Wenqi Chen

Crystal structure of cyclooctatetraenylpotassium, C8H8K2•(OC4H8)3

Abstract Crystals of C 8 H 8 K 2 ·3THF were prepared by the reaction of cyclooctatetraene with metallic potassium in tetrahydrofuran (THF). X-ray diffraction data were collected on a four-circle diffractometer at −80°C. The compound crystallizes in the triclinic space group P 1 with a 10.263(3), b 13.157(4), c 9.443(3) A, α 87.51(2), β 115.93(2), γ 76.81(2)°, Z = 2. The structure was solved by heavy-atom methods and refined by least-squares to a final R value of 0.051. The cyclooctatetraene with crystallographic centre of symmetry is planar and bonded on either side to two equivalent K + ions. The adjacent non-equivalent K + ions are connected by two oxygen bridges from THF molecules, and are catenated.

Crystal structure of cyclopentadienylneodymium dichloride

Abstract The compound η 5 -C 5 H 5 NdCl 2 · 3THF was successfully prepared from NaC 5 H 5 and NdCl 3 in tetrahydrofuran (THF). Methods preventing disproportionation are discussed. X-ray diffraction data of the compound were collected at low temperature (about 210 K). Crystals belong to monoclinic space group P 2 1 / n with a 7.864(3), b 17.198(7), c 15.212(5) A, β = 94.46(3)°, Z = 4. 1791 reflections were considered observed. The structure was solved by heavy-atom methods. Least-squares refinement converged to a final value of R = 0.049.

Syntheses and crystal structures of triindenyllanthanide complexes (η5-C9H7)3Ln · OC4H8 (Ln Nd, Gd, Er)

The complexes named in the title (eta-5-C9H7)3Ln.OC4H8 (Ln = Nd, Gd, Er) were synthesized by the reaction of anhydrous lanthanide trichlorides with indenyl potassium and cyclooctadienyl potassium (1:2:1 molar ratio) in THF. The complexes were characterized by elemental analysis, infrared and H-1-NMR spectroscopy, and mass spectrometry. In addition, the crystal structures of (eta-5-C9H7)3Nd.OC4H8 (1) and (eta-5-C9H7)3Gd.OC4H8 (2) were determined by an X-ray diffraction study. Complexes 1 and 2 belong to hexagonal space group P6(3) with unit cell parameters a = b = 11.843(3), c = 10.304(4) angstrom, V = 1251.7(9) angstrom-3, D(c) = 1.49 g.cm-3, Z = 2 for 1, and a = b = 11.805(2), c = 10.236(2) angstrom, V = 1235.4(6) angstrom-3 D(c) = 1.54 g.cm-3, Z = 2 for 2. The structures were solved by Patterson and Fourier techniques and refined by least-squares to final discrepancy indices of R = 0.049, R(w) = 0.053 using 925 independent reflections with I greater-than-or-equal-to 3-sigma(I) for 1, and R = 0.023, R(w) = 0.025 using 1327 independent reflections with I greater-than-or-equal-to 3-sigma(I) for 2. Coordination numbers for Nd3+ and Gd3+ are 10; the average bond lengths Nd-O and Gd-O are 2.557(21) and 2.459(13) angstrom, respectively. The structural studies showed the complexes to have 3-fold symmetry, but the THF molecule has no such symmetry; consequently the arrangement of carbon atoms in the THF molecule are disordered.

Synthesis and structure of (η5-C5H5)2Yb·DME

Abstract (η 5 -C 5 H 5 2 YbCl·THF reacts with an equivalent molecular quantity of K(2,4-C 7 H 11 ) (2,4-dimethyl pentadienyl potassium), and treatment of the product with DME yields (η 5 -C 5 H 5 ) 2 Yb·DME. The crystal of (η 5 -C 5 H 5 ) 2 Yb·DME belongs to the orthorhombic space group Fdd 2 with α = 13.678(4) A, b = 23.255(6) A, c = 9.192(2) A and Z = 8. The crystal parameters are found to differ from previously reported data.

PREPARATION AND CRYSTAL-STRUCTURE OF A NEW ION-PAIR COMPLEX WITH ANIONIC TETRAMETHYLETHYLENE-BRIDGED DICYCLOPENTADIENYL YTTERBIUM CHLORIDE

Abstract The ion-pair (Me 4 C 2 Cp 2 YbCl 2 ) − (Mg 2 Cl 3 ·6THF) + ·THF (Cp = cyclopentadienyl and THF = tetrahydrofuran) was prepared by the reaction of Me 4 C 2 Cp 2 Mg 2 Cl 2 ·4THF with anhydrous ytterbium chloride in THF. X-Ray diffraction intensities were collected with a four-circle diffractometer at −80°C. The compound crystallizes in the triclinic space group P 1 with a 16.911(5), b 13.268(5), c 13.772(4) A, α 116.52(2), β 111.30 (2), γ 87.61 (3)°, and D calc 1.45 g cm −3 for Z = 2. Final R value is 0.051 for 6566 independent observed reflections. The structure of the cation shows that the two magnesium atoms, each attached to three THF molecules, are bridged by three chlorines, thus forming two distorted octahedra joined along three common edges. In the anion, the ytterbium atom is coordinated in a pseudo-tetrahedral geometry by two chlorines and two Cp rings which are bridged by the tetramethylethylene. Both the bridged angles at the ethylene carbon atoms are greater than those in a normal tetrahedron, viz. 114.6(9)°, which indicates that the ligand is strained.

Synthesis and crystal structure of [Me4C2Cp2SmCl.THF]2

Abstract Me4C2(C5H4MgCl)2(THF) (THF = tetrahedrofuran) reacts with anhydrous SmCl3 in THF to give [Me4C2Cp2SmCl · THF]2. The molecule is a dimer. Sm1 and Sm2 are bridged unsymmetrically by two chlorine atoms [Sm(1)Cl(1) 2.787(2), Sm(1)Cl(2) 2.848(2), Sm(2)Cl(1) 2.823(2), Sm(2)Cl(2) 2.795(2) A]. Two centroids of cyclopentadienyls two chlorine atoms, and an oxyten of THF form of a distorted trigonal bipyramid around samarium. The effective coordination number of samarium is 9.

Synthesis and crystal structure of tetrahydrpfurfurylcyclopentadienyl sodium tetrahydrofuranate complex

Abstract A tetrahydrofurfurylcyclopentadienyl sodium tetrahydrofuranate complex was prepared by the reaction of tetrahydrofurfurylcyclopentadiene with metallic sodium in THF. Its crystal structure was determined by X-ray analysis. In the crystal, the tetrahydrofuranate complex C4H7OCH2C5H4Na·THF adopts a puckered chain structure with an ν5-(C4H7OCH2)C5H4 ring connected by a bridging Na(THF) unit. The oxygen in the ν5-(C4H7OCH2)C5H4 ring is coordinated to the sodium atom.

Synthesis of phenyl lanthanide dichloride complexes and crystal structure of C6H5GdCl2·4THF

Abstract Anhydrous lanthanide trichlorides react with phenyl lithium in THF(tetrahydrofuran) to give the complexes, C 6 H 5 LnCl 2 · n THF (Ln = Pr, Sm, Gd; n = 3, 4). The crystal structure of the C 6 H 5 GdCl 2 ·4THF was determined by X-ray diffraction, orthorhombic space group Ccm 2 1 , a 12.776(6), b 12.954(6), c 15.802(3) A, V 2615.4(1.8) A 3 , Z = 4. The final R is 0.0438, R w 0.0445, Gd 3+ coordination number 7. The length of the GdC bond is 2.416(24) A, the average GdCl bond length is 2.677(8) A, that of GdO is 2.508(4) A, and the CC distance in the phenyl group is 1.378(41) A.

Crystal structures of bis(cyclopentadienyldicarbonyliron)sodium tetrahydrofuran and (cyclopentadienyldicarbonyliron)sodium tetramethylethylenediamine complexes

Abstract The extremely air-sensitive intermediate product [C 5 H 5 Fe(CO) 2 ] 2 Na·4THF (I) and final product [C 5 H 5 Fe(CO) 2 ]Na·TMEDA (II) have been obtained by the reduction of [C 5 H 5 Fe(CO) 2 ] 2 by Na/Hg. Their crystal structures have been determined at low temperature. The crystals belong to the monoclinic space group P 2 1 / n with a 10.155(5), b 17.121(4), c 18.667(6) A, and β 97.61(3)° for I, and to the orthorhombic space group P 2 1 2 1 2 1 with a 6.001(4), b 10.644(6) and c 24.214(11) A for II, respectively. Complex I has a linear chain structure with dimer anion [C 5 H 5 Fe(CO) 2 ] 2 − and complex cation (Na·4THF) + connected alternately by NaO(CO) bonds. Complex II has a spiral chain structure in which Na + with a TMEDA molecule and (C 5 H 5 Fe) − are bridged by carbonyl groups. A possible reaction mechanism based on the crystal structure is proposed.

Preparation and crystal structure of 2,4-dimethylpentadienyl-potassium tetramethylethylenediamine complex

Abstract The compound, 2,4-dimethylpentadienylpotassium tetramethylenediamine, was obtained by reaction of 2,4-dimethylpentadiene with metallic potassium in tetrahydrofuran (THF) in the presence of tetramethylethylenediamine (TMEDA) at −78°C. Its crystal structure was determined by a low temperature X-ray diffraction study. The crystal is monoclinic with space group P21/n, a 11.322(4), b 9.242(3), c 15.956(5) A, β 106.73(3)°, and Z = 4. The final R value is 0.055 for 964 observed reflections. The 2,4-dimethylpentadienyl anion adopts the planar U conformation. The potassium cations, each with a chelating TMEDA molecule attached, are linked by bridging anions while the anions are connected to the bridging cations with the average bond distances KC(1,5), KC(2,4) an KC(3), of 3.123, 3.216 and 3.248 A, respectively, to form a puckered chain. The structure of the complex is compared with those of 2,4-dimethylpentadiene complexes of transition metals and the bonding within the complex is described.