The photophysical and photochemical behaviors of a series of secondary and tertiary ω-(β-styryl) aminoalkanes with one to five methylene groups separating the styryl and amino groups have been investigated and compared with the intermolecular reactions of trans-and cis-1-phenylpropene with secondary and tertiary amines. The tertiary styrylamines form fluorescent intramolecular exciplexes but fail to undergo intramolecular addition reactions. Both the rate constant for exciplex formation and the stability of the exciplex are dependent upon the length of the polymethylene chain connecting the chromophores. The secondary styrylamines do not form fluorescent exciplexes; however, the dependence of the styrene singlet lifetime upon the polymethylene chain length is similar to that for the tertiary styrylamines. Intramolecular NH addition to the styrene double bond results in the formation of two regioisomeric (α-phenyl and α-benzyl) cyclic amines of different ring sizes. The regioisomer of larger ring size is favored except in the case in which four methylene groups separate the chromophores. The effects of the polymethylene chain length, the solvent polarity, the temperature and the bulk of the N-alkyl group upon product yields and ratios are discussed in terms of a mechanism involving singlet exciplex and biradical intermediates.
|Original language||English (US)|
|Number of pages||16|
|Journal||Journal of Photochemistry and Photobiology, A: Chemistry|
|State||Published - Apr 30 1992|
ASJC Scopus subject areas
- Chemical Engineering(all)
- Physics and Astronomy(all)