A one-pot access to pyridine/benzo fused cyclododecanes via multi-component tandem reactions

A facile syntheses of novel poly-substituted pyridine/benzo fused cyclododecane hybrid heterocycles have been achieved through one-pot multi-component tandem strategy employing cyclododecanone, aromatic aldehydes and malononitrile.     

Synthesis,characterization and biological analysis of transition metal complexes with macro cyclic ligands derived from adipic acid,ethylenediamine with diethyloxalate and diethylmalonate

Macro-cyclic ligands from adipic acid, ethylenediamine with diethyloxalate and diethylmalonate and their respective metal complexes of Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) with macro cyclic ligands (LO) and (LM) L [N,N′-bis(2-aminoethyl)hexanediamide] were synthesized successfully. These metal complexes were characterized by Fourier transform infrared, ultraviolet visible spectrometry, proton nuclear magnetic resonance spectroscopy, and mass Spectrometry, CHNS and thermogravimetric analysis. The elemental analysis confirms the structures for Mn(II), Co(II) and Ni(II) complexes similar to octahedral geometry, Cu(II) complexes as a square planar geometry and Zn(II) complexes in the tetrahedral geometry. The molar conductivities of all the metal complexes were taken in 10^?3 M DMSO, and values of all the metal complexes showed their electrolytic nature which indicates the presence of chloride ions. Thermal analysis supports as the metal complexes are thermally stable. The result of antimicrobial activity against various microorganisms confirms that the metal complexes are potent bactericides and fungicides than the ligand. Metal complexes of LO with Cu(II) and Zn(II) were found to be highly active against S. typhimurium than the complexes of LM.

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Ultramicrocoulometric determination of ammonia in serum, plasma, and blood

A method has been developed for the ultramicrodetermination of ammonia in as little as 0.01 ml of serum, plasma, or blood by coulometric titration with electrogenerated hypobromite using a sensitive amperometric endpoint. The only accurate volumetric measurement required is the pipetting of the sample. The sample is added to a 33-mm microdiffusion cell for 10 min to separate the ammonia; the ammonia is collected in 0.1 ml of 0.0025 M sulfuric acid in the center compartment. The separated ammonia is added to a coulometric generation cell where an excess amount of hypobromite has been generated. The decrease in amperometric current due to the utilization of the hypobromite by the ammonia is taken as a measure of the ammonia content; comparison is made with diffused standards. An optimum pH of 8.6 for the titration has been found to give reproducible results at all levels encountered. One-tenth-milliliter blood samples are routinely analyzed. When elevated ammonia levels are encountered, 0.01-ml samples can be used with accurate results. The time for the analysis is 10–15 min after initiating the diffusion.     

Kinetics of silver nanoparticle growth in aqueous polymer solutions: 1st Nano Update

In this paper we report the effect of poly(vinyl alcohol) (PVA) on the silver nanoparticles formation of different morphologies by using silver nitrate and citric acid as the oxidant and reductant, respectively, for the first time. Our transmission electron microscopy (TEM) results suggest that the presence of PVA has significant impact on the size, shape, and the size distribution of the silver nanoparticles. The reaction follows a zero-order kinetics in [citric acid] as well as in [silver(I)] in the absence and presence of PVA. It was found that PVA and cetyltrimethylammonium bromide (CTAB) concentrations show no significant effects on the rate of CTAB-stabilized silver nanoparticles formation, whereas in presence of PVA, the reaction rate increases with (CTAB). Both spectrophotometric and TEM measurement demonstrated that the orange silver sol consists of aggregates, whereas the purple sol does not contain the aggregated arrangement. On the basis of various observations, the most plausible mechanism has been envisaged.     

Design of novel optically active oligomers consist of units similar to BODIPY molecules

Structural Chemistry - In this study, based on new designed and reported molecules with chemical formula of C13H13B2N, novel electrically and optically active oligomers with different size were...     

All-Optical Multi-Mode Interference Switch Using Non-Linear Directional Coupler as a Passive Phase Shifter

Abstract

This article presents an all-optical multi-mode interference switch in which the non-linear directional coupler is utilized to realize a passive phase shifter. The proposed structure can be used either as a 1 × 2 or a 2 × 2 switch, with two inputs applied simultaneously in the latter case. The operation of the device is mainly based on the phase difference of the inputs of the multi-mode interference section. The beam propagation method is used for the design and simulation of the structure. The simulation results approve the low sensitivity on wavelength and fabrication tolerances. The crosstalk of the structure is equal to ?31.6 dB.     

p‐TSA Catalyzed Synthesis of 2,4,5‐Triarylimidazoles from Ammonium Heptamolybdate Tetrahydrate in TBAI

A one‐pot synthesis of 2,4,5‐trisubstituted imidazoles from 1,2‐diketone or α‐hydroxy ketone, aldehyde and ammonium heptamolybdate tetrahydrate in an inexpensive and readily available ionic liquid, tetrabutylammonium iodide (TBAI) in molten state using catalytic amounts of p‐TSA has been described.     

Highly efficient polymer‐stabilized palladium heterogeneous catalyst: Synthesis,characterization and application for Suzuki–Miyaura and Mizoroki–Heck coupling reactions

A suitable approach to stabilize palladium nanoparticles (Pd NPs), with an average diameter of 3–4 nm, on magnetic polymer is described. A new magnetic polymer containing 4′‐(4‐hydroxyphenyl)‐2,2′:6′,2″‐terpyridine (HPTPy) ligand was prepared by the polymerization of itaconic acid (ITC) as a monomer and trimethylolpropane triacrylate (TMPTA) as a cross‐linker and fully characterized. Pd NPs embedded on the magnetic polymer were successfully applied in Suzuki–Miyaura and Mizoroki–Heck coupling reactions under low palladium loading conditions, and provided the corresponding products with excellent yields (up to 98%) and high catalytic activities (TOF up to 257 hr^?1). Also, the catalyst can be easily separated and reused for at least consecutive five times with a small drop in catalytic activity.     

A new strategy to design a graphene oxide supported palladium complex as a new heterogeneous nanocatalyst and application in carbon–carbon and carbon‐heteroatom cross‐coupling reactions

The palladium nanoparticles were successfully stabilized with an average diameter of 6–7 nm through the coordination of palladium and terpyridine‐based ligands grafted on graphene oxide surface. The graphene oxide supported palladium nanoparticles were thoroughly characterized and applied as an efficient heterogeneous catalyst in carbon–carbon (Suzuki‐Miyaura, Mizoroki‐Heck coupling reactions) and carbon–heteroatom (C‐N and C‐O) bond‐forming reactions. The catalyst was simply recycled from the reaction mixture and was reused consecutive four times with small drop in catalytic activity.