Organic-inorganic hybrids assembled from plenary Keggin-type germanotungstate units and 3d-4f heterometal clusters

Two kinds of organic-inorganic 3d-4f heterometal hybrids based on plenary α-Keggin-type germanotungstates [Cu2(H2O)3(PA)3] [Ln0.5Na0.5Cu2(H2O)12(PA)3][α-GeW12O40]·5H2O [Ln = La3+ (1), Ce3+ (2)] and [Cu2(H2O)2(PA)3][Cu(PA)2][Ln(H2O)7][α-GeW12O40]·7H2O [Ln = Tb3+ (3), Dy3+ (4), HPA = 2-picolinic acid] were prepared via the strategy of combining an in situ assembly reaction and stepwise synthesis in the aqueous solution. The most remarkable structural characteristic of 1-2 is that neighboring structural units are connected into a 1-D chain alignment by the bridging di-copper [Cu2(H2O)3(PA)3]+ subunits, whereas the most outstanding structural feature of 3-4 is that neighboring structural units are interconnected to generate a zigzag 1-D chain alignment by the bimetallic bridging [Cu2(H2O)3(PA)3]+ subunits, and then adjacent zigzag 1-D chains are integrated into a fascinating 2-D sheet structure by heterobimetallic bridging {Tb(H2O)7[Cu(PA)2]0.5}3+ subunits and [Cu(PA)2] groups. As far as we know, 1-4 represent the first examples of plenary Keggin heterometal germanotungstates including organic 3d-4f heterometal subunits so far. The electrochemical sensing properties towards the detection of Acetaminophen of 1/3@CMWCNT-Nafion/GCE electrochemical sensors were investigated, showing that 1/3@CMWCNT-Nafion/GCE electrochemical sensors exhibit good stability and good sensing performance towards AC detection.