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• 4356-69-8 1,1-bis-(4-methoxyphenyl)ethylene 
• 10543-21-2 1,1-bis(4-methoxyphenyl)ethane 

Relevant academic research and scientific papers

Site-selective bimodal absorption and emission of distonic radical cation

Figure presented An acyclic 1,4-distonic dimer radical cation (DAE 2+) was generated from the dimerization of 1,1-bis(4-methoxyphenyl)ethylene radical cation (DAE+) with the neutral molecule (DAE) in solution. The absorption spectrum of DAE 2+ shows bimodal absorption bands with peaks at 350 and 500 nm corresponding to the 1,1-bis(4-methoxyphenyl)ethyl radical (An 2CCH3) and 1,1-bis(4-methoxyphenyl)ethyl cation (An2C+CH3), respectively. Therefore, DAE2+ in the ground state has the spin and positive charge localized on the 1- and 4-positions, respectively. The bimodal characteristic emissions by the site-selective excitation of radical and cation sites of DAE2+ were observed at 77 K, showing that the excitation energy is localized on the radical or cation site of DAE 2+ in the excited state. The interaction between radical and cation sites of DAE2+ in the ground and excited states are discussed on the basis of the steady-state spectroscopic and transient absorption measurements, as well as theoretical calculations.

Lifetimes and UV-visible absorption spectra of benzyl, phenethyl, and cumyl carbocations and corresponding vinyl cations. A laser flash photolysis study

Benzyl (4-MeO, 4-Me, and 4-methoxy-1-naphthylmethyl), phenethyl (4- Me2N, 4-MeO, 3,4-(MeO)2, 4-Me, 3-Me, 4-F, 3-MeO, 2,6-Me2, parent, and 4- methoxy-1-naphthylethyl) and cumyl (4-Me2N, 4-MeO, 4-Me, parent) cations have been studied by laser flash photolysis (LFP) in 2,2,2-trifluoroethanol (TFE) and 1,1,1,3,3,3-hexafluoroisopropanol (HFIP). In most cases styrene or α-methylstyrene precursors were employed for the phenethyl and cumyl ions, the intermediate being obtained by solvent protonation of the excited state. Benzyl cations were generated by photoheterolysis of trimethylammonium and chloride precursors. While a 4-MeO substituent provides sufficient stabilization to permit observation of cations in TFE, cations with less stabilizing substituents usually require the less nucleophilic HFIP. Even in this solvent, the parent benzyl cation is too short-lived (lifetime 6H4C+(R)-CH3 (R = Me, Et, i-Pr, t-Bu, cyclopropyl, C6H5, 4-MeOC6H4) were generated in TFE via the photoprotonation route. The alkyl series shows that steric effects are important in the decay reaction. The cation with R = cyclopropyl is a factor of 1.5 less reactive than the cation where R = phenyl. Several vinyl cations have also been generated by photoprotonation of phenylacetylenes. ArC+=CH2 has a reactivity very similar to that of its analog ArC+H-CH3, the vinyl cation being slightly (factors of 2-5) shorter-lived. For the various series of cations, including vinyl, substituents in the aryl ring have a consistent effect on the κ(max), a shift to higher wavelength relative to hydrogen of 15 nm for 4-Me, 30 nm for 4-MeO, and 50 nm for 4-Me2N.

STRUCTURAL EFFECTS IN SOLVOLYTIC REACTIONS. 45. CARBON-13 NMR STUDIES OF CARBOCATIONS. 9. VARIATION OF CATIONIC CARBON CHEMICAL SHIFTS WITH INCREASING ELECTRON DEMAND IN 1,1-DIARYL-1-ETHYL CARBOCATIONS. IMPORTANCE OF THE INDUCTIVE LOCALIZED pi -POLARIZATI

Carbocations were prepared in either SbF//5/FSO//3H/SO//2ClF or FSO//3H/SO//2ClF solutions at minus 78 degree C and their **1**3C NMR spectra recorded at minus 70 degree C. The plots of the substituent chemical shifts DELTA delta C** plus against sigma **