Design and Synthesis of Molybdenum Red Cluster { Mo₄₉ } by Building Block-Directed Assembly for Proton Conduction

Abstract

Highly reduced molybdenum red(MR) clusters have emerged as a new type of polyoxomolybdates(POMos) and showed great potential as electron/proton reservoirs for energy conversion and storage, as well as for catalysis. However, the limited structural diversity of MR clusters significantly hinders further exploration of their potential as functional materials. Herein, we describe the synthesis of a novel highly reduced MR cluster {Mo₄₉}(compound 1) based on rational assembly of a variety of basic building blocks(BBs). In addition to the well-established BBs found in the family of MR clusters, the unique tetrahedral {Mo^VI₄} BB plays a key role in directing the assembly to afford trigonal pyramid-like structure of compound 1, which consists of 49 Mo and 148 O atoms with a high reduction degree of 73%. Moreover, at 80 ℃ and 98% relative humidity(RH), the pellet sample of compound 1 displays good proton conductivity of 7.88×10^-3 S/cm owing to the efficient hydrogen-bonded network built from the surface oxygen atoms, protons and guest water molecules. This research offers new insights into the assembly and synthesis of MR clusters through a BB strategy and manifests their significant potential for advanced applications.

Keywords

polyoxomolybdate(POMo) / highly reduced cluster / building block(BB) / proton conductivity

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Funding

National Natural Science Foundation of China(92161111)

National Natural Science Foundation of China(21901038)

Program for Professor of Special Appointment(Eastern Scholar) at Shanghai Institutions of Higher Learning)

Program for Professor of Special Appointment(China)

International Cooperation Fund of Science and Technology Commission of Shanghai Municipality, China(21130750100)