Unusually facile syntheses of [RuII(bpy)3]2+ (bpy = 2,2′-bipyridine) and [RuII(phen)3]2+ (phen = 1,10-phenanthroline)

The salts [Ru^II(L–L)₃](CF₃SO₃)₂ (L–L = bpy or phen) have been prepared in high yields via reactions of [Ru^II(DMF)₆](CF₃SO₃)₂ (DMF = N,N-dimethylformamide), generated in situ by reduction of [Ru^III(DMF)₆]-(CF₃SO₃)₃, with an excess of bpy or phen at room temperature in DMF solutions.     

Dendrimer-encapsulated copper(II) immobilized on Fe3O4@SiO2 NPs: a robust recoverable catalyst for click synthesis of 1,2,3-triazole derivatives in water under mild conditions

Research on Chemical Intermediates - In this paper, we have introduced Fe3O4@SiO2-dendrimer-encapsulated Cu(II) as a heterogeneous reusable catalyst for Cu-catalyzed azide-alkyne cycloaddition...     

An efficient method for synthesis of acylals from aldehydes using multi-walled carbon nanotubes functionalized with phosphonic acid(MWCNTs-C-PO_3H_2)

MWCNTs-C-PO_3H_2 has been used as an efficient,heterogeneous and reusable nanocatalyst for synthesis of acylals from aldehydes under solvent-free conditions at room temperature.A wide range of aldehydes was studied and corresponding products were obtained in good to excellent yields in short reaction times.Nanocatalyst can be easily recovered by centrifuge and reused for subsequent reactions for at least five times without deterioration in catalytic activity.The major advantages of the present method are high yields,short reaction time,recyclable catalyst and solvent-free reaction conditions at room temperature.     

One-pot synthesis of diethyl 1-hydroxyphophonic esters on the surface of basic methal oxides under solvent free conditions

The effect of a series of metal oxides on synthesis of diethyl 1-hydroxyphosphonates under solvent free condition was studied and the results showed that calcium oxide was the most efficient reagent than the others for preparation of the title compounds.     

Green,cost‐effective and efficient procedure for Heck and Sonogashira coupling reactions using palladium nanoparticles supported on functionalized Fe3O4@SiO2 by polyvinyl alcohol as a highly active,durable and reusable catalyst

A novel heterogenized organometallic catalyst was synthesized by coordinating palladium with polyvinyl alcohol‐functionalized Fe₃O₄@SiO₂ nanospheres. This novel catalyst was characterized using Fourier transform infrared spectroscopy, X‐ray diffraction, transmission electron microscope, field emission scanning electron microscope, dynamic light scattering, UV–vis spectroscopy, X‐ray photoelectron spectroscopy, energy dispersive X‐ray analysis, thermogravimetric analysis and inductively coupled plasma analysis. The prepared palladium nanoparticles supported on polyvinyl alcohol functionalized Fe₃O₄@SiO₂ nanoparticles were successfully applied as a magnetically recyclable catalyst in Heck and Sonogashira coupling reactions in water. They showed remarkable activity toward aryl halides (I, Br, Cl) using very low palladium loading in excellent yields and demonstrated high TONs (mmol of product per mmol of catalyst). Also, the catalyst could be magnetically separated and reused seven times without any appreciable loss of catalytic activity.     

Nitrogen Ligand Complexes of Metal Chlorides as Effective Catalysts for the Highly Regio- and Chemoselective Silylation of Hydroxyl Groups with Hexamethyldisilazane (HMDS) at Room Temperature

Zn(bipy)₃Cl₂, Fe(bipy)Cl₃, and Fe(tpp)Cl are effective catalysts for silylation of hydroxy groups with HMDS at room temperature in dry CH₃CN. High selectivity is observed between primary and secondary hydroxy functional groups. This method absolutely discriminates other functional groups containing labile hydrogen atoms.     

Preparation and characterization of multi-walled carbon nanotubes (MWCNTs), functionalized with phosphonic acid (MWCNTs–C–PO3H2) and its application as a novel,efficient, heterogeneous,highly selective and reusable catalyst for acetylation of alcohols,phenols, aromatic amines,and thiols

A novel, efficient, heterogeneous, and reusable multi-walled carbon nanotubes (MWCNTs), functionalized with phosphonic acid (MWCNTs–C–PO₃H₂) has been synthesized. The synthesized CNTs were characterized using some electron microscopic techniques such as scanning electron microscopy (SEM), atomic force microscopy (AFM), Energy dispersive X-ray spectroscopy (EDAX), and also some thermal and spectroscopic methods such as thermogravimetry (TG). The nitrogen adsorption behavior of the MWCNTs–C–PO₃H₂ catalyst was evaluated using the TG instrumentation system at 25 °C. The catalyst was applied successfully for highly efficient and selective acetylation of alcohols, phenols, thiols and aromatic amines with acetic anhydride at room temperature under solvent-free conditions. The reusability of the catalyst was checked and the recovered catalyst was reused for five runs without significant loss in activity.     

Functionalization of superparamagnetic Fe3O4@SiO2 nanoparticles with a Cu(II) binuclear Schiff base complex as an efficient and reusable nanomagnetic catalyst for N‐arylation of α‐amino acids and nitrogen‐containing heterocycles with aryl halides

Fe₃O₄@SiO₂ nanoparticles was functionalized with a binuclear Schiff base Cu(II)‐complex (Fe₃O₄@SiO₂/Schiff base‐Cu(II) NPs) and used as an effective magnetic hetereogeneous nanocatalyst for the N‐arylation of α‐amino acids and nitrogen‐containig heterocycles. The catalyst, Fe₃O₄@SiO₂/Schiff base‐Cu(II) NPs, was characterized by Fourier transform infrared (FTIR) and ultraviolet‐visible (UV‐vis) analyses step by step. Size, morphology, and size distribution of the nanocatalyst were studied by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and dynamic light scatterings (DLS) analyses, respectively. The structure of Fe₃O₄ nanoparticles was checked by X‐ray diffraction (XRD) technique. Furthermore, the magnetic properties of the nanocatalyst were investigated by vibrating sample magnetometer (VSM) analysis. Loading content as well as leaching amounts of copper supported by the catalyst was measured by inductive coupled plasma (ICP) analysis. Also, thermal studies of the nanocatalyst was studied by thermal gravimetric analysis (TGA) instrument. X‐ray photoelectron spectroscopy (XPS) analysis of the catalyst revealed that the copper sites are in +2 oxidation state. The Fe₃O₄@SiO₂/Schiff base‐Cu(II) complex was found to be an effective catalyst for C–N cross‐coupling reactions, which high to excellent yields were achieved for α‐amino acids as well as N‐hetereocyclic compounds. Easy recoverability of the catalyst by an external magnet, reusability up to eight runs without significant loss of activity, and its well stability during the reaction are among the other highlights of this catalyst.     

Synthesis of Derivatives of (1R*,10aR*)-1-Azido-10-benzylidene-4-(diethylphosphono)-1,2,10,10a-tetrahydro-2-oxo-4H-azeto[1,2-a]pyrido[1,2-d]pyrazin-9-ylium Bromide

The synthesis of some derivatives of the title compound VI is described. Bromination of diethyl (cis-3-azido-2-oxo-4-styrylazetidin-1-yl)(pyridin-2-yl)methylphosphonate ( 6 ) in MeOH gave tricyclic β-lactam 7 , while similar bromination of diethyl (cis-3-azido-2-oxo-4-vinylazetidin-1-yl)(pyridin-2-yl)methylphosphonate ( 9 ) afforded tri-cyclic β-lactam 10 . Mechanisms for these transformations are proposed (Schemes 1 and 2).