microstructural investigation of low molecular weight 1,4-polybutadiene (1,4-pbd) was studied by 1h and 13c nuclear magnetic resonance spectroscopy (nmr). the isomer contents of 1,4-cis, 1,4-trans and 1,2- vinyl in polybutadiene microstructure were determined. the number average molecular weight for low molecular weight polybutadiene was measured by nmr techniques and comparison was made with g...

A detailed investigation of the reaction path for the thermal w x rearrangement of 3,4-dihydro-1a H-azirine 2,3-c pyrrol-2-one to yield a cyanoketene]formaldimine complex is carried out at the MP2r6-31G* and B3LYPr6-31G* levels of theory. The ring opening of the five-membered pyrrolinone ring and the formation of the nitrile group takes place in a concerted manner, presenting a significant stra...

To investigate the effects of electron-donating and electron-withdrawing substituents upon the reaction of porphyrins with osmium tetraoxide, and the pinacol-pinacolone rearrangement of the resulting diols, a series of meso-substituted porphyrins were prepared by total synthesis. Porphyrins with electron-donating substitutents at the meso-positions gave vic-dihydroxychlorins in which the adjace...

This work reports on the investigation of the photosensitive polymer poly(diphenyl bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylate) (PPNB), which undergoes the photo-Fries rearrangement upon illumination with UV-light, used as interfacial layers in organic electronic devices. Two cases were investigated: the use of a blend of PPNB with poly-vinylcarbazole (PVK) as an interlayer in para-sexiphenyl (P...

The vinylidene radical ( H2C=Cr) is the simplest unsaturated carbenc and is postulated to be a reactive intermediate in a number of reactions [ 1 ,?I, such as in the combination of two CH2 radicals to produce acetylene_ It is particularly interesting in that it rearranges by a 1.7 hydrogen shift. an important process in the chemistry of txrbenes [3]_ Extensive calculations have been done on the...

Intramolecular nucleophilic aromatic substitution (Truce–Smiles rearrangement) of the anions 2-benzyl benzanilides leads to triarylmethanes in an operationally simple manner. The reaction succeeds even without electronic activation ring that plays role electrophile SNAr reaction, being accelerated instead by preferred conformation imposed tertiary amide tether. substituent product may be remove...

Resonant inelastic x-ray scattering spectra excited at the ${\ensuremath{\pi}}^{*}$-resonance of nitrogen molecule are presented. Well-resolved vibrational excitations in electronic ground state, and $3{\ensuremath{\sigma}}_{g}^{\ensuremath{-}1}1{\ensuremath{\pi}}_{g}^{1}\phantom{\rule{4pt}{0ex}}{a}^{1}{\mathrm{\ensuremath{\Pi}}}_{g}$ state observed. The analyzed within Kramers-Heisenberg forma...

a facility layout problem is concerned with determining the best position of departments, cells, or machines on the plant. an efficient layout contributes to the overall efficiency of operations. it’s been proved that, when system characteristics change, it can cause a significant increase in material handling cost. consequently, the efficiency of the current layout decreases or is lost and it ...