Journal of the Mexican Chemical Society

http://www.scielo.org.mx/scielo.php?script=sci_serial&pid=1870-249X&lng=en

List of Papers (Total 213)

Ab Initio Study and Hydrogen Bonding Calculations of Nitrogen and Carbon Chemical Shifts in Serine-Water Complexes

The hydrogen bonding (HB) effects on the NMR shielding of selected atoms in a few Ser-nH2O complexes have been investigated with quantum mechanical calculations of the 15N and 13C tensors. Interaction with water molecules causes important changes in geometry and electronic structure of serine. Chemical shift calculations, geometry optimization and energies have been performed...

Microwave-assisted Synthesis, Crystal and Molecular Structure, and DFT Study of 1-(2-aminoethyl)-2-imidazolidinethione

A fast microwave-assisted procedure for synthesizing 1-(2-aminoethyl)-2-imidazolidinethione (1) is described. The crystal and molecular structure was determined. The combination of an X-ray crystallographic study and theoretical calculations (DFT) provided insight into the understanding of the high performance of this compound as low toxicity corrosion inhibitor.

Economics on the Use of Oxygenates

The cost of oxygenating gasoline is analyzed considering spot prices prevailing in the American Coast of the Gulf of Mexico from May to July 2003. We found that it is cheaper to oxygenate gasoline using MTBE rather than EtOH, when unsubsidized EtOH prices are considered. Refineries in countries no subsidizing EtOH, having fluid catalytic cracking units, will find advantageous to...

Exploring the Liquefied Petroleum Gas - Ozone Relation in Guadalajara, Mexico, by Smog Chamber Experiments

It has been hypothesized that liquefied petroleum gas (LPG) emissions can increase substantially the formation of ozone (O3) in the ambient air. We tested experimentally such hypothesis in Guadalajara's downtown by captive-air irradiation (CAI) techniques. During November 1997-January, 1998, morning ambient air samples were confined in outdoor smog chambers and subjected to the...

Chemical Constituents of Senecio procumbens

A chemical study of Senecio procumbens afforded the 12-membered macrocyclic diester pyrrolizidine alkaloids senecionine (1), senecivernine (2), retrorsine (3) and their N-oxides, together with 132-hydroxyphaeophytin a (4), caffeic acid methyl ester (5), and cacticin (6). The identification of these compounds was accomplished by comparison of their spectral features with those...

Determination of PCBs in Transformers Oil Using Gas Chromatography with Mass Spectroscopy and Aroclors (A1254:A1260)

The current study shows a calibration method in gas chromatography (GC) with detection by mass spectrometry (MS) to quantify polychlorinated biphenyls (PCBs) present in transformer oils. The calibration was carried out with a secondary standard composed of a mixture of Aroclors (A1254:A1260), in one to one proportion and a reference standard (1,3,5-trichlorobenzene). This last...

1-Acetylvinyl Acrylates: New Captodative Olefins Bearing an Internal Probe for the Evaluation of the Relative Reactivity of Captodative against Electron-Deficient Double Bonds in Diels-Alder and Friedel-Crafts Reactions

The captodative olefins 1-acetylvinyl esters of methacrylic and trans-crotonic acids, 3a and 3b, have been prepared. The presence of a second double bond in the molecule, acting as an internal probe, allowed us to compare their relative reactivity in Diels-Alder and Friedel-Crafts reactions. The reactivity was evaluated with cyclopentadiene (6) as diene in Diels-Alder...

Dimeric Boronates Derived from the Reaction of Schiff Bases and Boronic Acids

The one-pot synthesis of dimeric boron complexes is reported. The compounds were obtained by reaction of Schiff bases (tridentate ligands) with trans-β-phenylvinylboronic acid, 3-thiopheneboronic acid and methylboronic acid. Building of the dimeric structures is favored by the presence of intramolecular N→B coordination bonds, resulting in the formation of ten-membered ring...

Solid-Phase Organic Synthesis of Sensing Sorbent Materials for Copper and Lead Recovery

The synthesis of sorption materials for retention and/or preconcentration of species of clinical and environmental interest, such as metal ions, is an important area of contemporary research. We report herein the synthesis of different solid supports of anthracene-phosphine sulfide for Cu(II) and Pb(II) preconcentration. Sensing properties of these materials were also evaluated...

Clay and Refractory Materials Slurries in Inductively Coupled Plasma Optical Emission Spectrometry: Effects of Mechanochemical Synthesis on Emission Intensities of Analytes

The developed work investigated the application of mechanochemical synthesis for promoting reactions in the samples and for synthesizing new compounds for increment of emission intensities of analytes in clays and refractory materials slurries in inductively coupled plasma optical emission spectrometry with axial viewing. The hypothesis is that it is possible to generate more...

Bonding Interactions of Metal Clusters [Mn (M= Cu, Ag, Au; n=1-4)] with Ammonia: Are the Metal Clusters Adequate as a Model of Surfaces?

Density Functional (B3LYP/LANL2DZ) calculations for ammonia metal clusters were done in order to obtain bond lengths, M-N stretching vibrational modes, binding energies, Mulliken atomic charges and adiabatic ionization potentials. The results indicate that copper atom forms stronger bonds with ammonia than silver or gold. The bond interaction between Agn and ammonia is the...

Electrochemical and Atomic Force Microscopy Investigations of New Materials from N-Trifluoromethanesulfonyl-1-azahexa-1,3,5-trienes Derivatives

Thin films have been created on the surface of highly oriented pyrolytic graphite electrodes from chemically synthesized π-donor species by using the cyclic voltammetry technique and in situ electrochemistry-atomic force microscopy. Results indicate that it is possible to form new compounds called molecular materials from the coupling of electro-oxidized N-trifluoro...

Highly Efficient Inversion of the C-3 Configuration in 1,2-0-Isopropylidenefuranose Derivatives by an Adapted Swern Oxidation/Sodium Borohydride Reduction Protocol in One Pot

One pot Swern oxidation-sodium borohydride reduction of 1,2-O-isopropylidenefuranose derivatives having the D-gluco or D-xylo configurations led to the corresponding stereoisomers resulting from the stereoselective inversion of C-3. This method is a simple adaptation to the traditional procedure that consists in quenching the Swern oxidation at -60 °C with a mixture of H2O/EtOH...