Main observation and conclusion Stereoselective isomerization of a-alkyl styrenes is accomplished using a new iron catalyst supported by phosphine-pyridine-oxazoline(PPO)ligand.The protocol provides an atom-efficient ...Main observation and conclusion Stereoselective isomerization of a-alkyl styrenes is accomplished using a new iron catalyst supported by phosphine-pyridine-oxazoline(PPO)ligand.The protocol provides an atom-efficient and operationally simple approach to trisubstituted alkenes in high yields with excellent regio-and stereoselectivities under mild conditions.The results of deuterium-labelling and radical trap experiments are consistent with an iron-hydride pathway involving reversible alkene insertion andβ-H elimination.展开更多
Controlling properties of crystalline solids by light remains a challenge because the lack of intrinsic structural flexibility limits the necessary molecular mobility for photoisomerization. In this work, we reported ...Controlling properties of crystalline solids by light remains a challenge because the lack of intrinsic structural flexibility limits the necessary molecular mobility for photoisomerization. In this work, we reported a series of visible-light-responsive covalent organic frameworks (COFs) by introducing donor-acceptor Stenhouse adducts (DASAs) with various electron-withdrawing moieties via a post-modified strategy. The DASAs-functionalized COFs exhibit distorted honeycomb layered topology with long-range periodicity. The DASAs grafted on the skeletons are pointing into the nanopores of COFs, which weakens intermolecular aggregation and ensures sufficient free volume to undergo reversible isomerization between linear and cyclic states. Furthermore, the crystalline and optical properties of COFs as well as the geometrical size and hydrophilicity inside the nanopores were reversibly controlled by alternating visible light irradiation and heat. Finally, methyl violet was used as the cargo molecules to be immobilized into the nanopores of COFs, which showed fast release under controlling of visible light.展开更多
基金the National Natural Science Foundation of China(Nos.21825109,21821002,21732006)the National Basic Research Program of China(No.2016YFA0202900)+2 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB20000000)the Chinese Academy of Sciences Key Research Program of Frontier Sciences(No.QYZDB-SSW-SLH016)the K.C.Wong Education Foundation,and the Science and Technology Commission of Shanghai Municipality(No.17JC1401200)is gratefully acknowledged.
文摘Main observation and conclusion Stereoselective isomerization of a-alkyl styrenes is accomplished using a new iron catalyst supported by phosphine-pyridine-oxazoline(PPO)ligand.The protocol provides an atom-efficient and operationally simple approach to trisubstituted alkenes in high yields with excellent regio-and stereoselectivities under mild conditions.The results of deuterium-labelling and radical trap experiments are consistent with an iron-hydride pathway involving reversible alkene insertion andβ-H elimination.
基金support from the Na-tional Natural Science Foundation of China(52203134,11772271,12272085)the Open Research Fund of Chengdu University of Traditional Chinese Medicine State Key Laboratory Southwestern Chinese Medicine Resource.
文摘Controlling properties of crystalline solids by light remains a challenge because the lack of intrinsic structural flexibility limits the necessary molecular mobility for photoisomerization. In this work, we reported a series of visible-light-responsive covalent organic frameworks (COFs) by introducing donor-acceptor Stenhouse adducts (DASAs) with various electron-withdrawing moieties via a post-modified strategy. The DASAs-functionalized COFs exhibit distorted honeycomb layered topology with long-range periodicity. The DASAs grafted on the skeletons are pointing into the nanopores of COFs, which weakens intermolecular aggregation and ensures sufficient free volume to undergo reversible isomerization between linear and cyclic states. Furthermore, the crystalline and optical properties of COFs as well as the geometrical size and hydrophilicity inside the nanopores were reversibly controlled by alternating visible light irradiation and heat. Finally, methyl violet was used as the cargo molecules to be immobilized into the nanopores of COFs, which showed fast release under controlling of visible light.
