Thiophene-embedded conjugated microporous polymers for photocatalysis

Abstract

<p>“Bottom-up” embedding of thiophene derivatives into CMPs for highly efficient heterogeneous photocatalysis is reported.</p>

Photochemical Synthesis of Benzimidazoles from Diamines and Aldehydes

“…Linear aldehydes both of smaller and larger chains reacted effectively (Scheme 4, 19-22). Branched aliphatic aldehydes led to the desired product in good yields (Scheme 4,(23)(24)(25)(26)(27). This protocol could be extended into different diamines which, when reacting with benzaldehyde, afforded benzimidazoles in moderate yields (Scheme 4, 28 and 29).…”

“…Recently, Li and coworkers utilized an organic dye, fluorescein, as the photocatalyst to synthesize benzimidazoles via Blue LED irradiation (Scheme 2, F ) [20] . Photochemistry has provided interesting approaches for the synthesis of benzimidazoles from diamines and aldehydes, either employing tetrazines, [21] or heterogeneous photocatalytic systems [22–26] . Finally, a DMF‐water (9 : 1) solvent system at 80 °C has been shown to promote the synthesis of benzimidazoles [27] .…”

“…[20] Photochemistry has provided interesting approaches for the synthesis of benzimidazoles from diamines and aldehydes, either employing tetrazines, [21] or heterogeneous photocatalytic systems. [22][23][24][25][26] Finally, a DMF-water (9 : 1) solvent system at 80°C has been shown to promote the synthesis of benzimidazoles. [27] Limitations of these methods are the harsh reaction conditions, the catalyst preparation, the cost and effect on the environment and the limited substrate scope, especially when aldehydes bearing aliphatic chains are employed.…”

Progress in Photocatalytic Synthesis of Benzimidazoles

“…Two photoactive thiophene derivatives, 2,2’‐bithiophene (BTP) and thieno[3,2b]thiophene (TBTP), have been incorporated into CMP based on trigeminal rigid monomer 1,3,5‐tris(4,5,5‐tetramethyl‐1,3,2‐dioxaborolan‐2‐yl)benzene (TTDB) in An's [22] work by a one‐step Suzuki–Miyaura coupling reaction (Scheme 4a). The activity test indicated that the performance of BTP‐CMP was better than TBTP‐CMP for synthesis of BIs, and the optimal molar loading amount of BTP was 6.2 %.…”

“… Conjugated microporous polymers photocatalyst based on (a) BTP and TBTP designed by An et al [22] . and (b) benzotrithiophene (BTT) building blocks designed by Han et al.…”