103367-53-9Relevant academic research and scientific papers
Quantitative cavities and reactivity in stages of crystal lattices: Mechanistic and exploratory organic photochemistry
Zimmerman, Howard E.,Nesterov, Evgueni E.
, p. 2818 - 2830 (2007/10/03)
In continuing our research on solid-state organic photochemistry, we have been investigating the phenomenon of reactivity in stages. In this study we present new examples where the photochemical reactivity changes discontinuously at some point in the conversion. In these instances, the reaction course of the solid differs from that in solution. One example is the reaction of 2-methyl-4,4-diphenylcyclohexenone, where an unusual reaction course was encountered in the solid state; and, of two possible mechanisms, one was established by isotopic labeling. A second case is that of 4,5,5-triphenylcyclohexenone. The solid-state reaction of this enone was found to give a new photochemical transformation, the Type C rearrangement, a process that involves a δ to α aryl migration. In the case of 3-tert-butyl-5,5-diphenylcyclohexenone the Type C rearrangement occurred even in solution. The stage behavior was investigated using X-ray analysis and Quantum Mechanics/Molecular Mechanics computations. This permitted us to determine the sources and details of the stage phenomenon. The analysis revealed how a product molecule as a neighbor affects reactivity. The computations were employed to follow the course of a solid-state reaction from reactant through the succeeding stages. Additionally, the Delta-Density Analysis was utilized to ascertain the electronic nature of molecular changes. Besides product composition changing with extent of conversion, the reaction quantum yield was found to change as one stage gave way to a succeeding one.
Photochemistry of Organic Molecules Entwined in Spiderwebs; The Use of Poly(methyl methacrylate) Glass for Restricting Excited-State Motion
Zimmerman, Howard E.,O'Brien, Michael E.
, p. 1809 - 1816 (2007/10/02)
A study of several unimolecular photochemical rearrangements in poly(methyl methacrylate) glass was carried out with the intent of comparing the behavior of excited-state species trapped in a polymer matrix with both the corresponding solution photochemistry and that in crystal lattices.Three reactants were studied: (a) 4,5,5-triphenylcyclohex-2-en-1-one, (b) 1,1-dicyano-3,3,5,5-tetraphenyl-1,4-pentadiene, and (c) 2,2-dimethyl-1,1-diphenyl-3-(2,2-diphenylvinyl)cyclopropane.The solution photochemistry of the three compounds had previously been studied in our laboratory, and the photochemistry in the crystal lattice had been similarly investigated for the first two.The crystal lattice photochemistry of the last of the three was investigated in the present study.For each of the three reactants, different photochemical behavior was observed depending on the environment-polymer glass, solution, or crystal lattice.The experimental behavior correlated nicely with theoretical assessment of molecular motion of the component atoms in proceeding onward from that point along the reaction coordinate where multiple reaction pathways are available.The preferred reaction pathway proved consistently to require the least motion and the minimum molecular volume displacement.A concept of least motion dependent on its application to the "branch point" rather than the entire conversion of reactant to product was established.
Photochemistry in a Box. Photochemical Reactions of Molecules Entrapped in Crystal Lattices: Mechanistic and Exploratory Organic Photochemistry
Zimmerman, Howard E.,Zuraw, Michael J.
, p. 7974 - 7989 (2007/10/02)
An exploration was made of the photochemical behavior in the crystalline state of a series of molecules we have previously studied in solution.The reactions studied fall into the categories of cyclohexenone rearrangements, reactions of di-?-methane system
