A Robust Palladium(II)–Porphyrin Complex as Catalyst for Visible Light Induced Oxidative CH Functionalization. Issue 18 (5th March 2013)

• Record Type: Journal Article
• Authors: To, Wai‐Pong; Liu, Yungen; Lau, Tai‐Chu; Che, Chi‐Ming
• Is Part Of: Chemistry. Volume 19:Issue 18(2013)
• Page Start: 5654
• Page End: 5664
• Publication Date: 2013-03-05
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201203774
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>A series of palladium(II)–porphyrin complexes that display dual emissions with lifetimes up to 437 μs have been synthesized. Among the four complexes, <bold>PdF₂₀TPP</bold> is an efficient and robust catalyst for photoinduced oxidative CH functionalization by using oxygen as terminal oxidant. α‐Functionalized tertiary amines were obtained in good to excellent yields by light irradiation (<italic>λ</italic>&gt;400 nm) of a mixture of <bold>PdF₂₀TPP</bold>, tertiary amine, and nucleophile (cyanide, nitromethane, dimethyl malonate, diethyl phosphite, and acetone) under aerobic conditions. Four examples of intramolecular cyclized amine compounds could be similarly prepared. Comparison of the UV‐visible absorption spectra before and after the photochemical reaction revealed that <bold>PdF₂₀TPP</bold> was highly robust (&gt;95 % recovery). The practical application of <bold>PdF₂₀TPP</bold> has been revealed by the photochemical reactions performed by using a low catalyst loading (0.01 mol %) and on a 10 mmol scale. The <bold>PdF₂₀TPP</bold> catalyst could sensitize photoinduced oxidation of sulfides to sulfoxides in excellent yields. Mechanistic studies revealed that the photocatalysis proceeded by singlet‐oxygen oxidation.</p> </abstract>