Dual Photoactive Species in CuPd for Light-switched Homo-coupling of Alkynes in Anaerobic and Base Free Condition

Graphical Utilizing CuPd alloy on C 3 N 4 as catalyst, the photoswitched coupling of alkynes under anaerobic and alkali-free conditions was achieved. The dual photoactive species (coppr phenylacetylide intermediate and the LSPR effect of Cu) and the interface between Cu and Pd is essential for efficiently swtiching the reaction pathway. Various ratios of CuPd alloy are loaded on C 3 N 4 and utilized as efficient photocatalyst for the light-switched homo-coupling of alkynes in anaerobic and base free condition. For the model phenylacetylene reactant, the light-irradiation promotes the reaction rate from 36.9 % to 99.9 % and the selectivity of 1,3-diynes from 0 % to 68.7 %. Different supports, solvents and the induction period of the prepared samples show influence on the activity. The action spectra with different light wavelengths demonstrate that both copper phenylacetylide intermediate formed during the reaction and the localized surface plasmon resonance (LSPR) effect of the copper in CuPd alloy are the photoactive species. Through the control experiments, it confirms that these dual photoactive species and the interface between Cu and Pd are essential for efficient light-switching reaction pathway.