Assembly of Four Ternary Polyoxometalate Aggregates by Integrating Presynthesized {XW9Nb3O40} (X = Si/Ge) Units Using Molybdenum-Oxo Clusters

Inorg Chem. 2024 Dec 24. doi: 10.1021/acs.inorgchem.4c04359. Online ahead of print.

Abstract

Polyoxometalates (POMs) have good potential for applications in different fields, including conducting materials, optics, and electrocatalysis. Of particular significance is the synthesis and development of addendum POMs. Molybdenum-oxo clusters, which are renowned for their diverse structures and electronic properties, were utilized to facilitate the synthesis of innovative materials. Herein, we employed presynthesized {XW9 Nb3O40} (X= Si/Ge) polyanions as secondary building units and different molybdenum-oxo clusters as linkers. Four new addendum POMs were constructed, including two dimeric compounds Cs10[H2(SiW9Nb3O40)2(Mo2O4C2O4)]·19H2O (1) and Cs8[H4(GeW9Nb3O40)2(Mo2O4C2O4)]·17H2O (2), and two tetrameric compounds Cs15(NH4)[(SiW9Nb3O40)4(Mo4O6)]·42H2O (3) and Cs10K5[H(GeW9Nb3O40)4(Mo4O6)]·39H2O (4). Notably, this is the first report of Mo/W/Nb ternary mixed-addendum POMs. In addition, compounds 3 and 4 facilitate the transfer of protons through extended hydrogen-bonding networks with conductivity values of 1.16 × 10-2 and 7.73 × 10-3 S·cm-1 at 85 °C and 98% relative humidity, respectively. Furthermore, no discernible decline in conductivity was noted over the course of 10 h.