Investigation Of Catalytic Behavior Research Articles

Organometallic titanocene complex as highly efficient bifunctional catalyst for intramolecular Mannich reaction

Bifunctional catalysts bearing two catalytic sites, Lewis acidic organometallic titanocene and Brønsted acidic COOH, have been assembled in situ from Cp2TiCl2 with carboxylic acid ligands, showing high catalytic activity over an intramolecular Mannich reaction towards synthesis of 2‐aryl‐2,3‐dihydroquinolin‐4(1H)‐ones. The determination of the bifunctional catalyst Cp2Ti(C8H4NO6)2 was elucidated by single X‐ray HR‐MS and investigation of catalytic behavior. In particular, masking the Brønsted acidic COOH catalytic site with dormant COOMe lowered the reaction yield greatly, indicating that two catalytic sites work together to maintain high catalytic efficiency.

Investigation of Solvent-Dependent Catalytic Behavior of a Hydrophobic Guest Artificial Glutathione Peroxidase

The investigation of the catalytic behavior of a hydrophobic guest artificial glutathione peroxidase (GPx) (ADA-Te-ADA) was carried out employing H2O2 and 3-carboxyl-4-nitrobenzenethiolas (TNB) as substrates. The relation between the catalytic rate of ADA-Te-ADA and the property of solvent used in the determination of catalytic activity was revealed. Typically, the co-solvents including ethanol, DMSO, DMF and CH3CN were employed in the determination of catalytic rates. It indicated that ADA-Te-ADA exhibited the typical solvent-dependent catalytic behavior. Especially, the higher catalytic rate was observed when polar protic solvent (ethanol) was used compared with other co-solvents. It suggested that polar protic solvent was the appropriate co-solvent for the assay of catalytic activity of hydrophobic artificial GPx. Additionally, the strong polarity of polar aprotic solvent plays an important role in the enhancement of GPx catalytic activity. This study bodes well for the understanding of the catalytic behavior of hydrophobic guest artificial GPx.