Can tetrazole-functionalized ligands realize the role-control of Keggin-type POMs in hybrid frameworks?

Abstract

Two tetrazole-functionalized flexible ligands, bis(1-methyl-1H-tetrazol-5-yl)sulfane (bmps) and 5,5′-((2,2-bis(((1-methyl-1H-tetrazol-5-yl)thio)methyl)propane-1,3-diyl)bis(sulfanediyl))bis(1-methyl-1H-tetrazole) (bpbb), have been designed and used for the role-control of Keggin-type POMs in hybrid frameworks during self-assembly processes. With the isolation of two pairs of new compounds [Cu2(bmps)2(H2O)3(PMo12O40)]·(OH)·2.5H2O (1) and [Ag3(bmps)3(PMo12O40)]·H2O (3); [Cu4(bpbb)2Cl(PW12O40)] (2) and [Ag3(bpbb)(H2O)2(PW12O40)]·4H2O (4), we demonstrate here that it is feasible to achieve the role-control of POMs under hydrothermal conditions. In 1 and 3, the use of the simple and short bmps ligands favours the assembly of discrete and/or low-dimensional metal–organic moieties, and the POMs are utilised as building units to complete the construction of the whole structures. For 2 and 4, the large bpbb ligands facilitate the formation of porous metal–organic networks, in which the POMs are utilised as templates.