Time-resolved EPR investigation of potential model systems for acrylate polymer main chain radicals based on esters of Kemp's tri-acid.
J Phys Chem B
; 113(19): 6623-9, 2009 May 14.
Article
in En
| MEDLINE
| ID: mdl-19374361
ABSTRACT
Methyl esters of Kemp's tri-acid and cyclohexanetricarboxylic acid are structurally similar to acrylate polymers, having the same functionalities and stereoregularities as poly(methylmethacrylate) and poly(methylacrylate), respectively. The photochemistry and free radicals from these model systems have been studied using time-resolved electron paramagnetic resonance spectroscopy with laser flash photolysis at 248 nm. Chemically induced electron spin polarization from the triplet mechanism (net emission) is observed. Well-resolved spectra are obtained at all temperatures for the model system radicals, which are determined to be in the slow motion condition, that is, there is no interconversion of chair conformations. The temperature dependence of the spectra is minimal; some hyperfine lines shift as the temperature increases, but without much broadening. Density functional theory calculations are presented and discussed in support of the experimental data.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
J Phys Chem B
Journal subject:
QUIMICA
Year:
2009
Type:
Article
Affiliation country:
United States