A specific and sensitive optical chemical sensor (optode) was fabricated for the determination of mercury ions. The optode was prepared by recently synthesized composites, 5, 10, 15, 20-tetrakis (4-hydroxyphenyl) porphyrin (THPP) that stabilized with graphene oxide nanosheets. The graphene oxide–porphyrin composites were synthesized and characterized by field emission scanning electron microscopy (FE-SEM), UV-Vis and Fourier transform infrared (FT-IR) spectroscopic techniques. By interacting the mercury ions and the membrane phase, Hg2+-ionophore complex forms and causes a change in the absorbance of the sensor. A decrease in absorption of the membrane at 426 nm could be used as a suitable wavelength for quantitative determination of Hg (II). The various experimental parameters such as pH of aqueous solution of Hg (II) and content of the THPP as well as the grapheme oxide have been optimized. This optode exhibits a linear range of 6.0×10-5 to 6.0×10-9 mol.L-1 Hg(II) with a detection limit of 3.2×10−9 mol.L−1 and a response time of ∼210 s. Performance characteristics of the sensor evaluated such as good reversibility, selectivity, wide dynamic range, long life span, and high reproducibility. The optical sensor was successfully applied to determination of Hg (II) in water samples.

We present a combined computational and experimental study of the possible conformations adopted by a ditopic Schiff base ligand based on triptycene. We have performed DFT calculations on a Y-shaped Schiff base ligand derived from the condensation of 2,6-diaminotriptycene and 2 hydroxybenzaldehyde to obtain the relative energies of their conformers anti-s-cis, syn and anti-s-trans. Since these conformations are practically isoenergetic, interconversions of conformers proceed by rotation about C-N single bonds. NMR spectroscopy shows the presence in solution of the syn conformer, which is stable at room temperature on the NMR time scale.

We synthesized magnetic ZnFe2O4 nanoparticles via one pot solvent free microwave assisted technique. Iron (III) nitrate nonahydrate and zinc nitrate hexahydrate as reactants were crushed in the presence of reactive reagents. Then, the prepared mixture was transferred into a domestic microwave oven with the power of 900 W for 20 minutes. Finally, the resulting compound was collected, washed several times with ethanol, dried at 80 °C for 24 h and analyzed. The constructed nano-sized zinc ferrite was characterized using powder x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and energy dispersion of x-ray spectrometry (EDX). This technique is a simple, fast, environmental friendly and can draw a usable viewpoint for the synthesis of nanomaterials. The ability of the prepared product was studied on the removal of organic pollutant (Congo Red) from aqueous solution through adsorption mechanism.

The synthesis of a new asymmetric ligand (E)-4-bromo-2-(((2-((5-bromo-2-hydroxybenzyl)(methyl)amino)ethyl)imino)methyl)phenol, which was conceived to model the asymmetry in the active site of peroxidase/catalase mimics, is reported. The new synthetic route involves seven steps: 1) obtention of phthalimido-acetal; 2) Acetal deprotection; 3) Synthesis of the salicylamine; 4) Obtention of the benzoxacine; 5) Reduction of the benzoxacine with NaBH3CN; 6) Reduction with hydrazine to form salycilamine; 7) Synthesis of the final ligand by condensation of salicylamine with salycilaldehyde. All organic products were characterised by microanalysis and 1H NMR, IR and mass spectroscopies.

Calcium oxide was found efficient solid base catalyst for synthesis of chalcone under microwave condition. We employed this method for synthesis of various chalcone from various substituted ketone and aldehyde including o-hydroxy ketone and o-amino ketone. The merits of this methods are inexpensive and easily available solid base catalyst, shorter reaction time, high yield compared to other reported methods, avoid use of toxic regents and solvent free condition, applicable to base sensitive functional group.

Nanoparticles, especially coated or supported magnetic metal part, have emerged as a new class of nanocatalyst. Simple separation of them using an external magnetic field without any filtration is one of the main features for using this type of catalyst. These catalysts showed both high catalytic activity and high degree of chemical stability in various organic solvents.Multi-component reaction (MCRs) has offered many fascinating and challenging transformation in organic synthesis. The atom-economy, convergent character, operational simplicity, structural diversity, and complexity of the molecules are the major advantages associated with multi-component reactions. Besides this multi-component reactions are emerging as a powerful tool in the synthesis of biologically important compounds.Among the heterocycles, functionally substituted 4H-chromenes have received considerable attention in the field of medicinal chemistry because of their wide range of useful biological properties, which include spasmolytic, diuretic, anticoagulant and anticancer activity. Because of their importance, the methods for their synthesis have become a focus of synthetic organic chemist.In continuation of our interest in the application of nanocatalysts in organic synthesis, cellulose -supported metal nanocomposite used as a catalyst for the one-pot and three component synthesis of different 2-amino-4H-chromene derivatives in good to excellent yield under mild conditions. A good correlation between the amount of surface acid sites as well as the surface morphology of the catalysts and the catalytic activity has been observed. This method has been found to be simple and economical, because the solid support could be recycled and reused without significant loss of its catalytic activity.

Chitosan, the N-deacetylation product of chitin has been applied in many fields, due to its biocompatible and biodegradable properties as well as its relative ease to manage compared to its chemical precursor. The control of their chemical and physical properties allows Chitosan derivatives to be used for different biomedical and industrial applications. Degree of deacetylation (DD) and polymer chain length (molecular weight, Mw) can be considered the most important features to determine the physico-chemical properties of these systems and consequently decisive factors to give desired results in formulations and applications.  On the other hand, ureide compounds have been employed in different applications fields such as catalysis involving the selective synthesis of tertiary thiols or medicinal chemistry as glutathione analog. We report here, the synthesis in water of new ureidyl chitosan derivatives and their characterization by NMR techniques both in solution and solid state. Aliphatic and aromatic diisocyanates were used as crosslinking agents to obtain a chitosan network with potential physicochemical properties in gel formation. We thank the AECID (Projects A/023577/09 and A/030422/10) and the 'Junta de Andalucía' (FQM 142 and Project P09-AGR-4597) for financial support.

In situ electrochemical polymerization of an aniline solution containing multi-walled carbon nanotube (MWCNT) of 0.8 wt.% was used to prepare (MWCNT)/polyaniline(PANI) composite films. The electrochemical capacitance performances of these films were investigated with cyclic voltammetry (CV) and ac impedance spectroscopy in 1 M H2SO4 with a three-electrode system. It was found that the MWCNT/PANI films show much higher specific capacitance (SC), better cyclic stability and more promising for applications in supercapacitors than a pure PANI film electrode. The highest specific capacitance value of 500 F g−1 was obtained for the MWCNT/PANI composite film.

The periodic table of the elements (PTE) results essential to understand our nature and place in the whole of beings. The same happens with our food, drugs, materials, etc. A series of questions were asked to introduce PTE and provide answers. The ideas in PTE should be valued by the number of questions that they generate. The PTE was related to electron configurations. The emergence of elements (nucleosynthesis) in physics was explained. The PTE results essential to understand our nature and place in the whole of beings. The same happens with our food, drugs, materials, etc. Schwarz and Rich asked a series of questions (Qs) to introduce PTE and provided answers. The ideas on PTE should be valued by the number of questions that they generate. Q1. Why are the halogens and alkali metals among the first groups treated in chemistry courses? Q2. What is the physical origin of the periods' lengths? Q3. Why are the closed p6 shells of the inert gases more stable than other closed shells, viz. s2 and d10 of chemically active metals (of groups 2, 12 and 10)? Q4. Textbooks give the electron configuration of the transition elements as ns2(n – 1)dG–2 with a few exceptions (G is the number of valence electrons or group number in PTE and n, the main quantum number or period number). Why is transition-metal chemistry practically pure d-atomic orbital (AO) chemistry? Etcetera. A need exists to develop theoretical and experimental research on PTE to understand periodic properties and the periodic law.

Oxindole ring is a privileged scaffold which is present in a number of natural products and molecules with a wide spectrum of pharmacological activities. Spiro oxindoles have attracted great interest as drug candidates and in recent years many synthetic methods for the construction of structurally and functionally diverse systems have appeared in the literature. In this field,  we herein report a new general access to spiro cyclopropyl oxindoles with three-point of diversity: the substitution at the cyclopropane ring, at the aromatic ring and at the nitrogen atom. The synthetic  method is based on a domino Michael Initiated Ring Closure strategy which employs variously substituted vinyl selenones and oxindoles as starting materials. In considerations of the growing interest in green and environmentally benign procedures, the use of water as alternative to standard organic solvents has  been investigated.