Two new bimetallic phosphates assembled from the 4-ring building units and influence of metal on the phase selectivity

Two new bimetallic phosphates [(CH₃)₂NH] _0.5[Zn_0.62Co_0.38PO₃OH] (ZnCoPO-CJ48) and [(CH₃)₂NH₂][Zn_2.3Mn _0.7(PO₄)₂(PO₃OH)]·H ₃O (ZnMnPO-CJ49) have been solvothermally synthesized in the similar reaction system. ZnCoPO-CJ48 is a layered zinco-cobalt phosphate with neutral framework, its structure is constructed by the connection of Zn(Co)O₄ and PO₃OH tetrahedra forming a novel 2-D sheet with 3- and 4-rings. The alternating connection of Zn(Mn)O₄ and PO₄/PO ₃OH tetrahedra results in the open framework of ZnMnPO-CJ49 with 16-ring extra-large channels. Notably, both compounds are featured by the 4-ring building units T₂P₂O₆(OH)₂ formed by the connection of two TO₄ tetrahedra and two PO₃OH tetrahedra. The 3-D structure of ZnMnPO-CJ49 can be viewed as the connection of zinc-manganese phosphate layers analogous to the layered structure of ZnCoPO-CJ48 by the 1-D edge-sharing 4-ring chains as the pillars. In this work, the synthetic conditions of these two compounds and the influence of metal on the phase selectivity have been discussed in detail.