Iranian Journal of Chemistry and Chemical Engineering
Volume:13 Issue: 1, May-Jun 1994

3-(2-Furanyl)-2- Propenoic acid has been used to prepare a new series of organotin complexes of general formula R3SnL (R=Me, Et, n-Bu, Ph and Cy) and R2SnL2 (R=Me and n-Bu). These complexes have been characterized by elemental analyses, IR, 1H-NMR, MASS and Mössbaure spectroscopy.

The 2-(methylamino) pyridine, L, reacts with CuCl in THF to give hexameric copper (I) complex, [CuCl(L)]6. The molecular structure has been determined by using single – crystal X – ray diffraction method. The complex crystallizes in the monoclinic space group P21/n with four molecules per unit cell. The unit cell dimensions are a=8.3495(15), b=15.622(6), and c=17.030(4)Å with b=98.55(2)°. The final R value is 0.062 for 4261 reflections measured. Coordination number around Cu(1) and Cu(3) is four (nearly tetrahedral), but around Cu(2) is three (nearly trigonal). The Cu(2) – Cu(3) bond distance is 2.682(2) Å.

Results of the bromination and dehydrobromination of several angular methylated decalindiones are described. The key reaction, base-induced cyclization of the monobromo keto ester (3), and the dibromo ketone (4), leads to the formation of tricyclic systems (6) and (9) respectively.

X-Ray Photoelectron and electron energy loss spectroscopic (XPS-EELS) studies reveal that the following species are present when a mixture of CO2 and water vapour is exposed to the clean Mg(100) surface at 116K: CO3(a), C(a), CH(a), OH(a). The reactive chemisorption of CO2 and H2O vapour coadsorbed on a Mg surface leads to the formation of CH bond. Increasing the temperature to 400K shows the peaks in the C(1s) region of the spectrum disappears suggesting the CH containing species are not stable at 400K.

The Surface-enhanced Raman scattering (SERS) spectra of maleic (cis; 2- butaneoic acid) and fumaric (trans; 2-butaneoic acid) and fumaric (trans; 2-butaneoic acid) acids adsorbed on aqueous silver sol particles are reported. These two acids form two groups of isomers which differ only in the relative positions of the two carboxylate groups.

The thermal denaturation of adenosine deaminase (ADA) has been investigated in the presence of sodium n-dodecyl sulphate (SDS) over the temperature range of (293-363K) in 2.5mM phosphate buffer, pH 6.4 by temperature scanning spectroscopy. The interaction of SDS caused the folding of adenosine deaminase resulting in a decrease of TH (temperature of minimum solubility), TS (temperature of maximum stability), (intermolecular force between hydrophobic parts of adenosine deaminase with water) and other corresponding thermodynamic parameters. The folding of adenosine deaminase by SDS, induced minimum solubility at lower temperatures indicating enhanced a polar interactions in the interior phase resulting in a lower value for TH. In contrast the interaction of ADA with dodecyl trimethylammonium bromide (DTAB) led to the unfolding of the enzyme and a higher value of TH.

Even though the use of enzymes as useful analytical reagents when immobilized onto a transducer such as an electrochemical device has been reported in the literature for nearly two decades, the direct, i.e. unmediated electrochemistry of enzymes is, nevertheless, a rather recent development. Efforts will be made to introduce the fundamental basis for protein-surface interactions with emphasis on the powerful technique of cyclic voltammetry. The experimental schemes and ample examplex as performed in our laboratur will also be presented to illustrate the kinetic and thermodynamic information acquired based on such enzymatic systems. It is believed that further acquisition of knowledge in the field combined with findings from other complementary disciplines such as modeling and simulation, instrumental computerization and miniaturisathion, and on-line adaptability will ultimately pave the way toward the universal acceptance of biosensors and actuators for chemical analysis.

The efficacy of activation methods and coupling were studied in the context of performance in batch and fixed bed binding experiments utilizing cell culture fluids or blood plasma as feedstock. Conclusions were drawn regarding selection of solid phase according to pore size, rigidity, pH stability, chemistry of derivation and activation, and gross concentrathion of immobilized ligand required for optimal performance in analytical and preparative fractionation of complex feedstreams.