Preparation of gold nanoislands on various functionalized polymer-modified glass and ITO for electrochemical characterization of monolayer assembly of alkanethiols

Nanometer dimension of citrate-capped gold nanoparticles can be firmly bound with various functionalized polymer-modified glass plate and indium tin oxide (ITO) substrates. Herein we report 3-aminopropyltriethoxysilane, polyvinyl pyridine, polyethylene imines, etc. as binding agents to modify these substrates to stabilize the charged colloidal gold nanoparticles through electrostatic stabilization of gold nanoparticles. When gold nanoparticles pretreated substrate are exposed into the seeding growth solution, the preadsorbed gold nanoparticles grow further and then form nanoislands of gold on glass and ITO substrates. The formation of nanoislands on microscope glass slide and ITO was monitored with UV-visible spectroscopy, cyclic voltammetry, and atomic force microscopy methods. The gold nanoislands and gold nanoparticles pretreated substrates can be used as platform to study the self-assembling behavior of long chain alkanethiols such as C₁₂SH, C₁₆SH, and C₁₈SH. The binding, coverage, and electron transfer characteristics of monolayer assembly on modified gold nanoisland and nanoparticles modified substrates are studied using electrochemical studies. The gold substrates can be prepared by this method, which is simple and reproducible and can be applied to various sensor and electrocatalytic applications.     

Angular distributions for target residues in reactions of 14N and 12C with 115In

Mechanisms of the reactions of ¹²C and ¹⁴N with ¹¹⁵In have been investigated by measuring the angular distributions of the target residues. Various possible transfer mechanisms are discussed with the help of kinematic analysis and a semiclassical transfer model. Interesting secondary (or tertiary) peaks are seen near 90 in the angular distributions for most target residues.     

Effect of load in scratch experiments on soda lime silica glass

Today the technological applications of glass span from everyday life to many advanced areas. These advanced applications require very accurate grinding and polishing that involve controlled removal of glass to achieve micron or even sub-micron surface finish. The major bottleneck in this connection is that the material removal mechanisms during such processes are yet to be fully understood. Since grinding involves many single pass scratch processes happening simultaneously, to develop better understanding about the effect of the normal load in affecting the material removal mechanisms; a number of single pass scratch experiments were conducted on a commercially available soda lime silica glass as a function of various normal loads (2–15 N) at a constant scratch speed of 100 μm.s^? 1. The results showed that the tribological properties, the severity and the spatial density of damage evolution were sensitive to the applied normal loads and the resultant tensile as well as shear stresses. Extensive optical and scanning electron photomicrography of the surface and sub-surface deformation zones proved the existence of three distinct deformation zones in the immediate vicinity of the scratch grooves and led to the development of a qualitative model of the material removal mechanisms.     

Mediator-free simultaneous determination of acetaminophen and caffeine using a glassy carbon electrode modified with a nanotubular clay

Microchimica Acta - The authors describe a voltammetric method for the simultaneous determination of acetaminophen (ACOP) and caffeine (CAF) using a glassy carbon electrode modified with a...     

Cobalt‐Catalyzed Cyclization of N‐Methoxy Benzamides with Alkynes using an Internal Oxidant through C−H/N−O Bond Activation

The cyclization of substituted N‐methoxy benzamides with alkynes in the presence of an easily affordable cobalt complex and NaOAc provides isoquinolone derivatives in good to excellent yields. The cyclization reaction is compatible with a range of functional group‐substituted benzamides, as well as ester‐ and alcohol‐substituted alkynes. The cobalt complex [Co^IIICp*(OR)₂] (R=Me or Ac) serves as an efficient catalyst for the cyclization reaction. Later, isoquinolone derivatives were converted into 1‐chloro and 1‐bromo substituted isoquinoline derivatives in excellent yields in the presence of POCl₃ or PBr₃.     

Clinical Grade iPS Cells: Need for Versatile Small Molecules and Optimal Cell Sources

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Triazine‐based Organic Polymer‐catalysed Conversion of Epoxide to Cyclic Carbonate under Ambient CO2 Pressure

In this work we have achieved epoxide to cyclic carbonate conversion using a metal‐free polymeric catalyst under ambient CO₂ pressure (1.02 atm) using a balloon setup. The triazine containing polymer (CYA‐ANIS) was prepared from cyanuric chloride (CYA?Cl) and o‐dianisidine (ANIS) in anhydrous DMF as solvent by refluxing under the N₂ gas environment. The presence of triazine and amine functional groups in the polymer results in the adsorption of CO₂ up to 7 cc/g at 273 K. This inspired us to utilize the polymer for the conversion of a series of functionalised epoxides into their corresponding cyclic carbonates in the presence of tetrabutyl ammonium iodide (TBAI) as co‐catalyst. The product has wide range of applications like solvent in lithium ion battery, precursor for polycarbonate, etc. The catalyst was efficient for the conversion of different mono and di‐epoxides into their corresponding cyclic carbonates under atmospheric pressure in the presence of TBAI as co‐catalyst. The study indicates that epoxide attached with electron withdrawing groups (like, CH₂Cl, glycidyl ether, etc.) displayed better conversion compared to simple alkane chain attached epoxides. This is mainly due to the stabilization of electron rich intermediates produced during the reaction (e. g. epoxide ring opening or CO₂ incorporation into the halo‐alkoxide anion). This catalyst mixture was capable to maintain its reactivity up to five cycles without losing its activity. Post catalytic characterization clearly supports the heterogeneous and recyclable nature of the catalyst.     

Enhancement of in vitro fungicidal activity of fuberidazole to Botrytis cinerea by cucurbiturils

The host–guest interaction of fuberidazole (FBZ) fungicide with cucurbituril (CB) macromolecules was characterized in pure water using UV–vis spectrophotometric and NMR techniques. The in vitro applications (at pH 5.5 in pure water) of host–guest complexes were conducted against Botrytis cinerea. While addition of CB5 to FBZ had no significant effect in vitro, mixing CB7 or CB8 with FBZ in a 1:2 ratio improved fungal growth inhibition at least threefold, when compared to the corresponding concentration of the unbound fungicide molecules. Empty CB hosts were completely inactive. Furthermore, the inhibitory activity to B. cinerea was relatively maintained down to a concentration of 5:10 μM of the CB7/8@FBZ complexes, relative to any of controls. Complexation by CB7/8 further improved the photostability of the fungicides with photostabilization factors of 7 and 3, respectively. CB7/8 bound the protonated forms of these guests very strongly but their neutral forms were significantly weaker, which reflects a complexation-induced increase of their pK _a values by 3.8 units with CB7 and 1.4 units with CB8. The present investigation constitutes an innovative, nonclassical, approach to enhance fungicides efficacy utilizing macromolecules with a potential application in crop protection technology.