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...

The electrochemical oxidation of methyl catechol in the presence of 2-thiouracil (as a nucleophile) has beenperformed in aqueous solutions using cyclic voltammetry and controlled-potential coulometric techniques.The electrochemical behavior of methyl catechol in the presence of 2-thiouracil was investigated. Theelectrochemical synthesis of this compound has been successfully performed in an und...

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...

a new homologous series of linear aliphatic polyesters, such as poly (cis-2- butenylene carboxylate)s, pbms (m is the number of methylene groups in the acid component, m=2-8 have been synthesized by direct polyesterification reactions in anisole, as solvent. ft-ir, 400 mhz h- nmr, c-nmr and elemental analysis were used to establish the structure of polyesters. molecular weight distributions wer...

nano silica sulfuric acid as a solid acid, was described to be an effective catalyst for one-pot three-component reaction of kojic acid, aryl aldehydes and indoles for the preparation of 2-substituted aryl (indolyl) kojic acid derivatives. the catalyst was prepared by combination of chlorosulfonic acid to nano silica gel. the size of nanoparticles were observed with sem.all prepared compounds w...