Acetylene/Vinylene‐Bridged π‐Conjugated Covalent Triazine Polymers for Photocatalytic Aerobic Oxidation Reactions under Visible Light Irradiation

Abstract

Solar-driven photocatalytic chemical transformation provides a sustainable strategy to produce valuable feedstock, but designing photocatalysts with high efficiency remains challenging. Herein, two acetylene-or vinylene-bridged π-conjugated covalent triazine polymers, A-CTP-DPA and V-CTP-DPE, were successfully fabricated toward metal-free photocatalytic oxidation under visible light irradiation. Compared to the one without acetylene or vinylene bridge, both resulting polymers exhibited superior activity in photocatalytic selective oxidation of sulfides and oxidative coupling of amines; in particular, A-CTP-DPA delivered an optimal photocatalytic performance. The superior activity was attributed to the broadened spectral response range, effective separation, rapid transportation of photogenerated charge carriers, and abundant active sites for photogenerated electrons due to the existence of the acetylene bridge in the framework. This work highlights the potential of acetylene and vinylene bridges in tuning catalytic efficiency of organic semiconductors, providing a guideline for the design of efficient photocatalysts.

Donor–acceptor covalent organic framework promotes visible light-induced oxidative coupling of amines to imines in air

“…This suggests the possibility of excited electrons to reduce oxygen to form superoxide radical anions (O 2 ˙ − ). 44 Furthermore, a more negative CB potential of TpTt-COF implies the enhanced photocatalytic reducing capability. According to the equation E g = E VB − E CB , 45 the valence band (VB) potentials of TpTt-COF and TfTa-COF are calculated to be 1.95 V and 2.29 V vs. NHE, respectively.…”

“…Excited electrons which accumulated on triazine units transferred to O 2 molecules to form reactive O 2 ˙ − species ( I ); simultaneously, the holes left in the ketoenamine units took an electron from the α-carbon of benzylamine to form carbon centered radicals ( II ) and regenerate TpTt-COF . 44 Thanks to the synergistic effect of electron–hole pairs, the formed superoxide anion radical species O 2 ˙ − ( I ) could react with the benzylamine cationic radical ( II ) under mild conditions. The formed hydroperoxy (phenyl) methylamine intermediate ( III ) further converted into benzylimine ( IV ) and H 2 O 2 .…”

Sustainable application of calcium carbide residue as a filler for 3D printing materials

“…Modern industry needs acetylene as a key component for materials and chemicals production [1][2][3][4] . The scope of acetylene-derived products is very large: vinyl chloride [5][6][7] , acrylic acid [8][9][10] , butyndiol 11 , acetaldehyde [12][13][14] , and many others [15][16][17][18][19][20][21] . Manufacturing acetylene from calcium carbide is the current hydrocarbon-free method of industrial acetylene production.…”

Construction of core–shell MOF@COF hybrids with a Z-scheme heterojunction for efficient visible light photocatalysis

“…Aerobic oxidative coupling of amines plays a vital role in organic synthesis, since the resultant imines are the versatile building blocks for diverse chemical transformations. 25,26 Nevertheless, traditional thermo-catalysis systems often require high reaction temperatures (above 100 °C), which restricts their large-scale industrial applications. 27,28 Herein, we have constructed core-shell MOF@COF photocatalysts with a Z-scheme heterojunction to make the aerobic oxidative coupling of amines highly efficient at room temperature under visible light illumination.…”