CRYSTAL AND MOLECULAR STRUCTURE OF BIS(TRIPHENYLBENZYLPHOSPHONIUM) TETRABROMOCADMATE

Abstract

The molecular and crystal structure of bis(triphenylbenzylphosphonium)tetrabromocadmate has been determined by x-ray diffractometer data. Crystals are triclinic, space-group Pl with two formula units in a unit-cell of dimensions a = 12.506(6), b = 10.471(5), c = 18.396(13) Å, α = 93.07(4)°, β = 105.75(5)°, γ = 92.58(4)°. The structure was solved by direct and Fourier methods and refined by least-squares techniques to R = 0.061 for 3723 independent observed reflections. The structure consists of tetrabromocadmate (II) anions and triphenylbenzylphosphonium cations, both with a quasi-perfect tetrahedral symmetry around the cadmium and phosphorus atoms. The most significant average bond distances are: Cd-Br, 2.588(2) Å, P[sbnd]C (Phen), 1.794(5) Å and P[sbnd]CH₂, 1.806(6) Å. The P[sbnd]C (Phen) bonds are in slightly distorted staggered conformation (gauche-, gauche +, and trans) in respect of the C (Phen)-CH₂ bonds of the benzyl residues. The interatomic distances between the ions correspond to the usual Van der Waals distances.     

CRYSTAL AND MOLECULAR STRUCTURE OF BIS(2-ME-THOXYETHYL-CYCLOPENTADIENYL) ERBIUM CHLORIDE

<正> Complex Cp'2 ErCl(Cp'=2-methoxyethylcyelopentadienyl)(I)has been synthesized by the reaction of Cp' Na and ErCl3 in THF It crystallizes in space group Pnma with a=12.269(0),b=11.742(6),c=11.197(2)A,V=1613.1A3,Dc=1.849 g/cm3,Z=4,A=0.71073 A,μ(MoKa)=54.38 cm-1,F(000)=876,R=0.043,Rw=0.046.The Er atom is formally nine-coordinated with a pseudo-trigonal bipyramidal geometry with the "equatorial" plane composed of the Er atom,the Cl atom and the centers(1)and(2)of the two Cp rings(Cp=cy-clopentadienyl).The molecule is located at the crystallographic mirror plane through the atom C(3),C(4),C(S),Er,O(1)and C(6).The atom Cl and the atoms of Cp'(2)(except C(16)and C(16'))are disordered with an occupancy of 0.5 each.     

THE CRYSTAL AND MOLECULAR STRUCTURE OF BIS(p-NITROPHENACETURO)DIAQUOCOPPER(II)

Abstract

The crystal and molecular structure of [Cu(p-NO₂C₆ H₅CH₂CONHCH₂CO₂)₂ (H₂O)₂] has been determined by single-crystal, x-ray diffraction techniques. The compound is centrosymmetric crystallizing in a monoclinic unit cell (P2₁/c) with two molecules per unit cell. The cell dimensions are: a = 11.588(1)A, b = 11.405(1)A, c = 8.041(1)Å and β = 93.47 · (1). The structure was solved by Patterson methods and refined to a value of R = 0.063. The coordination about the copper assumes an unexpected square planar geometry in which two phenaceturic moieties are each coordinated through the carboxylic oxygen (Cu—O = 1.933A) and the two waters complete the coordination (Cu—O_w = 1.959Å). The overall conformation of the phenaceturic acid is retained although there is a rotation of 180° about the peptide C—N bond.     

CRYSTAL AND MOLECULAR STRUCTURE OF BIS(O,O'-DICYCLOHEXYLDITHIOPHOSPHATO)-NICKEL(Ⅱ)

<正> Ni[(C6H11O)2PS2]2, Mr=627.39, Monoclinic, P21/n, a=11.802(7), b= 9.336(2), c=14.177(5) A,B=96.72(4)°,V=1551.3A3, Z=2, Dc=1.343g·cm-3, MoKα radiation λ=0.71073A, F(000)=648e, R=0.068 for 2642 reflections. Ni(Ⅱ) atom is surrounded by four sulfur atoms, forming a square.     

PREPARATION, PROPERTIES, AND MOLECULAR STRUCTURE OF trans-DICYANO BIS[BIS(DIPHENYLPHOSPHINO) METHANE]PALLADIUM (Ⅱ)

<正> The crystal structure of the title compound has been determined. PdC52H44N2P4, Mr = 927. 2, monoclinic, space group P21 /n, a =12. 102(2), b = 9.997(2), c=20. 254(5)(?),β=93. 80(2)°, V = 2445. 0(?)3, Z = 2, R =0. 075 and Rw = 0. 095 for 3535 observed reflections (I>3σ(I)), The palladium atom is located on the symmetric center and adopts a square planar coordination surroundings with two biphosphine ligands and two cyanide groups. The molecular structure in crystals is different from that in solution in which the molecule is very fluxional, probably due to the rapid alteration in coordination sites between the coordinated and uncoordinated phosphorus atoms of the biphosphine ligands. Their properties are also reported.     

THE CRYSTAL AND MOLECULAR STRUCTURE OF RUBIDIUM BIS(PYRIDINE-2,6-DICARBOXYLATO)-CHROMATE(III)

Abstract

A three dimensional X-ray structural analysis of rubidium bis (pyridine-2,6-dicarboxylato)chromate(III), Rb[Cr(dipic)₂], has been carried out. The structure was refined by full matrix least-squares methods, using 713 observed independent reflections recorded at room temperature, to a conventional weighted R of 0.034. The crystals are tetragonal with a=b=6.950(3) Å, c=29.47(1) Å, space group 14 1/a and Z=4. The point group symmetry of the [Cr(dipic)₂]^? ion is S₄. The Cr–N and Cr–O distances (1.974(4) and 2.000(3) Å respectively) noticeably differ from the usual values in aminoacid chromium(III) complexes. The π bonding effect of the pyridine nitrogen atom corroborates the previous spectral studies on the sodium salt of this complex. The lability of [Cr(dipic)₂]^? in acid solution has been tentatively explained on the basis of the relatively severe strain within the complex ion.     

CRYSTAL AND MOLECULAR STRUCTURE OF 2-PHBNYLQUINOXALINE

<正> C14H10N2,Mr =206.24, space group P21/n, a =5.861(3), b =10.230 (5), c =17.440(11) A,β=92.07(5)°,V= 1045(1) A3,Z=4, Dx=1.31 g.cm-3, MoKa radiation,u=0.73 cm-1,F(000)=432,R=0.063 for 1054 observed reflections. 2-Phenylquinoxaline molecule is approximately planar. The dihedral angle between the quinoxaline ring and the substituted phenyl ring is 7.0°. The C-C bond distance connecting these two rings is 1.495(4) A. The whole molecule is a conjugation system.     

CRYSTAL AND MOLECULAR STRUCTURE OF DIPOTASSIUM TRIS(HYDROXYACETATO)VANADYL (IV) MONOHYDRATE

<正> Preliminary information. The vanadyl complexes are found to be increasingly used in the areas of catalysis, new materials research as well as in bio chemistry. Therefore, more attentions have been paid to such compounds. The title complex K_2[VO(C_2H_3O-3)_2(C_2H_2O_3)] H_2O has been prepared by reaction of VOSO_4 with hydroxyacetic acid in aqueous solution, with KOH added to a suitable PH value.     

CRYSTAL STRUCTURE OF (μ-OXO)-BIS[BIS(DIETHYLDITHIOCARBAMATO)- OXO-MOLYBDENUM]

<正> INTRODUCTION. The reaction oF MoCl_3·3H_2O with dithiocarbamate in organic solvents is a interesting research area. Thus, several dinuclear and trinuclear molybdenum complexes have been synthesized The dinuclear oxo-dridged molybdenum compound was obtained by this reaction in acetonmethanol mixed solvent. The molecular configuration has been characterized     

THE MOLECULAR AND CRYSTAL STRUCTURE OF [Et4N]2[Fe2S2（NO）4]

<正> The compound [Et_4N]_2[Fe_2S_2(NO)_4] (M_r=556.36) crystallizes in the monoclinic,space group P 2_1/n with a=9. 688(3), b=10. 882(2), c=12. 625(2), β=97. 86(3)°, Z=2, V=1318. 4, D_c=1. 40g/cm~3, ;μ(MoK_a)=12. 8cm~(-1) and F(000)=588. The final R=0. 028 and R_w=0. 029 for 2041 reflections (I≥3σ(I)).The crystals of [Et_4N]_2[Fe_2S_2(NO)_4] consist of discrete cations [Et_4N]~+ and anions     

CRYSTAL AND MOLECULAR STRUCTURE OF RABDOSERRIN-B

<正> INTRODUCTION. Four compounds of diterpenoids that have in vitro cytotoxity against cultured Hala cells have been obtained by means of extraction from Rabdosia serra(Maxim) Hara, a chinese medical herb. They are Rabdoserrin A (Rab A), Rabdoserrin B (Rab B), Excisanin A and Kamebakaurin (Kam). Among them, Rab A and Rab B are new compounds. Crystal structures of Rab A and Kam have been solved. The chemical structure of Rab B has been     

CRYSTAL AND MOLECULAR STRUCTURE OF TETRAPHENYLDIARSINE

<正> The title compound, C24H20As2(Mr=458.24), crystallizes in mono-clinic with space group P21/n and a=6.268(2), b=7.494(2), c=21.340(7)A, β= 91.027(3)°, V=1002.6 A3, Z=2, D.x=1.518gcm-3. The final value of R is 0.059 for 1619 observed reflections. The four phenyls arrange in a staggered trans-conformation around the As-As' bond.     

CRYSTAL AND MOLECULAR STRUCTURE OF (CYANOETHYLOXY-FERROCENYL)-p-FLUOROPHENYL METHANE

<正> The crystal structure of (Cyanoethyloxy-ferrocenyl)-p-fluoro-phenyl methane (Fc-C(H)OCH2CH2CN, Mr=363.23) belongs to the monoclinic spacegroup P21/c with unit cell parameters: a =9.751(3), b =18.448(4), c =9.891(4)A,β= 105.71(3)°,V= 1712.7A3,Z=4,Dc=1.409g/cm3,μ=8.930cm-1,λ=0.71073A (MoKα),R=0.05. The structure and reactivities of the title compound are compared with those of its isomer.     

CRYSTAL AND MOLECULAR STRUCTURE OF STEMOTININE

<正> C18H25NO5, Mr = 335.40, tetragonal, P41212, a = 15.578(4), c =14.723(3) A, V =3573(2) A3, Z = 8, D = 1.247 g cm-3, MoKα,λ= 0.71069 A, μ = 0.;85 cm-1, T = 293K, final R .= 0.100 and RW (on F2) = 0.080 for 1095 observed data [|FO| > 2σ(|FO|)]. The structure confirms the spectrbscopic assignment of a pentacyclic skeleton containing two α-methyl-γ-lactone rings, one ether and one tertiary amine.     

CRYSTAL AND MOLECULAR STRUCTURE OF RABDOSERRIN-D

<正> Introduction. Rabdoserrin-D C_(20)H_(30)O_5 is extracted from Rabdosia serra (Maxim) Hara, a Chinese medical herb with antitumourous activities. Tests show that this compound has a high inhibitory effect on the Hela cell cultured outside the body and thus it is worth further studying, The investigation on the     

SYNTHESIS AND CRYSTAL STRUCTURE OF BIS (TETRAETHYLAMMONIUM) BIS[μ-(l,2-DITHIOETHELENE)-S,S']-BIS[l,2-DITHIOETHELENE-S,S']-DI-IRON(Ⅲ)

<正> INTRODUCTION. In our attempts of chemical simulation of the active center of nitrogenase we have been interested in the reaction system of various ferrous thiolates with thiomolybdatee. In previous papers, we have reported the syntheses of ferrous monodentothiolates and their reactions with tetrathiomolybdate. The possible structure type of ferrous thiolates when bidentothiols are used inspired our interest in this work.     

CRYSTAL AND MOLECULAR STRUCTURE OF THE ADDUCT OF BIS [4,4,4-TRIFLUOR-1-(2-THIENYL) Butandion-1,3] COPPER (Ⅱ) WITH DIMETHYLFORMAMIDE, [Cu(TTA)_2(DMF)]

<正> [Cu(C8H4F3O2S)2(C3H7NO)], Mr = 579. 0, monoclinic, P21/c, a = 9. 4851(6), b = 26. 6574(6), c=9.2619(6) A ,β=96.08(3)°, V = 2328.7A3, Z=4, Dc=1. 65gcm-3, μ(MoKa) = 7. 2cm-1, F (000) = 1172, MoKa radiation, final R = 0. 074 and Rw = 0. 068 for 1841 reflections with I≥3σ(Ⅰ). The Cu(Ⅱ) atom is coordinated by five oxygen atoms, one of which from DMF is in the axial position, to form a square pyramidal geometry. That the thenoyl groups in the ligands take the cis-form around the Cu(Ⅱ) atom is explained by the hydrogen bonding effect.     

SYNTHESIS AND X-RAY CRYSTAL STRUCTURE OF BIS (2-AMINOMETHYLAZIRIDINE)NICKEL(II) PERCHLORATE

Abstract

The structure of the big (2-aminomethylaziridine = azida)nickel(II) complex was determined by X-ray diffraction methods. The compound, [Ni(azida)₂](C1O₄)2, crystallizes in the triclinic space group P1, Z=l, with a = 7.3545(4), b = 8.5235(5), c = 6.2156(4)Å, α= 101.871(6). β = 103.217(6), γ= 111.283(4)°, and V= 335.07(5) ų. The crystal shows discrete centrosymmetncal [Ni(azida)]²⁺ units in which azida acts as bidentate chelating ligand through N aziridine and N amino atoms. Thus, Ni has a four-coordinate square-planar geometry with four nitrogens of azida. The aziridine ring is almost perpendicular to the coordination plane. The dihedral angle between the aziridine plane and the coordination plane is 75.28°.     

MOLECULAR STRUCTURE OF (BENZOPHENONE)BIS(TRICARBONYLCHROMIUM)

<正> The title crystal belongs to monoclinic system, space group P21/c, with 3=14.794(2), b=7.360(1), c=16.029(2) A, β=94.95(2)0, Z=4, V=1738.9(6)A3, Dx=1.735 g/cm3. The final R=0.047, Rw=0.052.