Wydział Chemii

Joanna Grzegorzek

Zofia Mielke

2010

European Journal of Organic Chemistry

5301-5309

0.1002/ejoc.201000348

Naukowa

Angielski

Artykuł

The photochemistry of salicylaldoxime in solid argon hasbeen investigated by FTIR spectroscopy and DFT calcula-tions. The salicylaldoxime molecule trapped in the matrixfrom the vapor above the solid sample has the most stablesyn1conformation with an intramolecular hydrogen bond. Ir-radiation (λ
320 nm) leads to conversion of thesyn1con-former into thesyn3one, in which the C(H)NOH and (C)OHgroups are rotated around the C–C and C–O bonds, respec-tively, and the intramolecular hydrogen bond is broken. Thephotochemistry ofsyn3involves three possible routes:(i) conversion ofsyn3intoanti2conformer, this process re-quires rearrangement of the NOH group with respect to the C=N bond; (ii) photodissociation of salicylaldoxime into 2-cy-anophenol and water, which form a hydrogen-bonded com-plex; and (iii) regeneration of thesyn1conformer. The thirdroute is a very small contribution to the overall process. Thestudy performed with [D2]salicylaldoxime indicates that thedehydration reaction of salicylaldoxime involves cleavage ofthe N–O bond and formation of OH and Ph(OH)C(H)N radi-cals in the first step. Then, the OH radical abstracts a hydro-gen atom from the CH group to form 2-cyanophenol andwater molecules. When the sample is exposed to the full out-put of the mercury lamp the 2-cyanophenol complex withwater becomes the dominating product.

oximes, photochemistry, isomerization, Matrix isolation, Density functional calculations

http://dx.doi.org/0.1002/ejoc.201000348

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