86709-65-1Relevant academic research and scientific papers
Preparation of praseodymium (III) chloranilate and the crystal structures of Pr2(C6Cl2O4) 3·8C2H5OH and Na3[C6H2O(OH) (SO3)2]·H2O
Riley, Paul E.,Haddad, Salim F.,Raymond, Kenneth N.
, p. 3090 - 3096 (2008/10/08)
The crystal structure of Pr2(C6Cl2O4) 3·8C2H5OH (1), a complex obtained by slow hydrolysis of o-chloranil (C6Cl4O2) in acidic ethanol solution, has been determined by single-crystal X-ray diffraction techniques with data collected by counter methods. The structure of Na3[C6H2O(OH)(SO3) 2]·H2O (2), the trianion of tiron, has also been determined by X-ray crystallography. Crystals of 1 form in triclinic space group P1 with a = 8.990 (1) A?, b = 10.503 (2) A?, c = 13.598 (1) A?, α = 99.02 (1)°, β = 91.50 (1)°, γ = 94.44 (1)°. The observed density of 1.643 g cm-3 is in agreement with the calculated value of 1.671 g cm-3 for one unit of Pr2(C6Cl2O4) 3·8C2H5OH per unit cell. The crystal structure is a three-dimensional network of alternating (C6Cl2O4)2- and Pr3+ ions in which the chloranilate rings lie about crystallographic inversion centers. The resulting coordination sphere about Pr3+ consists of six chloranilate oxygen atoms from three symmetry-independent chloranilate ions and three ethanol oxygen atoms (six of the eight ethanol molecules in the full formula - the remaining two are simply in the crystal lattice), arranged in an approximately tricapped trigonal-prismatic fashion. Full-matrix least-squares refinement of the structure has converged with R and Rw indices (on |F|) of 0.025 and 0.040 with use of 3057 symmetry-independent reflections with F02 > 3σ(F02). Crystals of 2 form from aqueous solution in orthorhombic space group Pnma with a = 16.018 (2) A?, b = 6.972 (2) A?, and c = 9.700 (1) A?. The [C6H2O(OH)(SO3)2]3- species exhibits rigorous Cs symmetry, with only the two symmetry-related oxygen atoms of each SO3 moiety lying out of the plane of the anion. There are no unusual aspects of the molecular geometry of 2. Full-matrix least-squares refinement of the structure has converged with R and Rw indices (on |F|) of 0.034 and 0.045 with use of the 805 observations with F02 > 3σ(F02).
