An Unusual Bismuth-Antimony-Europium Cluster-Imbedded Polyoxotungstate and Its Bidirectional Luminescence Detection.

An unprecedented aggregate formed by two bismuth-antimony-europium cluster-imbedded tungsten-oxo clusters and one Krebs-type polyoxotungstate linker [H 2 N(CH 3 ) 2 ] 14 Na 30 H 6 [W 4 O 10 ][B-β-BiW 9 O 33 ] 2 {[Bi 5.35 Sb 0.65 Eu 3 O 9 (H 2 O) 9 ][B-α-SbW 9 O 33 ] 3 } 2 ·124H 2 O ( 1 ) was prepared. The polyoxoanion skeleton of 1 contains a Krebs-type polyoxotungstate [W 4 O 10 ][B-β-BiW 9 O 33 ] 2 } 14- ({Bi 2 W 22 }) ( 1a ) as a linker that offers six active coordinate O atoms (two μ 3 -O and four μ 2 -O atoms) to grasp two Bi-Sb-Eu cluster-imbedded tungsten-oxo clusters {[Bi 5.35 Sb 0.65 Eu 3 O 9 (H 2 O) 9 ][B-α-SbW 9 O 33 ] 3 } 18- ( 1b ) through Bi-O-W and Sb-O-W bonds. 1b comprises an unprecedented nona-nuclearity Bi-Sb-Eu [Bi 5.35 Sb 0.65 Eu 3 O 9 (H 2 O) 9 ] 9+ cluster encircled by three trivacant [B-α-SbW 9 O 33 ] 9- segments in a triangular motif through Eu-O-W, Sb-O-W, and Bi-O-W linkages into a trilobal trimer. Moreover, a bidirectional detection method by using 1 as an effective luminescence probe was proposed to recognize both Mn 2+ and CO 3 2- through an "on-off-on" mode. 1 can be used as an "on-off" luminescent sensor to detect Mn 2+ ions in aqueous solution. The limit of detection was 0.05 μM (9 × 10 -6 mg L -1 ), which is much lower than the World Health Organization (WHO) guideline for Mn 2+ concentration in drinking water (0.05 mg L -1 ). Then the Mn 2+ -quenching system can be used as an "off-on" sensor to detect CO 3 2- in water system. This work provides a new research idea for the application of rare-earth-imbedded polyoxotungstate-based materials in the field of optical smart detection.