Laser flash photolysis of nanocrystalline α-azido-p-methoxy-acetophenone. Issue 35 (29th August 2017)

• Record Type: Journal Article
• Authors: Sarkar, Sujan K.; Gatlin, DeVonna M.; Das, Anushree; Loftin, Breyinn; Krause, Jeanette A.; Abe, Manabu; Gudmundsdottir, Anna D.
• Is Part Of: Organic & biomolecular chemistry. Volume 15:Issue 35(2017)
• Page Start: 7380
• Page End: 7386
• Publication Date: 2017-08-29
• Subjects: Chemistry, Organic -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1039/c7ob01731f
• Languages: English
• ISSNs: 1477-0520

Abstract

Abstract : Irradiation of nanocrystals of azide1 results in a solid-to-solid photoreaction that forms imine2 in high chemical yield. Abstract : Irradiation of nanocrystals of azide1 results in a solid-to-solid reaction that forms imine2 in high chemical yield. In contrast, solution photolysis of azide1 yields a mixture of products, with7 as the major one. Laser flash photolysis (LFP) of a nanocrystalline suspension of azide1 in water shows selective formation of benzoyl radical4 ( λ max ∼ 400 nm), which is short-lived ( τ = 833 ns) as it intersystem crosses to form imine2 . In comparison, LFP of azide1 in methanol reveals the formation of triplet alkylnitrene10 ( λ max ∼ 340 nm). The selectivity observed in the solid-state is related to stabilization of the triplet ketone with (n, π*) configuration by the crystal lattice, which results in α-cleavage being favored over triplet energy transfer to the azido chromophore. Both the solid-state and solution reaction mechanisms are further supported by density functional theory calculations. Thus, laser flash photolysis has been used to effectively elucidate the medium dependent reaction mechanisms of azide1 .