92346-29-7Relevant academic research and scientific papers
Type II Photochemistry of Ketones in Liquid Crystalline Solvents. The Influence of Ordered Media on Biradical Dynamics
Hrovat, David A.,Liu, Jerry H.,Turro, Nicholas J.,Weiss, Richard G.
, p. 7033 - 7037 (2007/10/02)
The Norrish type II photochemistry of five alkylphenones, PhCO(CH2)nH (1a, n=4; 1b, n=10; 1c, n=17; 1d, n=19; 1e, n=21), 10-nonadecanone (2), and 2-undecanone (3) was studied in the isotopic, smetic, and solid phases of n-butyl stearate.The ratio of elimination-to-cyclization products for ketones 1c-e and 2 exhibits a strong phase dependence with a 7-8-fold increase in the smectic phase relative to the isotropic phase.The ratio of isomeric cyclobutanols from 2 shows a similar change.Further increases in the elimination-to-cyclization ratio are observed for 1d in the solid phase.The product ratios for ketones 1a, 1b, and 3 are the same in all the phase studied.Transient absorption studies on the intermediate 1,4-biradical produced from laser flash photolysis of 1d yield lifetimes of 64 +/- 5 and 70 +/- 5 ns in the isotopic and smectic phases, respectively.These results are explaned in terms of the structures of the various phases of n-butyl stearate and the accepted behavior of Norrish type II biradicals.
