stability of the ;-; stacking interactions in the substituted-coronene||cyclooctatetraene complexes wasstudied using the computational quantum chemistry methods (where || denotes ;–; stackinginteraction, and substituted-coronene is coronene which substituted with four similar x groups; x =oh, sh, h, f, cn, and no). there are meaningful correlations between changes of geometricalparameters and t...

the physical and chemical properties of pyrazole and pyrazoline molecules were theoreticallystudied by gaussian 03, software with nmr and molecular orbital calculations at b3lyp/6-31g andb3lyp/6-31+g(d) levels, in gas phase and solution. in this study a comparison effect of threesolvents with different dielectric constants on pyrazole and pyrazoline molecules in aspect energyinteraction between...

in this work, the effects of as-doped on the adsorption of oxygen gas on the outer and inner surface ofboron nitride nanotube (bnnts) is investigated. the structural parameters, quantum properties involving:bond length, bond angle, homo-lumo orbital, gapenergy, electron affinity, electronegativity, chemicalpotential, global hardness, global softness and nmr parameters of bnnts are calculated at...

the fullerene structures of c20cage and bowl,c20h10 and their n-doped structures as c20cage nh,c20bowl nh, c20h10nh, c20h10n and their isomers are optimized using the mpw1pw91/6-31g level of the theory. magnetic shielding tensors of 14n and 13c atoms are calculated by the same level of the theory. results show that doping an n atom on fullerenes affects differently on the chemical shielding of ...

the alginate was extracted with six different methods from iran south seacoast algae, sargassum sp, and the percentage yield of alginate was determined. we divided our methods to two groups including acidic extraction and non-acidic. in acidic methods, hcl and h 2 so 4 were used as a detergent in extraction process and cacl 2 was exerted in non-acidic treatments. all treatments compared with ea...

in this study the chemical properties of b6c4si and c16 clusters connected vitamin c have been investigated using density functional theory (dft). nmr parameters and homo- lumo gap energy are calculated by using density functional method (b3lyp) with 6-311g* basis set. calculations show that homo- lumo gap energy of vitamin c decreases after connecting to b6c4si or c16 cluster decreasing of hom...

the 1h and natural-abundance 13c-nmr spectra of 1-thiacyclooctan-3-one (1) have been measured from 25 to -100°c. coalescence is observed in the 1h-nmr spectra of (1) at about -80°c, and attributed to ring inversion in a boat-chair conformation, which is the predominant conformation of (1). the free energy of activation (dg¹) for this process is 9.2±0.2 kcal/mol. the 13c-nmr spectra of (1) is te...