A novel Schiff-base ligand (L: 2-[(4-chloro-2-oxo-2H-chromen-3-ylmethylene)-amino] propionic acid) was prepared from the reaction of 4-chloro3-formylcoumarin and alanine amino acid. Copper (II) complex was synthesized from the reaction of the ligand with Cu (OAc)2. H2O in ethanol. The ligand and its metal complex were characterized by elemental analysis (CHN), ICP, thermal analysis (TGA), Fouri...

the acetylation of various alcohols and phenols was performed successfully using acetic anhydride in the presence of citric acid coated magnetite nanoparticles as catalyst under solvent-free condition and at 45 °c. the catalyst showed high thermal stability and was recovered and reused at least 5 times without any considerable loss of activity. the present process is environmentally benign and ...

A series of unsymmetric salen ligands derived from 1,2-diaminocyclohexane bearing an appended Lewis base on the three-position of one aromatic ring were synthesized by the reaction of various functional salicyaldehydes with the condensation product of 1,2-diaminocyclohexane mono(hydrogen chloride) and 3,5-di-tert-butylsalicylaldehyde. These ligands in conjunction with Ti(O(i)Pr)(4) exhibited ex...

ess the relationship between umbilical cord blood gases at birth and morphology of umbilical cord, in a prospective study of 200 consecutive term delivery, we investigated the relationship between umbilical cord morphology characteristics (umbilical crd length, number of vascular coil, coiling index) and color of amniotic fluid and umbilical vessel blood gases. statistically significant linear ...

A two-step reaction mechanism (catalyzed alternatively by acid and base) with partial proton shuttles and charge redistributions promoted by short strong H bonds (SSHBs) (playing a dual role as an amphi-acid/base catalyst) is proposed to explain the enormous rate enhancement observed in enzymatic reactions involving carbanion intermediates. The SSHBs in the two-step reactions are found to be re...

Hydrotalcite like precursors containing Pd–Mg–Al with varying molar ratios, (Pd + Mg)/Al ≈ 3 and Mg/Pd ≈ 750 to 35, were prepared by coprecipitation of metal nitrates at constant pH. Characterization of samples as synthesized and their calcined products by elemental analyses, powder XRD, TG–DTA, FT–IR spectroscopy, TPR and N2 physisorption indicated a well crystalline hydrotalcite like structur...

Hydrogenation of benzoic acid using monoand bimetallic catalyst of Ru, Pd, Co, and Re yielded different products. It was observed that 5% Ru/C was an active catalyst for hydrogenation of both aromatic ring and carboxylic group, while Pd/C catalyst hydrogenated only aromatic ring. Ru-Sn/Al2O3 is a chemoselective catalyst for hydrogenation of –COOH group of benzoic acid.

Xylanases from family 10 glycanases contain three conserved histidine residues in their active site. The role of H86 in the structure-function of xylanase A from Streptomyces lividans (XlnA) was studied by site-directed mutagenesis. Six mutant proteins (H86A/E/F/K/Q/W) were produced, purified and characterized. The six mutations reduced the affinity of XlnA towards xylan without having any majo...