{HPO3} and {WO4} Simultaneously Induce the Assembly of Tri-Ln(III)-Incorporated Antimonotungstates and Their Photoluminescence Behaviors.

A double template agent strategy has been adopted to prepare a group of triacetate-adorned tri-Ln(III)-incorporated trimeric antimonotungstates (AMTs) K3Na21H[Ln3(CH3COO)3(HPO3)(WO4)][B-α-SbW9O33]3·36H2O [Ln = Eu3+ (1), Dy3+ (2), Ho3+ (3), or Er3+ (4)] in a CH3COOH-CH3COONa buffer system. Therein, H3PO3 and Na2WO4·2H2O have been, respectively, transformed into the capped {HPO3} and {WO4} tetrahedra during the assembly process, which are situated at the center of polyoxoanions of 1-4 and simultaneously perform as structure-directing templates to induce the assembly of 1-4. The hexahedral configuration supramolecular stacking is the same as the shape of a crystal of 1, which illustrates that the supramolecular stacking mode plays a significant role in forming the crystal shape of 1-4. Under the Ln3+ f-f excitation, the photoluminescence behaviors involving the emission spectrograms and fluorescence decay curves of 1-4 were systematically researched. The modulation of the excitation wavelength has realized the emission color tuning from blue to red, blue to green, blue to yellow, and green to yellow for 1-4. On the basis of the excitation of O → W charge transfer (OWCT), the energy-transfer procedure from AMT units to Eu3+ centers in 1 is mainly accomplished in the form of energy reabsorption. This work proposes a typical case for the construction of a new type of AMT clusters by using the double template agent strategy and confirms the great potential of Ln-containing AMTs in optic applications.