Template Effect of Chain-Type Polyamines on Pore Augmentation: Five Open-Framework Zinc Phosphates with 16-Ring Channels

Five new zinc phosphates with differently unique 3D framework topologies, (H3dien)[Zn3(HPO4)3(PO4)] (1), (H2dien)1.5[Zn3(HPO4)3(PO4)] (2), (H3dien)[Zn3(H2PO4)(HPO4)(PO4)2] (3), (H3dien)[Zn3(HPO4)3(PO4)]·1.5H2O (4), and (H4tepa)0.5[Zn2.5(HPO4)2(PO4)]·1.5H2O (5), where dien = H2NC2H4NHC2H4NH2 and tepa = H2N(C2H4NH)3C2H4NH2, have been synthesized under mild hydrothermal or solvothermal conditions and characterized by single-crystal X-ray diffraction, thermal analysis, solid-state NMR, UV–vis, or photoluminescence spectroscopy. Both the 7-atom-skeleton-long dien and the 13-atom-skeleton-long tepa have created 16-membered ring (16R) channels as a common feature in structures 1–5. Their inorganic frameworks are built up with tetrahedra of ZnO4, PO4, and HPO4 (plus H2PO4 in 3) and may all be described as constructed from two-dimensional nets and one- or zero-dimensional units as linkers. Compounds 1–4 have the same Zn/P ratio but possess varied amount of nonframework volume. They are the first examples with dien as template in extra-large-channel structures of zincophosphates. In comparison, the framework of 5 contains a higher value in Zn/P and larger nonframework volume than that in the 24R-channel structure of ND-1. The 16R channels in 1 and 2 are one-dimensional while those in 3, 4, and 5 are unprecedentedly two-dimensional. In this paper, the synthesis, thermal property, NMR, reflectance UV–vis absorption, and photoluminescence study of 1–5 are described; framework topologies, structure relationship, the charge and location of templates, and channel characteristic vs nonframework volume are discussed.