title: Substituent electronic effects on the persistence and absorption spectra of (Z)-o-xylylenols. A nanosecond laser flash photolysis study.
abstract: [reaction: see text] A systematic investigation on a broad set of aldehydes reveals that the lifetimes of (Z)-photoenols can be modulated by variation of the substituents. We have found that the lifetimes of (Z)-enols (in benzene) can be varied by more than 1 order of magnitude with a judicious choice of the substituents that exert mesomeric and inductive effects as, for example, in the case of pentamethylbenzaldehyde (tau = 35 ns) and dicyanomesitaldehyde (tau = 760 ns). This study thus points to the fact that the electronic factors in conjunction with hydrogen bonding stabilization can considerably broaden the uni- as well as bimolecular chemistry based on photoenolization. Further, we have shown that the photoenols exhibit dramatic shifts in their absorption properties with variation of the substituents; although the photoenols have long been considered to be colored, their absorption properties have not been heretofore comprehensively examined.
authors.affiliation: Department of Chemistry, Indian Institute of Technology, Kanpur 208 016, India.
authors.forename: Apurba L
authors.initials: AL
authors.lastname: Koner
authors.forename: Nidhi
authors.initials: N
authors.lastname: Singhal
authors.forename: Werner M
authors.initials: WM
authors.lastname: Nau
authors.forename: Jarugu Narasimha
authors.initials: JN
authors.lastname: Moorthy