The crystal and molecular structure of bis(pentamethylcyclopentadienyl)dichlorotitanium(IV)

The structure of bis(pentamethylcyclopentadienyl)dichlorotitanium(IV) has been investigated by single-crystal X-ray diffraction techniques. [η-C₅(CH₃)₅]₂TiCl₂ crystallizes in the orthorhombic space group P2₁2₁2₁ with cell dimensions a = 10.816(1), b = 8.132(1), c = 22.259(1) Å; Z = 4. Full matrix, least-squares refinement converged to a final R index of 0.032 based on 1429 reflections. The configuration about the titanium atom is a distorted tetrahedron comprised of the two chlorine atoms and the centroids of the two η-cyclopentadienyl rings. Several ring methyl groups are bent considerably out of the cyclopentadienyl plane and away from the titanium atom. These out-of-plane deviations are attributable to chlorine—methyl crowding and methyl—methyl contacts between the two rings.     

The crystal and molecular structures of bis (pentafluorophenyl)disulphide and bis(pentafluorophenyl)diselenide

The structures of (C₆F₅)₂S₂ and (C₆F₅)₂Se₂ have been determined by single crystal, X-ray diffraction techniques. The compounds are isostructural although the molecules are packed differently in the crystal in comparison with their phenyl analogues. Important bond lengths and angles are: SS, 2.059(4)Å; SeSe, 2.319(4)Å; SC, 1.770Å; SeC, 1.910(15)Å; SSC, 101.3(3)°; SeSeC, 98.8(1)°.     

Syntheses,crystal structures,and IR spectra of isonicotinamide-isonicotinamidium bis(isonicotinamide)-tetrakis(isothiocyanato)ferrate(III) and isonicotinamidium chloride

Reaction of iron(III) thiocyanate with isonicotinamide (inia) in ethanol leads to formation of a dark red, air stabile crystalline iron(III) compound of composition [iniaH·inia][Fe(inia)₂(NCS-N)₄]. Single-crystal X-ray diffraction analysis shows the triclinic P–1 space group with unit cell parameters: a?=?8.2440(4)?Å, b?=?9.5540(3)?Å, c?=?11.2590(5)?Å, α?=?93.945(4)°, β?=?95.554(4)°, γ?=?96.285(3)°, and Z?=?1. The iron compound contains [iniaH·inia]⁺ cations and [Fe(inia)₂(NCS-N)₄]^– anions, which are held together by ionic interactions and hydrogen bonding. The Fe(III) is octahedrally coordinated by six nitrogens, four from NCS^– in the equatorial plane and two from inia occupying axial positions. The [iniaH]Cl has been formed by reaction of inia with hydrochloric acid. [iniaH]Cl crystallized in the monoclinic C2/c space group with unit cell parameters: a?=?25.156(5)?Å, b?=?5.095(1)?Å, c?=?12.747(3)?Å, and Z?=?8. Both compounds have also been characterized by elemental analyses and infrared spectroscopy. Structural and infrared spectral data are compared with data of similar compounds in the literature.     

Complexes of mono- and bis(2-carboxyethyl)-2-picolylamine: Synthesis and crystal and molecular structures

N-(2-Pyridylmethyl)iminodipropionic (I) and N-(2-pyridylmethyl)-3-aminopropionic acids (II) were obtained. A reaction of acid I with a Cu(II) salt gave a 2: 2 complex (III); a reaction of acid II with a Ni(II) salt yielded a 1 : 2 complex (IV). The crystal structures of these complexes were determined by X-ray diffraction. The abilities of compounds I and II to form complexes were compared with the literature data for other ligands containing the N-(2-pyridylmethyl)amino fragment. The structural features of the chelate complexes with 2-aminomethylpyridine derivatives were revealed, depending on the other substituents and the metal center.     

The crystal and molecular structure of bis(triphenylsilicon) carbodiimide

The structure of (Ph₃SiN)₂C has been determined by single crystal X-ray diffraction. The structure was solved by direct methods and refined to R = 0.071 for 593 independent diffractometer data. The crystals are rhombohedral, R$\text{3}$ with a = b = c 18.201(20) Å, α = β = γ = 48.82(2)°, and Z = 4. The three crystallographically independent molecules each have linear SiNCNSi chains lying along the crystallographic threefold axes; in two of the molecules the central carbon atom lies on a centre of symmetry. Principal mean bond lengths and angles are: Si, 1.696(25); SiC, 1.846(20); NC, 1.164(30); CC, 1.387(14) Å; CSi, 108.2(6); and CSiC, 110.8(6)°.     

The crystal and molecular structure of bis(biscyclopentadienylchlorotitanium) oxide

Bis(biscyclopentadienylchlorotitanium) oxide, Cp₂TiCl)₂O, crystallizes in the enantiomorphic space groups P3₁21 and P3₂21 with a 7.742(1), c 27.177(7) Å. In this study only twins were obtained. On the basis of intensity data for 1106 independent reflections, the structure is described in P3₁21 with final residuals of R_F = 3.27% and R_WF = 2.53%. The molecule is very similar to that of the analogous zirconium compound. Mean bond lengths are CpTi(π), 2.09; ClTi, 2.41; and TiO, 1.84 Å. The TiOTi bond angle is 173.8°.     

The crystal and molecular structure of dioxo bis (2,2,6,6 - tetramethylheptane -3,5 dionato)methanol uranium (VI)

UO₂(thd)₂ CH₃OH (thd = tetramethylheptane-3,5-dione) is monoclinic, with a = 10.602(11), b = 22.883(20), c = 12.054(11) Å and β = 105.90(3)°, Z = 4 and space group P2₁/c. The structure, which is molecular, was solved by conventional Patterson and Fourier techniques with 3173 independent (hkl) reflexions collected with MoKα radiation (λ = 0.7107 Å), and refined to R = σ(|Fo|-|Fc|)/σ|Fo| = 0.093. The uranium coordination polyhedron is a pentagonal bipyramid, with UO (carbonyl) distances between 2.25 and 2.37 Å and a longer UO (methanol) distance of 2.50 Å. The uranyl group is linear (uranyl angle 179.3(8)°). The pentagon oxygen atoms and uranium do not form a planar system, as there are deviations of up to 0.17 Å from the mean plane. If the methanol oxygen atom O(7) is excluded from the plane calculation, the remaining atoms are more nearly planar. The four carbonyl oxygens are coplanar, with uranium 0.08 Å from their plane. The methanol oxygen is 0.28(4) Å from this second plane.The two (thd) molecules, excluding methyl carbons, are planar and are inclined at 43.6° to each other in a boat form and at 29.1 and 14.5° to the pentagonal plane. The methanol CO bond is inclined at 133° to the UO bond, confirming the ligand is the neutral CH₃OH molecule, and not CHO^?₃.     

X-ray diffraction study of the bonding between sulphur and the elements of group IVB. The crystal and molecular structures of methylthiotriphenyl-methane, -silicon, -germanium, -tin and -lead

The X-ray analyses of the compounds methylthiotriphenyl-methane, -silicon, -germanium, -tin, and -lead were undertaken to see if the electronic interactions which affect the X-S bond could influence the molecular geometries. The five structures were solved or by direct methods or by Patterson and Fourier techniques and refined anisotropically to R = 0.053, 0.036, 0.031, 0.041, and 0.070 respectively. The central atom exhibits a distorted tetrahedral coordination; only the propeller shape orientation of the phenyl rings seems to be determined by differences in the electronic nature of the central atoms as well as by steric effects.     

Novel seven coordination geometry of Sn(IV): crystal structures of phthalocyaninato bis(undecylcarboxylato)Sn(IV), its Si(IV) analogue, and phthalocyaninato bis(chloro)silicon(IV). The electrochemistry of the Si(IV) analogue and related compounds

Three newly elucidated crystal structures of group IV phthalocyaninato complexes are reported, along with data for two further SiPc carboxylate complexes. In one of these crystal structures, bis(undecylcarboxylate)Sn(IV) phthalocyanine, the tin ion is seven coordinate, which is a unique finding for this atom in phthalocyanine ring coordination. Comparison of these structures with other group IV phthalocyaninato and related structures reveals differences, illustrating features significant in the chemistries of Si(IV) and Sn(IV) ions. These differences are thought to originate from their differing sizes and polarizabilities. The structures show that the Sn(IV) ion can only occupy an in-plane location in the phthalocyaninato ring where it elongates toward the two axial ligands. When the axial ligands do not facilitate this elongation cis coordination is preferred and the Sn(IV) ion sits above the phthalocyaninato ring plane. In contrast, the Si(IV) structures, with smaller, harder (i.e., less polarizable) Si(IV) ions, are six coordinate with the Si(IV) ion in the phthalocyaninato ring plane in a distorted octahedral symmetry. The electronic spectra and cyclic voltammetry of some of the Si compounds indicate that on the electrode the oxidized/reduced species behave as though they are in a solid film, rather than a soluble freely diffusing species.     

The crystal and molecular structure of bis(thiourea)iron (11) thiocyanate

Summary The crystal structure of bis(thiourea)iron(II) thiocyanate, Fe[SC(NH₂)₂]₂(NCS)₂, has been determined and refined by three-dimensional x-ray analysis. The complex crystallizes in the triclinic system, space group P –1, witha = 10.114(6),b = 7.662(8),c = 3.897(10) Å, = 105.0(2)°, = 81.8(3)°, = 96.4(3)° andz = 1. It is isostructural with M(tu)₂(NCS)₂, where M = Mn, Co or Ni and to = thiourea. The iron atom is located on a centre of symmetry and is coordinated to four planar sulfur atoms of the thiourea ligands (Fe-S 2.61 and 2.65 Å) and two nitrogen atoms of the thiocyanate groups (Fe-N 2.05 Å) in a distorted octahedral way. These octahedra are linked in chains with each thionilic sulfur atom shared by two adjacent iron atoms; magnetic measurements, Mössbauer and spectroscopic data are consistent with this polymeric structure.     

The crystal and molecular structure of hexadecaphenyloctasiloxyspiro(9,9)titanate(IV)

The crystal and molecular structures of the title compound have been determined by single crystal X-ray diffraction methods. In the spiro molecule, the metal atom has a geometry very close to tetrahedral, with OTiO angles of 107.9–111.0(2)° and very short TiO bonds of length 1.777–1.791(5)Å. The two TiO₅Si₄ rings have different, ill-defined conformations; the SiO bond lengths and SiOSi angles are similar to those in (SiO)_n rings.