TiO₂nanoparticles decorated with Co-Schiff base-g-C₃N₄as an efficient photocatalyst for one-pot visible light-assisted synthesis of benzimidazoles

Abstract

The Co-g-C3N4-imine/TiO2 nanohybrid promotes different transformations in a one-pot reaction sequence: aerobic photooxidation of benzylic alcohols to aldehydes, and then the tandem synthesis of benzimidazoles.

Enhanced Visible-Light-Induced Photocatalytic Activity in M(III)Salophen-Decorated TiO2 Nanoparticles for Heterogeneous Degradation of Organic Dyes

“…16 To improve the photocatalytic ability and widen application fields, different preparation methods and a lot of modification methods have been tried, which have been reviewed in several articles. 15−17 Modification of TiO 2 with a Schiff base, 18,19 ascorbic acid (vitamin C), 20−23 g-C 3 N 4 , 24,25 dendrimer, 26,27 and boron 28 our modification methods and inspired by heme-containing enzymes, recently, we designed a new organosilicon linker (SAPy) by condensation of (3-oxopropyl)trimethoxysilane with 4-aminopyridine (Scheme 1) capable of coordinating to metal complexes of easily made salen-or salophen-type ligands with widespread applications in catalysis. 29 SAPy-functionalized maghemite nanoparticles (γ-Fe 2 O 3 ) were successfully used for the coordinative anchoring of M−salophen complexes (M = Fe, Mn) (M(III)(salophen)Cl@SAPy/Fe 2 O 3 ).…”

“…Besides, due to the rather fast recombination of electron–hole pairs, the quantum efficiencies of TiO 2 in energy conversions are rather poor, leading to the poor photoactivity of TiO 2 even in the UV region . To improve the photocatalytic ability and widen application fields, different preparation methods and a lot of modification methods have been tried, which have been reviewed in several articles. − Modification of TiO 2 with a Schiff base, , ascorbic acid (vitamin C), − g-C 3 N 4 , , dendrimer, , and boron is one of the efforts of our research groups in this area. To extend our modification methods and inspired by heme-containing enzymes, recently, we designed a new organosilicon linker (SAPy) by condensation of (3-oxopropyl)­trimethoxysilane with 4-aminopyridine (Scheme ) capable of coordinating to metal complexes of easily made salen- or salophen-type ligands with widespread applications in catalysis .…”

t‐BuONa‐Mediated Redox Condensation between o‐Nitroanilines and Benzyl Alcohols towards 2‐Phenyl Benzimidazoles under Transition‐Metal‐Free Conditions

“…Annulation of o-phenylenediamines with carbonyl compounds such as aldehydes and carboxylic acid derivatives may be the most employed strategies. [22][23][24][25] Ortho-nitroanilines and benzyl alcohols, which could be converted to two aforementioned starting materials by a redox process, are considered as precursors for the cyclization. [26][27][28][29] These synthetic approaches, however, are associated with inherent drawbacks including the requirement of transition metal catalysts, external oxidants, and stoichiometric amounts of acid or base, making them less preferable.…”

“…All the versatility and superiorities have continually appealed considerable efforts to access substituted benzimidazoles. Annulation of o ‐phenylenediamines with carbonyl compounds such as aldehydes and carboxylic acid derivatives may be the most employed strategies [22–25] . Ortho ‐nitroanilines and benzyl alcohols, which could be converted to two aforementioned starting materials by a redox process, are considered as precursors for the cyclization [26–29] .…”

Aerobic cross-dehydrogenative coupling of toluenes and o-phenylenediamines by flavin photocatalysis for the facile synthesis of benzimidazoles

“…Therefore, the sequential aerobic oxidative reaction of benzyl alcohols with o -phenylenediamines has been demonstrated as an alternative greener method that overcomes these challenges. 4 The most straightforward method of these involves aerobic cross-dehydrogenative coupling (CDC).…”