Reactive intermediates formed by the consecutive photolyses of naphthalenetetracarboxylic dianhydrides: direct observation of reactive intermediates generated by laser-induced reaction in low-temperature argon matrices

Photolyses of 1,2;5,6- and 2,3;6,7-naphthalenetetracarboxylic dianhydrides (1 and 2), which would be precursors of 1,5- and 2,6-naphthdiynes, respecti vely, were studied by matrix isolation and wavelength-selective irradiation techniques in order to directly observe intermediates produced stepwise. T he photolyzed products in the matrices were characterized by FT-IR and UV-V is spectroscopies with the aid of density functional theory calculations. A s a result of decarboxylation and decarbonylation of dianhydride precursors , the generation of naphthyne intermediates was confirmed in both the cases of I and 2. The photolyses of these naphthyne intermediates resulted in th e formation of acetylenic compounds as in the case of benzdiynes. In the ph otolysis of 1, the final compound was assigned to deca-5-ene-1,3,7,9-tetray ne, although it was unidentified in the case of 2. (C) 2001 Elsevier Scienc e B.V. All rights reserved.