Journal of Physical and Theoretical Chemistry
Volume:2 Issue: 3, Autumn 2005

Reactions of Meldrum's acid and its derivatives in view of their application in synthesis of diaminofurans,ketenimines, amidoesters, triamides, and diionic compounds, observed during the last decade in our laboratory,are reviewed.

A series of sorbents containing various amounts of borate groups were prepared by chemical immobilization ofP-aminoethylphenylboric acid on a copolymer- treated organosilane spacer glass plates. It was found thatbaker's yeast cells selectively adhered to these supports. Yeast cells stained with procion red HE-3B formeddenser and more stable layer on the copolymer-grafted supports compared onto supports modified withphenylboric acid via a organosilane spacer. Adhesion of yeast cells to boronate-containing polymer fixed onsolid support in presence of different concentration of fructose, a sugar with high affinity to boronates, wasstudied.

The interaction of dopamine and cysteine for formation of 5-S-cysteinyldopamine are investigated at theHartree-Fock level theory. The structural and vibrational properties of 5-S-cysteinyldopamine are studiedat level of HF/6-31G*.Interaction energy ( AE) is calculated -771.6923 Kcal/mol Rotational energy andthermodynamic parameters around two bond have been determined using HF/3-21G. Changes of entropyduring rotation around of two atom is from 119.252 to 133.016 cal/mol.K and in the case of anotherbond is from 111.439 to 123.55 cal/mol.K . Vibrational frequencies and isotropic shifts are interpreted

The conformational behavior of monosubstituted tri-methylsilyle ethynyl Derivative of Cal ix[4]arene as a newgeneration of Caliarene was compared with tetra alkylated calyx[4]arene. The most important conformationalphenomena in these compounds which are pinched cone interconversion process were done by semi-empiricalmethod and ab initio calculations with Gaussian 98w programming.

The internal structure of DNA-CTAB and DNA-DDAB is investigated by a Small Angel X- ray Scattering(SAXS) instrument. Hexagonal packing of DNA was observed for DNA complex with CTAB, and for DDABcomplex is observed lamellar structure. Variations in the internal spacing and degree of long-range ordering aredependent on both surfactant type and concentrations of added salt. When we increased the amount of salt intoour complex we observed that the d spacing (d= 211/q) are increased.

The IP3R calcium release channel has been simulated using a stochastic simulation algorithm (SSA;Gillespie algorithm) and De young-Keiser model. A set of different concentration for Cat' and IP3 havebeen used. Considering the Number of molecules in each state, a non linear behavior of the system can beseen clearly. The inhibiting role of the Ca+2 on the open state (X110) has been studied. The degree ofinhibition may depend on the IP3 concentration. Different levels of inhibition have seen in differentinhibited states. Using the Gillespie algorithm, the frequency graphs for each set of Ca+2 and IP3concentrations and in different time domains can be achieved. The probability of open channel increaseswith going from small time domain to large time domain. A good consistency can be inferred comparingwith different results from the past studies (Both in theoretical and experimental studies).A reaction patternin fast time domain has seen, too.

Using Solvent Evaporating and Atomic Emission Spectrophotometric methods, the solubility of Ba (NO3 )2 inwater at 25.0 ° C was determined. Activity coefficients, f+ and f_ of Bat) and N0i(aq) ions in the saturatedsolution at 25.0 ° C were estimated upon the extended Debye —Hiickel theory and then, the constantK'sp =[Ba2+1f+ [NO-3 ]2 f 2 was evaluated. Comparing the value of thermodynamic solubility product constant,Ksp(th) ,of Barium Nitrate, Ks") =exp (—AG ° / RI) , to the value of K'sp revealed a great difference.The difference has satisfactorily been explained using a combination of Debye-Hackel theory and ionassociationtheory.