HYBRID FRAMEWORK IRON(II) PHOSPHATE-OXALATES

摘要

Two inorganic-organic hybrid framework iron phosphate-oxalates, I, [N2C4H12]0.5[Fe2(HPO4)(C2O4)1.5] and II, [Fe2(OH2)PO4(C2O4)0.5], have been synthesized by hydrothermal means and the structures determined by X-ray crystallography. Crystal data: compound I, monoclinic, space group=P21/c (No. 14), a=7.569(2) angstroms, b=7.821(2) angstroms, c=18.033(4) angstroms, beta=98.8(1) degrees, V=1055.0(4) angstroms3, Z=4, M=382.8, Dcalc=2.41 g cm-3, MoKalpha, RF=0.02; compound II, monoclinic, spacegroup=P21/c (No. 14), a=10.240(1) b=6.375(3) angstroms, c=9.955(1) angstroms, beta=117.3(1) degrees, V=577.4(1) angstroms3, Z=4, M=268.7, Dcalc=3.09 g cm-3, MoKalpha, RF=0.03. These materials contain a high proportion of three-coordinated oxygens and [Fe2O9] dimeric units, besides other interesting structural features. The connectivity of Fe2O9 is entirely different in the two materials resulting in the formation of a continuous chain of Fe-O-Fe in II. The phosphate-oxalate containing the amine, I, forms well-defined channels. Magnetic susceptibility measurements show FeII to be in the high-spin state (t42ge2g) in II, and in the intermediate-spin state (t52ge1g) in I. 13 refs.