Two novel diorganotin phosphonic diamides: syntheses,crystal structures,spectral properties and in vitro antibacterial studies

Two diorganotin complexes with general formulae SnCl₂(CH₃)₂[C₆H₅P(O)(NHCH(CH₃)₂)₂]₂ ( 1 ) and SnCl₂(CH₃)₂[C₆H₅P(O) (NHC(CH₃)₃)₂] ( 2 ) were prepared by the addition of one equivalent SnCl₂Me₂ to two equivalents of PhP(O)(NHⁱPr)₂ and PhP(O)(NH^tBu)₂, respectively. The compounds were characterized by elemental analysis, IR and multinuclear NMR (¹H, ¹³C, ³¹P and ¹¹⁹Sn) spectroscopy. The crystal structures of the complexes were determined by X‐ray single crystal analysis, which revealed that complex 1 has a distorted octahedral geometry and complex 2 has a distorted trigonal bipyramidal structure with non‐equivalent chlorine atoms. Preliminary antibacterial tests of the compounds against Gram‐positive and ‐negative bacteria were carried out using the filter paper disk method and chloroamphenicol was used as standard for comparison. Copyright © 2010 John Wiley & Sons, Ltd.     

Density-functional calculations of HCN adsorption on the pristine and Si-doped graphynes

Graphyne, a lattice of benzene rings connected by acetylene bonds, is one-atom-thick planar sheet of sp- and sp²-bonded carbons differing from the hybridization of graphene (considered as pure sp²). Here, HCN adsorption on the pristine and Si-doped graphynes was studied using density-functional calculations in terms of geometric, energetic, and electronic properties. It was found that HCN molecule is weakly adsorbed on the pristine graphyne and slightly affects its electronic properties. While, Si-doped graphyne shows high reactivity toward HCN, and, in the most favorable state, the calculated adsorption energy is about ?10.1 kcal/mol. The graphyne, in which sp-carbon was substituted by Si atom, is more favorable for HCN adsorption in comparison with sp²-carbon. It was shown that the electronic properties of Si-doped graphyne are strongly sensitive to the presence of HCN molecule and therefore it may be used in sensor devices.     

Hybrid nanosheets composed of molybdenum disulfide and reduced graphene oxide for enhanced solid phase extraction of Pb(II) and Ni(II)

Microchimica Acta - Non-modified molybdenum disulfide (MoS2) is known to adsorb heavy metal ions. However, in case of very small particle sizes and high dispersibility, ordinary centrifugation and...     

Sulfamic acid heterogenized on functionalized magnetic Fe3O4 nanoparticles with diaminoglyoxime as a green,efficient and reusable catalyst for one‐pot synthesis of substituted pyrroles in aqueous phase

Surface functionalization of magnetic nanoparticles is an elegant way to bridge the gap between heterogeneous and homogeneous catalysis. We have conveniently loaded sulfonic acid groups on amino‐functionalized Fe₃O₄ nanoparticles affording sulfamic acid‐functionalized magnetic Fe₃O₄ nanoparticles (MNPs/DAG‐SO₃H) as an active and stable magnetically separable acidic nanocatalyst, which was characterized using X‐ray diffraction, Fourier transform infrared and energy‐dispersive X‐ray spectroscopies, scanning and transmission electron microscopies, vibrating sample magnetometry and elemental analysis. The catalytic activity of MNPs/DAG‐SO₃H was probed through one‐pot synthesis of N‐substituted pyrroles from γ‐diketones and primary amines in aqueous phase at room temperature. The heterogeneous catalyst could be recovered easily by applying an external magnet device and reused many times without significant loss of its catalytic activity. Copyright © 2014 John Wiley & Sons, Ltd.     

A modified and green methodology for preparation of polysubstituted furans

In this study, we introduced a very simple, one‐pot and green methodology for preparation of polysubstituted furans by reaction of aromatic aldehydes, DMAD, and alkylisocyanides in water and at room temperature. © 2005 Wiley Periodicals, Inc. 16:259–262, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20086     

Selective and Convenient Protection of Aldehydes as Azines under Solvent‐Free Conditions

Aldehydes can be easily protected as azines in the presence of hydrazine monohydrochloride and ferric chloride under solvent‐free conditions. The major advantages of this method are: operational simplicity, ready availability, selectivity, general applicability, mild reaction conditions with low cost of the reactants, short reaction times and excellent yields.     

An efficient synthesis of substituted alkyl acrylates using α-keto amides

The addition of α-keto amides as a NH-acid to alkyl propiolates and dialkyl acetylenedicarboxylates in the presence of a catalytic amount of triphenylphosphine gives the corresponding substituted alkyl acrylates.     

Reaction kinetics investigation of 1‐fluoro‐2,4‐dinitrobenzene with substituted anilines in ethyl acetate–methanol mixtures using linear and nonlinear free energy relationships

Aromatic nucleophilic substitution reaction of 1‐fluoro‐2,4‐dinitrobenzene with para‐substituted and meta‐substituted anilines was kinetically investigated in the mixtures of ethyl acetate and methanol at room temperature. The correlation of second‐order rate coefficients with Hammett's substituent constants yields a fairly linear straight line with negative slope in different mole fractions of ethyl acetate–methanol mixtures. The measured rate coefficients of the reaction demonstrated a dramatic variation in ethyl acetate–methanol mixtures with the increasing mole fraction of ethyl acetate. Linear free energy relationship (LFER) investigations confirm that polarity has a major effect on the reaction rate whereas the hydrogen‐bonding ability of the media has a slight effect on it. Nonlinear free energy relationship based on preferential solvation hypothesis showed differences between the microsphere solvation of the solute and the bulk composition of the solvents, and non‐ideal behavior is observed in the trend of the rate coefficients, which cover the LFER results. Copyright © 2011 John Wiley & Sons, Ltd.