A bi-polyoxometallate-based host–guest metal–organic framework†
Abstract
Anionic POMs prefer to bond with positive metal cations instead of neutral or negative organic ligands. Therefore, it is challenging to synthesize POM-based MOFs, let alone bi-POM-based host–guest MOFs. In this work, an unprecedented bi-POM-based host–guest MOF, Na[Ni(enMe)2]4[Ni(enMe)2(H2O)2]2{[Ni6(μ3-OH)3(enMe)3 (SIP)1.5(B-α-PW9O34)]2[H3PNiW11O40]}·5enMe·33H2O (1), with Ni6-capped [PW9O34] as the node of the host framework and Keggin-type [PNiW11O40] units as the guest was synthesized. 1 showed excellent chemical stability towards aqueous solutions of pH 2–12 at both ambient and boiling temperature, providing opportunities for its application in fresh water harvesting from air.