SYNTHESIS, CHARACTERIZATION AND STRUCTURAL ANALYSES OF THREE LANTHANIDE CYANIDE-BRIDGED COMPLEXES

Abstract

Three lanthanide (Ln) complexes (DMF)4(H2O)3LnFe(CN)6 · H2O, where Ln = Er, Yb, and Lu, were structurally determined by means of three-dimensional single-crystal X-ray diffraction analysis. These systems crystallize in the centrosymmetric monoclinic space group P21/c (No. 14) with Z = 4 and respective lattice constants of a = 13.956(2), 13.952(1), 13.937(3); b = 8.867(4), 8.864(1), 8.862(2); c = 24.857(3), 24.812(2), 24.770(5) Å; and β = 96.30(1)°, 96.33(1)°, 96.30(3)°. Final least-squares full-matrix refinements based on 3499, 3367, and 2555 unique reflections yielded reliability (R) index factors of 0.071, 0.051, and 0.032, respectively. In each complex, the coordination about the central Ln ion is eight in a square-antiprism arrangement and the coordination about the Fe ions is six, oriented octahedrally. Cyanide bridging links the Ln ions to the FeC6 groups. Molecules in the crystal lattice of each complex are held together by van der Waals forces and a network of hydrogen bonding. Characterization includes physical property determinations, conoscopical studies, thermal gravimetric analyses, and IR spectrometric identifications. Selected bond lengths and angles are tabularized and a synthesis of these compounds is presented.