Thermally activated phenyl group

The model which has been developed (2>1) to fit these results involves formation of excimers via thermally activated phenyl group motion. Such motion is restricted in a rigid matrix, and "pre-form-ed" excimer sites, where little phenyl motion would be required for collapse to the excimer, are evidently rare. 

This carbyne was shown not to be the RCM active species. At —20 °C it rearranged spontaneously into the indenylidene complex XV with release of TfOH. This intramolecular transformation corresponds to the electrophilic ortho-substitution of one phenyl group by the electrophilic carbyne carbon of XIV. The carbene complex XV was identified as the species thermally formed in situ from the catalyst precursors Ia,b in the range 25-80 °C. 

Intramolecular [2 + 2] cycloaddition of acyclic substrates take place when some activating substituent is present for hydrocarbons, conjugating vinyl or phenyl groups are sufficient. Tetraene (53) gives products (54) and (55), and the diphenylheptadiene (56) is converted thermally to the bicyclo[3.2.0] system (57). ... 

Dithienothiophenes give cation polymeric radicals capable of further copolymer addition" while polystryene with a narrow polydispersity has been prepared through the use of an end-capped photoactive anthryl group. ° Large differences in radical termination rates have been found to be responsible for the marked variations in molecular weights of polymer from the UV flash polymerisation of 1,3-butadiene. tra 5-l,2-bis(5-Phenyl-2-oxazolyl)ethene has been found to exhibit low laser conversion efficiency due to preferential dimerisation while thermally activated patterns can be formed on the surface of poly(methyl methacrylate) by coating with photodimerisable 9-anthraldehyde. " ... 

No thermal ring openings are observed for conventional cyclopropyl anions, even if they carry two phenyl groups to provide stabilization of the potential terminus of the allyl anion. CH acidic optically active precursors of cyclopropyl anions exhibit a very high degree of retention of configuration when treated with bases in polar protic solvents and in most cases in aprotic solvents, too. - ... 

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