Nitrogen‐Doped TiO₂ Nanotubes‐Catalyzed Synthesis of Small D‐π‐A‐Type Knoevenagel Adducts and β‐Enaminones

Abstract

For the first time, interstitial nitrogen-doped TiO 2 nanotubes (INDTNTs) have been utilized as heterogeneous green catalysts for the synthesis of D-π-A-type Knoevenagel adducts (3) and βenaminones (6). Notable advantages of the present method include its wide substrate scope, low catalyst loading, avoiding the use of hazardous bases and solvents, products do not require chromatographic purification, high yields, catalyst reusability, etc. The optimized catalyst, INDTNTs-4 has been characterized by XRD, HRTEM, and XPS techniques. The photo-physical and electrochemical properties of D-π-A-type 3 and 6 have been evaluated. The study revealed that the colour tunability (cold white light to orange light) and the HOMO/ LUMO levels depend mainly on the presence of various electron donating and withdrawing groups on the aromatic/heteroaromatic rings of 3 and 6. The results indicate that the D-π-A-type 3 and 6 could be promising materials for the fabrication of optoelectronic devices.

Decatungstate‐Catalyzed Carbon‐Carbon Bond Formation Between Furfural and Electron‐Deficient Olefins

“…Additional references cited within the Supporting Information. [21][22][23][24][25][26][27][28][29][30][31][32][33][34]…”

t-BuOOH/TiO2 Photocatalytic System as a Convenient Peroxyl Radical Source at Room Temperature under Visible Light and Its Application for the CH-Peroxidation of Barbituric Acids

“…Visible light quanta have lower energy and, thus, are more promising for the development of selective and widely applicable photochemical synthetic methods based on suitable photocatalysts. Numerous attempts were directed to the photosensitization of titanium dioxide in the visible light region by another semiconductors [19][20][21][22], organic photocatalysts [23] or via element doping [24][25][26][27][28][29]. Another opportunity is to use organic compounds, especially bearing hydroxyl or carboxyl groups, such as phenols [30,31], salicylic acid [32,33], carboxylic acids [34][35][36] or N-hydroxyphthalimide [37,38], which can modify the TiO 2 surface to absorb visible light.…”