[Zn(H2PO4)4]2− clusters and ∞[Zn2(HPO4)3(H2PO4)2]4− layers in two new zinc phosphates templated by [H2(4-amino-2.2.6.6-tetramethylpiperidine)]2+ cations

Two zinc phosphates (ZnPO), [H2(N2C9H20)]·[Zn(H2PO4)4] (I) and [H2(N2C9H20)]2·[Zn2(HPO4)3(H2PO4)2]·H2O (II), are synthesized under hydrothermal conditions using 4-amino-2.2.6.6-tetramethylpiperidine as organic template. I crystallizes in image space group with image, image, image, image, image, image, image and image. Its structure, refined to image and image for 4279 independent reflections, consists of [Zn(H2PO4)4]2− clusters held together through strong hydrogen bonds to form pseudo-layers between which the doubly protonated amine molecules are inserted. II is monoclinic, C2, with image, image, image, image, image and image (image, image, 2477 independent reflections). The structure of II consists of ∞[Zn2(HPO4)3(H2PO4)2]4− inorganic (2D) layers built up from vertex-sharing [ZnO4] and [(H2/H)PO4] tetrahedra. Organic cations and water molecules ensure the connection between these layers via hydrogen bonds. It is shown that numerous (1D), (2D), e.g., [H2(N2C9H20)]2·[Zn2(HPO4)3(H2PO4)2]·H2O, and (3D) (ZnPO) result from the condensation of the [Zn(H2PO4)4]2− clusters.