title: Visible light mediated cyclization of tertiary anilines with maleimides using nickel(II) oxide surface-modified titanium dioxide catalyst.
abstract: Surface-modified titanium dioxides by highly dispersed NiO particles have an extended absorption in the visible light region and a reduced hole-electron pair recombination than unmodified TiO2. They have now been successfully applied as highly active heterogeneous photocatalysts in the visible light mediated direct cyclization of tertiary anilines with maleimides to give tetrahydroquinoline products in moderate to high yields at ambient temperature. In contrast with unmodified titanium dioxide catalysts that are conventionally used in a stoichiometric amount in combination with UVA light, only a catalytic amount (1 mol %) of the surface-modified TiO2 catalyst is needed along with visible light to efficiently catalyze the reaction. Compared with transition-metal complexes such as Ru(bpy)3Cl2 or Ir(ppy)2(dtbbpy)PF6, advantages of these surface-modified titanium dioxides as photocatalyst include high catalytic activity, low cost, ease of recovering, and being able to be used for at least nine times without significant decay of catalytic activity.
authors: Key Laboratory of Clean Dyeing and Finishing Technology of Zhejiang Province, School of Chemistry and Chemical Engineering, Shaoxing University , Shaoxing 312000, China.
authors: Jian
authors: J
authors: Tang
authors: Günter
authors: G
authors: Grampp
authors: Yun
authors: Y
authors: Liu
authors: Bing-Xiang
authors: BX
authors: Wang
authors: Fei-Fei
authors: FF
authors: Tao
authors: Li-Jun
authors: LJ
authors: Wang
authors: Xue-Zheng
authors: XZ
authors: Liang
authors: Hui-Quan
authors: HQ
authors: Xiao
authors: Yong-Miao
authors: YM
authors: Shen
mesh_terms: D000814:Aniline Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D003500:Cyclization; D008027:Light; D008301:Maleimides / Q000138:chemical synthesis* / Q000737:chemistry; D009532:Nickel / Q000737:chemistry*; D010777:Photochemistry; D014025:Titanium / Q000737:chemistry*
chemical_list: D000814:Aniline Compounds; D008301:Maleimides; C009495:titanium dioxide; D009532:Nickel; C028007:nickel monoxide; D014025:Titanium; C023650:aniline