Int. J. Mol. Sci., Volume 7, Issue 8 (August 2006) – 5 articles , Pages 230-319

In order to understand the structure-property relationship, SPR, an energy-partitioning quest for the origin of the barrier to the internal rotation of two iso-structuralmolecules, hydrogen peroxide, H₂O₂, and fluorine peroxide, F₂O₂ is performed. Thehydrogen peroxide is an important bio-oxidative compound generated in the body cells tofight infections and is an essential ingredient of our immune system. The fluorine peroxideis its analogue. We have tried to discern the interactions and energetic effects that entail thenonplanar skew conformation as the equilibrium shape of the molecules. The physicalprocess of the dynamics of internal rotation initiates the isomerization reaction and generatesinfinite number of conformations. The decomposed energy components faithfully display thephysical process of skewing and eclipsing as a function of torsional angles and hence aregood descriptors of the process of isomerization reaction of hydrogen peroxide (H₂O₂) anddioxygen difluoride (F₂O₂) associated with the dynamics of internal rotation. It is observedthat the one-center, two-center bonded and nonbonded interaction terms are sharply dividedin two groups. One group of interactions hinders the skewing and favours planar cis/transforms while the other group favours skewing and prefers the gauche conformation of themolecule. The principal energetic effect forcing the molecules into the nonplanar gaucheform is the variation “O–O’ bond energy with torsion in both the molecules. It isdemonstrated that the barrier is not a regional effect rather it is made by the conjoint actionof all one- and two-center bonding and nonbonding interactions comprising the entireframework of the molecule. The present study claims to reveal one amazing feature of non-bonded interactions. Computed results of nonbonding interactions demonstrate that thenature of interaction between two formally positively charged non-bonding H atoms (H^δ+ ----H^δ+ ) is not always repulsive and it is attractive as well; the nature of the non-bondinginteraction between formally negatively charged atom (‘O’) and formally positively charged(‘H’) atom, (O^δ−----H^δ+ ), is not always attractive but repulsive too; it is also demonstrated that the nature of the nonbonding interaction between strongly electronegative atoms, ( F^δ−-- --F^δ−), is not always repulsive and it may be attractive as well. Full article

Superparamagnetic polymers (SPMP) microbead was an excellent form fornanosized magnetic particles less than 10nm to realize their potential applications in manyfields. We developed a novel modified suspension polymerization method for the productionof superparamagnetic poly (methacrylate divinylbenzene) (PMA-DVB) microbeads, withamino groups on their surface after simple modifications. We applied these SPMPmicrobeads to establish a sandwich enzyme chemiluminence immuno (ECLIA) procedure ofdetecting the free hCGβ in serum. It was proved to a better method compared to the ELISA,since it need half of the sample volume, simpler protocols, and the time it need wasshortened from 2 hours to 1 hour. The detection limit was 0.22 mIU•m^-1, one order lowerthan the ELISA assay. Its linear range was between 0.45—185.2 mIU•m^-1. And in thedetections of clinical serum samples, the related coefficient between the two methods’results was 0.955. Full article

A sensitive and rapid method was developed for the determination of cAMP inLocusta migratoria manilensis Meyen by high-performance liquid chromatography withfluorescence detection. The cAMP was derivatized using chloroacetaldehyde and TBASbuffer/methanol was used as the mobile phase. A detection quantification of 40 fmol/mlcould be achieved when using fluorescence detection. An HPLC-MS method using DMHAas an ion-pair agent to analyze cAMP was also demonstrated. We studied the effect ofdopamine and other stimulants on cAMP levels from isolated locust central nervoussystems. The new method is well suited for the analysis of cAMP in small biologicalsamples. Full article

The crystal structure of RU60358, C₂₀H₂₁NO₃, has been determined using X-raydiffraction to establish the configuration and stereochemistry of the molecule around theC15-C16 triple bond. The compound crystallises in the orthorhombic space group P2₁2₁2₁, a= 7.7575, b = 11.3182, c = 21.3529å, V = 1874.80å3 and Z = 4. The structure has beenrefined to a final R = 0.068 for the observed structure factors with I ≥ 3σ (I). The refinedstructure was found to be significantly non planar. A comparative study, using the ab initiocalculations of the structure at B3LYP/6-31G** levels of theory, shows good geometricalagreement with the X-ray diffraction data. Standard deviations between the calculated andexperimental bond values have been shown to be 0.01 å and 0.5° for bond angles.Vibrational wavenumbers were obtained from a normal mode analysis using the ab initiocalculations. Full article