Ce-mediated molecular tailoring on gigantic polyoxometalate {Mo₁₃₂} into half-closed {Ce₁₁Mo₉₆} for high proton...

Precise synthesis of polyoxometalates (POMs) is important for the fundamental understanding of the relationship between the structure and function of each building motif. However, it is a great challenge to realize the atomic-level tailoring of specific sites in POMs without altering the major framework. Herein, we report the case of Ce-mediated molecular tailoring on gigantic {Mo₁₃₂}, which has a closed structural motif involving a never seen {Mo₁₁₀} decamer. Such capped wheel {Mo₁₃₂} undergoes a quasi-isomerism with known {Mo₁₃₂} ball displaying different optical behaviors. Experiencing an 'Inner-On-Outer' binding process with the substituent of {Mo₂} reactive sites in {Mo₁₃₂}, the site-specific Ce ions drive the dissociation of {Mo₂^*} clipping sites and finally give rise to a predictable half-closed product {Ce₁₁Mo₉₆}. By virtue of the tailor-made open cavity, the {Ce₁₁Mo₉₆} achieves high proton conduction, nearly two orders of magnitude than that of {Mo₁₃₂}. This work offers a significant step toward the controllable assembly of POM clusters through a Ce-mediated molecular tailoring process for desirable properties.