Silver nanoparticles immobilized onto poly(4‐vinylpyridine)‐functionalized magnetic nanoparticles: A robust magnetically recyclable catalyst for oxidant‐free alcohol dehydrogenation

A heterogeneous and recyclable catalyst with a high loading of silver nanoparticles was synthesized via the silver nanoparticles being supported onto the surface of magnetic nanoparticles coated with poly(4‐vinylpyridine). The synthesized catalyst was used in the dehydrogenation of alcohols to corresponding carbonyl compounds. A broad diversity of alcohols was converted into their corresponding carbonyl compounds in excellent yields. The catalyst was easily recovered by applying an external magnetic field and reused for seven reaction cycles without considerable loss of activity. The catalyst was fully characterized using various techniques.     

Laminar heat transfer and fluid flow of two various hybrid nanofluids in a helical double-pipe heat exchanger equipped with an innovative curved conical turbulator

Journal of Thermal Analysis and Calorimetry - In the present study, the effect of inserting an innovative curved turbulator and utilizing two types of hybrid nanofluids on thermal performance in a...     

One‐Step Synthesis of Aromatic Terminal Alkynes from Their Corresponding Ketones under Microwave Irradiation

One‐step microwave‐assisted synthesis of phenylacetylenes 2a–j from the corresponding ketones 1a–j in the presence of a new reagent, PCl₅–pyridine, is described. The reaction is carried out under a simple operational and experimental procedure, avoiding the use of the complicated and harsh multistep reaction.     

Enhanced ethanol sensing properties of WO3 modified TiO2 nanorods

Pristine and WO₃ decorated TiO₂ nanorods (NRs) were synthesised to investigate n-n-type heterojunction gas sensing properties. TiO₂ NRs were fabricated via hydrothermal method on fluorine-doped tin oxide coated glass (FTO) substrates. Then, tungsten was sputtered on the TiO₂ NRs and thermally oxidised to obtain WO₃ nanoparticles. The heterostructure was characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) spectroscopy. Fabricated sensor devices were exposed to VOCs such as toluene, xylene, acetone and ethanol, and humidity at different operation temperatures. Experimental results demonstrated that the heterostructure has better sensor response toward ethanol at 200 °C. Enhanced sensing properties are attributed to the heterojunction formation by decorating TiO₂ NRs with WO₃.     

New Polydentate Trimethylsilyl Chalcogenide Reagents for the Assembly of Polyferrocenyl Architectures

A series of polychalcogenotrimethylsilane complexes Ar(CH₂ESiMe₃)_n, (Ar=aryl; E=S, Se; n=2, 3, and 4) can be prepared from the corresponding polyorganobromide and M[ESiMe₃] (M=Na, Li). These represent the first examples of the incorporation of such a large number of reactive ?ESiMe₃ moieties onto an organic molecular framework. They are shown to be convenient reagents for the preparation of the polyferrocenylseleno‐ and thioesters from ferrocenoyl chloride. The synthesis, structures, and spectroscopic properties of the new silyl chalcogen complexes 1,4‐(Me₃SiECH₂)₂(C₆Me₄) (E=S, 1 ; E=Se, 2 ), 1,3,5‐(Me₃SiECH₂)₃(C₆Me₃) (E=S, 3 ; E=Se, 4 ) and 1,2,4,5‐(Me₃SiECH₂)₄(C₆H₂) (E=S, 5 ; E=Se, 6 ) and the polyferrocenyl chalcogenoesters [1,4‐{FcC(O)ECH₂}₂(C₆Me₄)] (E=S, 7 ; E=Se, 8 ), [1,3,5‐{FcC(O)ECH₂}₃(C₆Me₃)] (E=S, 9 ; E=Se, 10 ) and [1,2,4,5‐{FcC(O)ECH₂}₄(C₆H₂)] (E=S, 11 illustrated; E=Se, 12 ) are reported. The new polysilylated reagents and polyferrocenyl chalcogenoesters have been characterized by multinuclear NMR spectroscopy (¹H, ¹³C, ⁷⁷Se), electrospray ionization mass spectrometry and, for complexes 1 , 2 , 3 , 4 , 7 , 8 , and 11 , single‐crystal X‐ray diffraction. The cyclic voltammograms of complexes 7 – 11 are presented.     

One-pot synthesis of 2H-indazolo[2,1-b]phthalazine-triones via nano γ-Al2O3/BF3/Fe3O4 as an efficient catalyst and theoretical DFT study on them

Experimental and computational studies were carried out for the synthesis of 2H-indazolo[2,1-b]phthalazine-triones using γ-Al₂O₃/BF₃/Fe₃O₄ as a nanocatalyst in optimized and solvent-free conditions. The most significant features of the existing protocol are easy preparation of the catalyst, short reaction times, environmentally benign, and milder reaction conditions. The analysis data were reported using the experimental results of this investigation, such as: H-NMR, FT-IR (Fourier-transform infrared spectroscopy), X-ray diffraction, vibrating-sample magnetometer, Thermal gravimetric analysis (TG-DTG), nitrogen adsorption isotherm, Field Emission Scanning Electron Microscopy, and Transmission electron microscopy images of nanocatalyst. In this study, 2H-indazolo[2,1-b]phthalazine-triones have also been theoretically investigated using DFT-B3LYP/6-31G method. Also, some of the physical chemistry properties have examined for conformers of products, which there was good agreement between the computational results and obtained experimental for the products.     

Aqueous-Mediated green synthesis of novel spiro[indole-quinazoline] derivatives using kit-6 mesoporous silica coated Fe3O4 nanoparticles as catalyst

In this work, a series of eight new spiro[3,4′]1,3-dihydro-2H-indol-2-one-2′-amino-4′,6′,7′,8′-tetrahydro-2′,5’(1’H,3’H)-quinazoline-diones were successfully synthesized through a three-component reaction of 1H-indole-2,3-diones (isatins), guanidine nitrate, and 1,3-cyclohexanediones, by use of Kit-6 mesoporous silica coated Fe₃O₄ nanoparticles (Fe₃O₄@SiO₂@KIT-6) as a highly efficient magnetically separable nanocatalyst in aqueous media at 60°C. Several notable features of thiseco-friendly protocol are high yields of products, short reaction times, operational simplicity, and the use of easily available and recyclable catalyst.