A Giant Mo/Ta/W Ternary Mixed-Addenda Polyoxometalate with Efficient Photocatalytic Activity for Primary Amine Coupling

The reactivity and
properties of polyoxometalates (POMs) vary remarkably as a function
of the kind of addenda atoms, so the design and synthesis of new mixed-addenda
POMs is a promising approach for the further development of the POM-related
areas. In the present work, the first Mo/Ta/W ternary mixed-addenda
POM (NH4)41H7[K3(H2O)3(P2W15Ta3O62)6(Mo2O4CH3CO2)3(MoO3)2]·85H2O (1), which is composed of 6 {P2W15Ta3O62} linked by 3 {MoV2O4(OOCCH3)+} and 2 {MoVIO3} via 18 novel Mo–O–Ta bridges has been
synthesized. The precursor {P2W15Ta3}, which has lower redox potential, is crucial for the formation
of 1. The red-brown solid sample of 1 shows
strong absorption in the visible region. The visible-light responsive
charge transfer from benzylamine to 1 was observed experimentally. 1 was proved to be an efficient photocatalyst under simulated
sunlight (AM 1.5G) radiation for the oxidative coupling of primary
amines to imines using atmospheric O2.