68682-49-5Relevant academic research and scientific papers
DICARBOXYLIC ACID MONOMERS AND METHODS OF MAKING AND USING THE SAME
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Paragraph 0297, (2015/12/07)
Disclosed herein are phenylindane dicarboxylic acid (PIDA) monomers, polymer compositions comprising the PIDA monomers, and methods of preparing PIDA monomers. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.
Radical ions in photochemistry. Carbon-carbon bond cleavage of radical cations in solution: Theory and application
Popielarz,Arnold
, p. 3068 - 3082 (2007/10/02)
The cleavage of radical cations of two series of alkanes, 1,1,2-triaryl- and 1,1,2,2-tetraarylalkanes, generated by photoinduced single electron transfer in acetonitrile-methanol, occurs with formation of radical and carbocation fragments. The radical cations of some unsymmetrically substituted alkanes cleave to give all four of the possible products, two hydrocarbons emanating from the radicals and two methyl ethers from the carbocations, in proportion to the oxidation potentials of the two possible radical fragments. There is an excellent linear correlation between the logarithm of the observed ratio of products and that calculated from the reported electrochemically determined oxidation potentials (r = 0.998, 5 points). The proportionality constant (1.27) for this relationship is close to unity which indicates that the product ratio is determined by the relative rates of cleavage in the two possible modes or by equilibration of the radicals and carbocations before separation of the geminate radical carbocation pair and not by equilibration upon reencounter of freely solvated radical and carbocation fragments. The effect of temperature on the relative oxidation potentials of the radicals studied is small and can be neglected when radicals of the same order (i.e., both secondary or both tertiary) and of similar size are compared. The ratio of products obtained upon cleavage of the radical cation at 25 °C can be used to determined standard oxidation potentials of radicals. The oxidation potential of the diphenylmethyl radical (0.350 V vs SCE) has been accepted as the primary standard and the (4-methyl-phenyl)phenylmethyl (0.265 V) and bis(4-methylphenyl)methyl (0.188 V) radicals are established as secondary standards against which the oxidation potentials of other radicals can be measured. Oxidation potentials of several 4-substituted cumyl radicals have been determined by this photochemical method. There is a good (r = 0.987, 5 points) linear correlation between the measured oxidation potentials and the σ+ substituent constants. The reaction constant is appropriately negative and large (p = -6).
Substituent effects on benzyl radical hyperfine coupling (hfc) constants. Part 3. Comparison of the α-hfc for substituted benzyl radicals with the β-hfc for substituted cumyl radicals
Arnold, Donald R.,Nicholas, A. Martin de P.,Snow, Miles S.
, p. 1150 - 1156 (2007/10/02)
The electron spin resonance (esr) spectra of eighteen para-substituted cumyl radicals were analyzed.The relationship between the β-hyperfine coupling (β-hfc) constants of these cumyl radicals and the corresponding α-hfc constants of benzyl radicals was studied.Although there is a general trend for the α- and β-hfc values to vary in a similar manner, specific deviations from a linear correlation between these parameters were observed.These deviations were rationalized by considering charge effects on spin delocalization.The correlation coefficient for the linear regression analysis of these α- and β-hfc values was found to significantly improve when parameters reflecting charge effects on spin delocalization were included in an extended Hammett treatment of the spectral data.
