd nanoparticles on graphene oxide

Pd nanoparticles deposited onto graphene oxide nanosheets (SE-GO/Pd_NPs) were found to successfully promote two oxidative processes for the synthesis of amides, providing alternative possibilities to these important compounds.

Highly efficient synthesis of primary amides via aldoximes rearrangement in water under air atmosphere catalyzed by an ionic ruthenium pincer complex

An ionic Ru pincer complex was demonstrated to be highly efficient catalyst for conversion of aldoximes and aldehydes into corresponding primary amides with environmental benignity, operational convenience and catalytic loading as low as 0.5 mol%.

Highly efficient and recyclable copper based ionic liquid catalysts for amide synthesis

Copper based ionic liquids have been successfully prepared for the synthesis of primary, secondary and tertiary amides under mild reaction conditions.

Catalytic synthesis of amides via aldoximes rearrangement

This Feature article provides a comprehensive overview of the developments achieved in the catalytic synthesis of amides via rearrangement of aldoximes.

AIEE active perylene bisimide supported mercury nanoparticles for synthesis of amides via aldoximes/ketoximes rearrangement

AIEE active perylene bisimide derivatives 3 serve as reactors and stabilizers for the preparation of HgNPs which exhibit high catalytic efficiency in the synthesis of amides via aldoximes/ketoximes rearrangement.