{HPO<sub>3</sub>} and {WO<sub>4</sub>} Simultaneously Induce the Assembly of Tri-Ln(III)-Incorporated Antimonotungstates and Their Photoluminescence Behaviors
Xin Xu, Xiaoyi Liu, Dan Wang, Xuejun Liu, Lijuan Chen, Junwei Zhao
Abstract
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.