A Giant 3d-4f Polyoxometalate Super-Tetrahedron with High Proton Conductivity.

The assembly of gigantic heterometallic metal clusters remains a great challenge for synthetic chemistry. Herein, based on the slow release strategy of lanthanide ions and in situ formation of lacunary polyoxometalates, two giant 3d-4f polyoxometalate inorganic clusters [LaNi 12 W 35 Sb 3 P 3 O 139 (OH) 6 ] 23- (LaNi 12 ) and [La 10 Ni 48 W 140 Sb 16 P 12 O 568 (OH) 24 (H 2 O) 20 ] 86- (La 10 Ni 48 ) are obtained. The nanoscopic inorganic cluster La 10 Ni 48 possesses a super tetrahedron structure, which can be viewed as assembly from four LaNi 12 molecules encapsulating a central [La 6 (SbO 3 ) 4 (H 2 O) 20 ] 6+ octahedron core. This giant aesthetic La 10 Ni 48 tetrahedron containing 214 metal ions is the largest 3d-4f cluster reported thus far in polyoxometalate system. More interestingly, the LaNi 12 and La 10 Ni 48 display high stability in solution and La 10 Ni 48 displays excellent proton conductivity.