Synthesis of open-framework iron phosphates, [C 5N 2H 14] 2[Fe III2F 2(HPO 4) 4]·2H 2O and [C 5N 2H 14][Fe III4(H 2O) 4F 2(PO 4) 4], with one- and three-dimensional structures

Abstract

The hydrothermal syntheses and structures of two new open-framework iron phosphates, [C 5N 2H 14] 2[Fe III 2F 2(HPO 4) 4]·2H 2O, I, and [C 5N 2H 14][Fe III 4(H 2O) 4F 2(PO 4) 4], II, are presented. While the structure of I consist of FeO 4F 2 octahedra and HPO 4 terahedra linked to form one-dimensional structure, that of II consist of FeO 4(H 2O) 2, FeO 4(H 2O)F, FeO 4F 2 and PO 4 units connected to give rise to a three-dimensional structure. The structure of I resembles the naturally occurring mineral tancoite while II resembles the iron phosphate, ULM-12, [C 6N 2H 14][Fe 4(PO 4) 2F 2(H 2O) 3]. Magnetic susceptibility studies indicate anti-ferromagnetic behavior in both the compounds with T N=200 and 175 K for I and II, respectively. Crystal data: I, monoclinic, space group= P2 1/ n (no. 14). a=7.2261(6), b=16.5731(14), c=11.0847(10) Å, β=97.265(2)°, V=1316.8(2) Å 3, Z=4, ρ calc=1.952 g cm −1, μ (Mo Kα) =1.446 mm −1, R 1=0.0448 and w R 2=0.1141 for 1882 data [ I>2 σ( I)]; for II, monoclinic, space group= P2 1/ n (no. 14). a=9.9691(3), b=12.4013(3), c=17.3410(3) Å, β=103.762(1)°, V=2082.32(9) Å 3, Z=4, ρ calc=2.576 g cm −1, μ (Mo Kα) =3.162 mm −1, R 1=0.0510 and w R 2=0.1064 for 2979 data [ I>2 σ( I)].