the effects of substituents on the symmetry and the nature of halogen bonds in [n∙∙∙x∙∙∙n]+-type systems are presented for the yc5h4n∙∙∙x∙∙∙nc5h5 (y = no2, cn, h, ch3, och3, oh, nh2, x = cl, br, i) complexes. some structural parameters, energy data and electronic properties were explored with the density functional theory (dft) calculations. in addition, electrostatic potentials were used in es...

background : hyperbaric and isobaric bupivacaine has been shown to reduce bispectral index (bis) during spinal anesthesia. the aim of this study was to compare the effect of isobaric bupivacaine and hyperbaric bupivacaine on the bis during cesarean section with spinal anesthesia. methods : in this double-blind randomized controlled clinical trial, 84 pregnant women with asa ( american society o...

The reaction of 3,3-dichloro-2,2,4,4-tetramethylcyclobutanethione (1) with diazo compounds yielded spirocyclic 2,5-dihydro-1,3,4-thiadiazoles 3, which decomposed at ca. 45°C to give the corresponding thiocarbonyl ylide of type 4. In the absence of trapping agents, these thiocarbonyl ylides underwent a 1,3-dipolar electrocyclization to yield spirocyclic thiiranes 5. On the other hand, the thioca...

Chem. Abstr. Services Reg. No.: 1675-54-3 Chem. Abstr. Name: 2,2' -r (I-Methylethylidene )bis( 4, I-phenyleneoxyethylene) )bis(oxiane) . IUPAC Systematic Name: 2,2'-r(1-Methylethylidene)bis(4,i-phenyleneoxyethylene) )bis( oxiane ) Synonym: 4,4' -Bis(2,3-epoxyropoxy)diphenyldimethylmethane; 2,2-bisfpara-(2,3epoxyropoxy)phenyl)propane; 2,2-bisr 4-(2,3-epoxyropoxy)phenyl)propane; bis( 4glycidyloxy...

polyvinyl butyral (pvb) was synthesized by condensation reaction of polyvinyl alcohol (pva) with butanal in aqueous medium containing an effective emulsifier and an inorganic acid as catalyst. the product was characterized by, ir, tg and dtg techniques. percentage of vinyl alcohol groups in the pvb was determined by a chemical method according to a standard method. some clear and soft film samp...