Three-dimensional open-framework zinc phosphates with the structure-directing organic amines acting as ligands

Abstract

Two new three-dimensional zinc phosphates I, [NH(CH₂)₂NH₂(CH₂)₂NH₃]²⁺[Zn₅(PO₄)₄]^2-, and II, [CN₅H₆]⁺[Zn₂(PO₄)(HPO₄)]^-, where the structure-directing organic amine acts as a ligand, have been synthesized hydrothermally. Crystal data for I: a=27.071(2), b=5.215(1), c=17.920(1) Å, β=130.3(1)°; U=1930.9(3) ų; space group=Cc (no. 9); Z=4; M=811.01; D_calc=2.789 g cm^-3; MoKα and for II: a=8.089(1), b=12.771(1), c=10.067(1) Å, β=105.3(1)°; U=1000.3(2) ų; space group=P2₁/n (no. 14); Z=4; M=409.8; D_calc=2.713 g cm^-3; MoKα. Compound I is novel in the sense that it is dominated by the presence of a large number of three-coordinated oxygen atoms (25%), leading to the formation of infinite Zn–O–Zn chains. The presence of a distorted bipyramidal ZnO₃N₂ unit as well as a 2-membered ring in II is noteworthy. These structures are formed by the networking of ZnO₄, ZnO₃N, PO₄ and ZnO₃N₂ moieties, leading to the formation of three-dimensional structures possessing channels with I forming a 10-membered one-dimensional channel system and II forming two 8-membered channels.