The synthesis and crystal structure of a new open-framework zincophosphate UiO-17
Abstract
A novel three-dimensional open-framework zincophosphate 2[N2C4H12]2+[Zn7(H2O)2(PO4)6]4– has been synthesised hydrothermally, and characterised by powder and single crystal X-ray diffraction, thermogravimetric analysis and solid state 31P MAS and 13C CP MAS NMR spectroscopy. The compound crystallises in the monoclinic space group C2/c with a = 16.134(3), b = 8.241(2), c = 22.860(5) Å, β = 104.05(3)°, V = 2948.4(10) Å3 and Z = 4. The open framework contains a two-dimensional staggered eight-membered ring channel system running along [001] and [011] in which diprotonated piperazinium cations reside. The framework consists of ZnO4 and PO4 tetrahedral units, in addition there are ZnO4(H2O) trigonal bipyramids which together with Zn–O–Zn bonding lead to an interrupted framework rather than alternating ZnO4 and PO4 linkages. The framework is an example of symmetry matching between template and framework as a symmetry element of piperazine constrains the framework structure.