A dendritic TiO2–Co(ii) nanocomposite based on the melamine catalyzed one-pot aerobic photocatalytic synthesis of benzimidazoles. (3rd April 2018)

• Record Type: Journal Article
• Authors: Eskandari, Ameneh; Jafarpour, Maasoumeh; Rezaeifard, Abdolreza; Salimi, Mehri
• Is Part Of: New journal of chemistry. Volume 42:Number 8(2018)
• Page Start: 6449
• Page End: 6456
• Publication Date: 2018-04-03
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/c8nj00351c
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : The nanocrystalline TiO2 surface modified with cobalt melamine dendrimer amine complex under ultrasonic agitation produced a novel low band-gap photocatalyst (Co(ii )–TD@TiO2 ). This catalyst system involves photooxidation of alcohols to aldehydes followed by cyclocondensation with 1, 2-phenylenediamine to afford benzimidazoles in one-pot operation with good to excellent yield. Abstract : A novel heterogeneous visible light active nanophotocatalyst was produced via modification of a nanocrystalline TiO2 surface with a cobalt(ii ) complex of melamine dendrimer under ultrasonic agitation, and was characterized by different techniques such as FT-IR, XPS, EDS, ICP-AES, TGA, DRS, UV-Vis, TEM and SEM. A red-shift of the band-edge and a significant reduction of the band-gap (2.7 eV) were revealed by UV-DRS. The as-prepared dendritic nanophotocatalyst significantly promoted the aerobic synthesis of benzimidazole derivatives with biological and pharmaceutical interest by a one-pot three-step process from the photooxidation of alcohols to aldehydes followed by cyclocondensation with 1, 2-phenylenediamine with good to excellent yield. This process has the potential to enable a more sustainable benzimidazole synthesis. The combination of photocatalytic and catalytic reactions presented here may help to develop a new strategy towards the development of photocatalysis-based organic synthesis.