and density functional theory calculations reveal unique photophysical properties of the D-A-type imines. Furthermore, the reactivity of the D-A-type imines is demonstrated by using them as a photoredox catalyst for atom-transfer radical addition. These findings illuminate a previously neglected chemical space in the field of photochemistry, which will be exploited by taking advantage of the inherent
Intermolecular Atom Transfer Radical Addition to Olefins Mediated by Oxidative Quenching of Photoredox Catalysts
作者:John D. Nguyen、Joseph W. Tucker、Marlena D. Konieczynska、Corey R. J. Stephenson
DOI:10.1021/ja108560e
日期:2011.3.30
Atom transfer radical addition of haloalkanes and α-halocarbonyls to olefins is efficiently performed with the photocatalyst Ir[(dF(CF(3))ppy)(2)(dtbbpy)]PF(6). This protocol is characterized by excellent yields, mild conditions, low catalyst loading, and broad scope. In addition, the atom transfer protocol can be used to quickly and efficiently introduce vinyl trifluoromethyl groups to olefins and
No photocatalyst required – versatile, visible light mediated transformations with polyhalomethanes
作者:Johannes F. Franz、Wolfgang B. Kraus、Kirsten Zeitler
DOI:10.1039/c4cc10270c
日期:——
Visible light activation of polyhalomethanes offers a versatile, photocatalyst-free method for the α-CH functionalization of amines and for regioselective Kharasch-type additions.
Photoredox catalysis <i>via</i> consecutive <sup>2</sup>LMCT- and <sup>3</sup>MLCT-excitation of an Fe(<scp>iii</scp>/<scp>ii</scp>)–N-heterocyclic carbene complex
作者:Aleksandra Ilic、Jesper Schwarz、Catherine Johnson、Lisa H. M. de Groot、Simon Kaufhold、Reiner Lomoth、Kenneth Wärnmark
DOI:10.1039/d2sc02122f
日期:——
sizable charge transfer excited state lifetimes ≥0.1 ns in both oxidation states, and the Fe(III) 2LMCT and Fe(II) 3MLCT states are strong oxidants and reductants, respectively. The combined reactivity of both excitedstates enables efficient one-electron reduction of the alkyl halide substrate under green light irradiation. The two-photon mechanism proceeds via reductive quenching of the Fe(III) 2LMCT
Fe-N-杂环卡宾(NHC)配合物作为光敏剂和光氧化还原催化剂越来越受到关注。这些应用通常依赖于足够长的激发态寿命和有效的双分子猝灭,这导致迄今为止成功使用 Fe-NHC 配合物的例子很少。在这里,我们采用了[Fe( III )(btz) 3 ] 3+ (btz = (3,3'-dimethyl-1,1'-bis( p -tolyl)-4,4'-bis(1,2 ,3-triazol-5-ylidene)))通过可见光介导的原子转移自由基加成 (ATRA) 将卤代烷添加到烯烃和炔烃中。与其他 Fe-NHC 配合物不同,[Fe( III / II )(btz) 3 ] 3+/2+受益于相当大的电荷转移激发态寿命,两种氧化态均≥0.1 ns,Fe( III ) 2 LMCT 和 Fe( II ) 3 MLCT 态分别是强氧化剂和还原剂。两种激发态的组合反应性使得卤代烷底物在绿光照射下有效的单电子
Visible Light-Mediated Atom Transfer Radical Addition via Oxidative and Reductive Quenching of Photocatalysts
作者:Carl-Johan Wallentin、John D. Nguyen、Peter Finkbeiner、Corey R. J. Stephenson
DOI:10.1021/ja300798k
日期:2012.5.30
visible light-mediated atom transfer radical addition (ATRA) of haloalkanes onto alkenes and alkynes using the reductive and oxidativequenching of [IrdF(CF(3))ppy}(2)(dtbbpy)]PF(6) and [Ru(bpy)(3)]Cl(2) is presented. Initial investigations indicated that the oxidativequenching of photocatalysts could effectively be utilized for ATRA, and since that report, the protocol has been expanded by broadening