Effect of precursor pH on structural,magnetic and catalytic properties of CoFe2O4@SiO2 green nanocatalyst

Research on Chemical Intermediates - Cobalt ferrite is a promising material for many therapeutic applications, photo-catalysis, gas detectors, high-density data storage, etc. Optimization of...     

Sensing of Phosphates by Using Luminescent EuIII and TbIII Complexes: Application to the Microalgal Cell Chlorella vulgaris

Phenanthroline‐based chiral ligands L¹ and L² as well as the corresponding Eu^III and Tb^III complexes were synthesized and characterized. The coordination compounds show red and green emission, which was explored for the sensing of a series of anions such as F^?, Cl^?, Br^?, I^?, NO₃^?, NO₂^?, HPO₄^2?, HSO₄^?, CH₃COO^?, and HCO₃^?. Among the anions, HPO₄^2? exhibited a strong response in the emission property of both europium(III) and terbium(III) complexes. The complexes showed interactions with the nucleoside phosphates adenosine triphosphate (ATP), adenosine diphosphate (ADP), and adenosine monophosphate (AMP). Owing to this recognition, these complexes have been applied as staining agents in the microalgal cell Chlorella vulgaris. The stained microalgal cells were monitored through fluorescence microscopy and scanning electron microscopy. Initially, the complexes bind to the outer cell wall and then enter the cell wall through holes in which they probably bind to phospholipids. This leads to a quenching of the luminescence properties.     

Plasmon‐Enhanced Photocurrent Generation from Click‐Chemically Modified Graphene

The visible‐light response of Au nanoparticles (AuNPs) assembled on rGO through different molecular bridges was investigated by transient photocurrent generation. We prepared rGO with two self‐assembled monolayers (SAMs), one linear and the other with aromatic triazoles through a click cycloaddition reaction. A fivefold photocurrent enhancement was observed for triazole linkers over the aminopropyltrimethoxysilane (APTMS) linker. Cyclic voltammetry (CV) and impedance measurements also suggest fast electron transfer on account of the low resistance offered by the click‐modified rGO surface whereby introduction of triazoles offers the efficient bridge between the donor AuNPs and acceptor rGO.     

Asymmetric Gold‐Catalyzed Lactonizations in Water at Room Temperature

Asymmetric gold‐catalyzed hydrocarboxylations are reported that show broad substrate scope. The hydrophobic effect associated with in situ‐formed aqueous nanomicelles gives good to excellent ee’s of product lactones. In‐flask product isolation, along with the recycling of the catalyst and the reaction medium, are combined to arrive at an especially environmentally friendly process.     

para-Selective Arylation of Arenes: A Direct Route to Biaryls by Norbornene Relay Palladation

Biaryl compounds are extremely important structural motifs in natural products, biologically active components and pharmaceuticals. Selective synthesis of biaryls by distinguishing the subtle reactivity difference of distal arene C−H bonds are significantly challenging. Herein, we describe para-selective C−H arylation, which is acheived by a unique combination of a meta-directing group and norbornene as a transient mediator. Upon direct meta-C−H palladation, one-bond relay palladation occurs in presence of norbornene and subsequently para-C−H arylation is achieved for sulfonates, phosphonates and phenols bearing 2,6-disubstitution patterns. The protocol is amenable to electron-deficient aryl iodides. Multisubstituted arenes and phenols are obtained by postsynthetic modification of the products. The protocol allows the synthesis of hexa-substituted benzene by sequential selective distal C−H functionalization.     

N-donor stabilized complexes of nickel(II) diphenyldithiophosphates: single-crystal X-ray,HSA and computational analysis

Transition Metal Chemistry - Nickel(II) complexes with octahedral coordination stabilized by N-donor ligands corresponds to [{(ArO)2PS2}2Ni·L2] [Ar = 4-(C2H5)C6H4 (3), and...     

One-pot green synthesis of novel 5,10-dihydro-1H-pyrazolo[1,2-b]phthalazine derivatives with eco-friendly biodegradable eggshell powder as efficacious catalyst

Research on Chemical Intermediates - An eco-friendly and efficient green protocol is developed for the synthesis of sixteen pyrazolo-phthalazine derivatives (5a–p) by using...     

The integrable Boussinesq equation and it’s breather,lump and soliton solutions

The fourth-order nonlinear Boussinesq water wave equation, which explains the propagation of long waves in shallow water, is explored in this article. We used the Lie symmetry approach to analyze the Lie symmetries and vector fields. Then, by using similarity variables, we obtained the symmetry reductions and soliton wave solutions. In addition, the Kudryashov method and its modification are used to explore the bright and singular solitons while the Hirota bilinear method is effectively used to obtain a form of breather and lump wave solutions. The physical explanation of the extracted solutions was shown with the free choice of different parameters by depicting some 2-D, 3-D, and their corresponding contour plots.

     

Triazoles as complexing agents: Synthesis and structural studies of some bivalent metal ion complexes with Bi- and tridentate ligands

Summary Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes of 4-amino-5-mercapto-3-trifluoromethyl-s-triazole (AMTT) and 5-mercapto-4-salicylideneamino-3-trifluoromethyl-s-triazole (MSTT) have been synthesized and characterized on the basis of elemental analyses, magnetic measurements, infrared and electronic spectral data. The ligandsAMTT andMSTT were characterized by elemental analyses, infrared and¹H NMR spectral studies.AMTT, involving N and S as donor atoms, andMSTT, involving N, O and S as donor atoms, act as bi- and tridentate ligands, respectively. The geometry of the complexes has been assigned on the basis of magnetic and electronic spectral data. EPR parameters for copper (II) complexes have been calculated. Thermal stabilities of the complexes are also reported. Due to insolubility in water and common organic solvents and infusibility at higher temperatures, all the complexes are thought to be polymeric in nature.

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Triazole als Komplexierungs-Agentien: Synthese und Strukturuntersuchungen an einigen bivalenten Metallionenkomplexen mit zwei- und dreizähnigen Liganden

Zusammenfassung Es wurden Co(II)-, Ni(II)-, Cu(II)-, Zn(II)- und Cd(II)-Komplexe von 4-Amino-5-mercapto-3-trifluormethyl-s-triazol (AMTT) und 5-Mercapto-4-salizylidenamino-3-trifluormethyl-s-triazol (MSTT) hergestellt und mittels Elementaranalyse, magnetischen Messungen, Infrarot- und Elektronenspektroskopie charakterisiert. Die LigandenAMTT undMSTT wurden elementaranalytisch und spektroskopisch (IR und¹H-NMR) charakterisiert.AMT wirkt über die N-und S-Donoratome als zweizähniger Ligand,MSTT über N, O und S als dreizähniger Ligand. Die Geometrie der Komplexe wurde auf der Basis von magnetischen und elektronenspektroskopischen Daten zugeordnet. Für die Cu(II)-Komplexe wurden die EPR-Parameter berechnet. Die thermischen Stabilitäten der Komplexe wurde ebenfalls untersucht. Wegen ihrer Unlöslichkeit in Wasser und gängigen organischen Lösungsmitteln und der Unschmelzbarkeit bei höheren Temperaturen wird eine polymere Natur der Komplexe angenommen.