J. Matt Farmer

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.

Syntheses, characterization, and structural analyses of several f-block isothiocyanatonitrato complexes

Reactions of tetra-n-butylammonium thiocyanate with lanthanide and uranyl nitrates yield complexes of the general type [(Bu)4N]x[M(NCS)y(NO3)z]. Samples of [(Bu)4N]2 [UO2(NCS)3( NO3)] (1), [(Bu)4N]3[Yb(NCS)4(NO3)2] (2), and [(Bu)4N]3[Nd(NCS)4(NO3)2rsqb; (3) were prepared from alcohol solutions. Crystallization of 1 occurs in the centrosymmetric monoclinic space group C2/c (No. 15) with a = 17.949(4) Å, b = 16.587(3) Å, c = 16.763(3) Å; β = 99.77(3)°; and Z = 4. The seven-coordinate uranium(VI) ion exhibits a pentagonal bipyramid coordination environment. Crystallization of 2 occurs in the centrosymmetric orthorhombic space group Pnnn (No. 48) with a = 12.530(2) Å, b = 12.9440(10) Å, c = 21.203(2) Å; Z = 2. The eight-coordinate ytterbium(III) ion expresses a dodecahedral coordination environment. Crystallization of 3 occurs in the noncentrosymmetric monoclinic space group Cc (No. 9) with a = 16.556(2) Å, b = 18.130(2) Å, c = 23.984(4) Å; Z = 4. The 10-coordinate neodymium(III) ion exhibits a dodecahedral coordination environment. Characterization includes physical property determinations, conoscopic studies, IR spectroscopic identifications, and UV spectral data. Details of the syntheses along with selected bond distances and angles are presented and discussed.

New synthesis of [RuH(CO)(PPh3)2L2][BF4] [L2 = 2py, 2(4-Mepy) or bpy] and X-ray crystal structure of [RuH(CO)(PPh3)2(4-Mepy)2][BF4]

Abstract The title compounds were prepared by reaction of RuH2(CO)(PPh3)3 with [C7H7][BF4] in the presence of excess pyridine, 4-picoline or 2,2′-bipyridine. The compounds were characterized by IR, 1 H and 31 P NMR, and X-ray crystallography (for the 4-Mepy complex). The spectroscopic data as well as the results of the X-ray crystal structure show that the complexes contain trans-oriented phosphines and cis-pyridines. Details of the structural content and selected bond distances and angles are internally consistent.

Synthesis, characterization, and structural analysis of (1:2) mixed cationic lanthanide potassium hexacyanoferrate (II) tetrahydrate

Abstract The crystal structural investigation of 1:2 ( La Pr ) KFe ( CN ) 6 ·4 H 2 O (I) has been determined from three-dimensional, single-crystal, X-ray diffraction data and refined by least-squares method to yield a final reliability (R) factor of 0.016 based on 363 unique reflections. The title compound crystallizes in the hexagonal space group P6 3 m (No. 176) with a = 7.381 (1), c = 13.855(3) A . For Z = 2, the calculated density is 2.354 Mg m−3 (exp., 2.347(4) Mg m−3). The coordination about the lanthanide central atoms is nine, and the geometric polyhedron is a tricapped trigonal prism (TTP). Cyanide bridging links the octahedral FeC6 groups to the 9-coordinated ( La Pr ) N 6 ( H 2 O ) 3 groups. The uncoordinated water molecule and the potassium ion occupy holes in the lattice along the threefold axis above and below the lanthanide atoms. Selected bond distances and angles are presented as well as discussions of the synthesis, TGA, IR, and digital SEM/EDS results, and other peripheral studies of I.

PREPARATION, CHARACTERIZATION, AND STRUCTURAL DETERMINATION OF CUBIC AND TRICLINIC TRIS (TETRA-N-BUTYLAMMONIUM) HEXAKISISOTHIOCYANATOSCANDATE (III)

Abstract Crystallographic structural refinements of the cubic ( I ) and triclinic ( II ) forms of [( n -C 4 H 9 ) 4 N] 3 [Sc(NCS) 6 ] have been carried out by means of three-dimensional single-crystal X-ray diffractometry. The cubic form crystallizes in space group Pa 3 (No. 205, Z =8) and the triclinic form crystallizes in P 1 (No. 2, Z =2). The respective lattice constants are a =24.630(4) A ( I ) and a =12.232(2), b =12.655(3), c =22.337(4) A, α =90.48(3), β =90.92(3), γ =96.73(3)° ( II ). A full-matrix least-squares refinement program yielded final reliability ( R ) factors of 0.088 and 0.061 based on 1078 and 4660 unique reflections, respectively. In both complexes, the molecular units consist of three separate cationic tetra- n -butylammonium groups and an independent hexakisisothiocyanatoscandium anionic group. The n -butyl ligands are coordinated tetrahedrally to the ammonium–nitrogen atoms and the near linear six thiocyanate ligands coordinate octahedrally through the nitrogen atoms to the scandium metal center atoms. Characterizations include physical property determinations and spectrometric identifications employing I.R., 1 H and 13 C NMR and X-ray powder analyses. Selected bond distances and angles as well as syntheses and peripheral studies are presented and discussed.

Structure of adamantan-1-ammonium 1-adamantanecarboxylate

Adamantan-1-ammonium 1-adamantanecarboxylate, C21H33NO2 (I) is a novel dispiro-type compound. Aminoadamantane derivatives, in which the spiro carbon atoms are part of heterocyclic rings, are of potential interest as biological active substances and antiviral agents. Complex (I) crystallizes in the centrosymmetric space group C2/c (No. 15) with eight molecules in the unit cell with a = 25.227(4), b = 6.527(1), c = 22.489(4) Å, and β = 90.75(1)°. The two spiro units are a 1-adamantylammonium cation and a 1-adamantane carbonyloxy anion. The complex units are stabilized by a network of intermolecular carbonyloxy-to-amine hydrogen bonding and van der Waals cohesive forces. Germane bond lengths are: C—N = 1.479(9) and C—O (mean) = 1.25(2) Å.

Synthesis and structural investigation of tris(tetra-n-butylammonium)diisothiocyanatotetranitratocerinate (III)

Abstract The X-ray structural investigation of [(n-C4H9)N]3[Ce(NCS)2(NO34] (I) has been carried out by means of three-dimensional singlecrystal diffractometry. The title compound I crystallizes in space group Cc (No. 9, Z = 4). The lattice constants are a = 16.577(3), b = 18.136(4), c = 24.006(5) A , β = 91.31(3) ° . A full-matrix least-squares refinement yielded a final reliability (R) factor of 0.062 based on 2859 unique reflections. The coordination about the cerium central atom is ten and the geometric polyhedron is bicapped dodecahedral. The molecules in the crystal lattice are held together by van der Waals forces. Selected bond distances and angles are presented and discussed as well as synthesis and peripheral studies.

STRUCTURAL ANALYSES OF TWO MIXED CATIONIC LANTHANIDE POTASSIUM HEXACYANOFERRATE(II) TETRAHYDRATES

Abstract The crystal structural investigations of 1 : 1 (La/Nd)KFe(CN)6 4H2O (I) and 1:1 (Pr/Nd) KFe(CN)6·4H2O (II) have been determined using three-dimensional, single-crystal, X-ray diffraction data and refined by least-squares to yield final reliability (R) factors of 0.0180 and 0.020 based on 358 and 343 unique reflections, respectively. I and II crystallize in the hexagonal space group P63/m (No. 176) with a = 7.371(1), c= 13.833(3)Å for I and a = 7.362(1), c= 13.799(3) A for II. For Z = 2, the respective calculated densities are 2.371 and 2.388 mgm−3 [exp., 2.369(4) and 2.382(4)mgm−3]. The coordination about the lanthanide central ions in both I and II is nine, and the geometric polyhedra are tricapped trigonal prisms (TTP). Cyanide bridging links the octahedral FeC6 groups to the nine-coordinated (Ln/Nd)N6(H2O)3 groups. The noncoordinated water molecule and the potassium ion occupy holes in the lattice along the three-fold axis above and below the lanthanide ions. Selected bond distances and angles are presented as well as discussions of the synthesis, TGA, IR, and digital SEM/EDS results, and other peripheral studies of I and II.

SYNTHESIS, CHARACTERIZATION, AND STRUCTURAL ANALYSES OF THREE HIGH-COORDINATION TETRA-N-BUTYLAMMONIUM LANTHANIDE(III) COMPLEXES

Reactions of tetra-n-butylammonium thiocyanate with the appropriate lanthanide nitrate polyhydrate yield complexes of the general type [(n-C 4 H 9 ) 4 N] 3 [Ln(NCS) x (NO 3 ) y ]. [(n-C 4 H 9 ) 4 N] 3 [Pr(NCS) 2 (NO 3 ) 4 ] ( I ), [(n-C 4 H 9 ) 4 N] 3 [Nd(NCS) 4 (NO 3 ) 2 ] ( II ), and [(n-C 4 H 9 ) 4 N] 3 [Dy(NCS) 4 (NO 3 ) 2 ] ( III ) were crystallized from ethanol and characterized by single-crystal X-ray crystallography, IR spectroscopy, and other physical determinations. The coordination about the central lanthanide ion varied. For complex I , the geometric polyhedron is a bicapped square antiprism ( D 4 d ), while those for complexes II and III are best described as a dodecahedral prism ( D 2 d ). Details of the synthesis and selected bond distances and angles are presented and discussed.

X-RAY CRYSTALLOGRAPHIC INVESTIGATIONS AND CHARACTERIZATIONS OF THREE MIXED ANIONIC HEXACYANO COMPLEXES

Abstract The mixed anionic complexes, Cd3 1l[(CrIII/IrIII)(CN)6]2 13H2O, Co3 11[(CoIII/IrIII)(CN)6]2-13H2O, and Pd3 II[(CrIII/IrIII)(CN)6]2 13H2O, crystallize in the cubic centrosymmetric space group Fm3m (No. 225) with αo= 10.884(1), 10.396(1), and 10.455(2)A, respectively. The disordered structures contain 11/3 molecules in the unit cell. Full-matrix least-squares refinements yielded final reliability (R) index factors of 0.040, 0.050, and 0.069 with ‚goodness-of-fit‘ (GOF, ∑2) values of 1.26, 1.25, and 1.11, respectively. All metal atoms in each compound are six-coordinate octahedral and the cationic divalent metal atoms are linked to the (1:1) mixed trivalent metal atoms by cyanide bridging. Networks of hydrogen-bonding are setup within cavities of the crystal lattices (created by molecular disordering). Characterization of each hexacyano complex includes physical property determinations, conoscopic studies, I. R. spectroscopic identifications, and thermal gravimetric analyses (TGA). Selective bond di...