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 (NH 4 ) 41 H 7 [K 3 (H 2 O) 3 (P 2 W 15 Ta 3 O 62 ) 6 (Mo 2 O 4 CH 3 CO 2 ) 3 (MoO 3 ) 2 ]·85H 2 O ( 1 ), which is composed of 6 {P 2 W 15 Ta 3 O 62 } linked by 3 {Mo V 2 O 4 (OOCCH 3 ) + } and 2 {Mo VI O 3 } via 18 novel Mo–O–Ta bridges has been synthesized. The precursor {P 2 W 15 Ta 3 }, 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 O 2 .