Structure and photochemistry of matrix-isolated o-phthalaldehyde

Abstract

Two conformers, (EZ) and (EE), were observed in o-phthalaldehyde (1) isolated in nitrogen and argon matrices. The E-enol (5E) generated upon photolysis (λ 313 nm) of the matrix-isolated (1) was stabilized and characterized by UV and IR absorption spectroscopy. Further irradiation of (5E) resulted in intramolecular cyclization (λ > 357 nm) to phthalide (2) or fragmentation (λ= 313 nm) to carbon monoxide and benzaldehyde (7).