Novel, ecofriendly, multifunctional luminescent (N^N)(P^P) copper(i) complexes: from OLEDs to photocatalytic CO2 reduction

The generation of clean energy and the achievement of efficient technologies for energy consumption are crucial for global sustainable development. In this context, low-cost ecofriendly copper complexes are very appealing, both for light-emitting devices and for photocatalysis. A new Xantphos Cu(i) complex bearing a 2,9-dimesityl-1,10-phenanthroline (1) has been prepared, with its X-ray structure showing the locking of its coordination sphere. Two related complexes with only one mesityl (2) or ortho-tolyl (3) substituent in position 2 of the phenanthroline have also been prepared. Although 1 is characterized by the highest luminescence quantum yield in solution due to the steric hindrance of two mesityl groups, complex 2 leads to the most efficient OLED (maximum luminance = 26 600 cd m−2; maximum EQE = 11.5%; maximum current efficiency = 32.5 cd A−1) and to the best performance for the photocatalytic reduction of CO2 to CO with a selectivity >99%.