Crystal structure,vibrational studies,optical properties,and Hirshfeld surface analysis of (C5H6N5)2[Cr2O7]

Single crystals of a new organic–inorganic compound, (C₅H₆N₅)₂Cr₂O₇ (1), adeninium dichromate, were grown by the slow evaporation technique and characterized by X-ray diffraction, infrared absorption, and the optical properties were also investigated by UV-vis absorption spectroscopy. The compound crystallizes in the triclinic system and P-1 space group with a = 11.6850(2) Å, b = 11.7531(5) Å, c = 14.5603(7) Å, α = 83.956(3)°, β = 70.481(4)°, γ = 61.863(2)°, V = 1658.70(12) Å³. The structure of the compound consists of four adeninium, (C₅H₅N₂)⁺, cations, and two dichromate dianions with all the atoms situated in general positions. Each dichromate anion is formed by two tetrahedral CrO₄ joined through shared O atoms and are linked to the cations with several weak hydrogen bonding interactions resulting in an extended network. 3-D Hirshfeld surface analysis and 2-D fingerprint plots indicate that the packing is dominated by H?O/O?H and H?N/N?H contacts.     

Synthesis and structure analysis of (K[DB18 C6])4(C60)5·12THF containing C60 in three different bonding states

A new fulleride, (K[DB18C6])₄(C₆₀)₅?12 THF, was prepared in solution using the “break‐and‐seal” approach by reacting potassium, fullerene, and dibenzo[18]crown‐6 in tetrahydrofuran. Single crystals were grown from solution by the modified “temperature difference method”. X‐ray analysis was performed revealing a reversible phase transition occurring on cooling. Three different crystal structures of the title compound at different temperatures of data acquisition are addressed in detail: the “high‐temperature phase” at 225 K (C2, Z=2, a=49.055(1), b=15.075(3), c=18.312(4) Å, β=97.89(3)°), the “transitional phase” at 175 K (C2 m, Z=2, a=48.436(5), b=15.128(1), c=18.280(2) Å, β=97.90(1)°), and the “low‐temperature phase” at 125 K (Cc, Z=4, a=56.239(1), b=15.112(3), c=36.425(7) Å, β=121.99(1)°). On cooling, partial radical recombination of C₆₀^.? into the (C₆₀)₂^2? dimeric dianion occurs; this is first time that the fully ordered dimer has been observed. Further cooling leads to formation of a superstructure with doubled cell volume in a different space group. Below 125 K, C₆₀ exists in the structure in three different bonding states: in the form of C₆₀^.? radical ions, (C₆₀)₂^2? dianions, and neutral C₆₀, this being without precedent in the fullerene chemistry, as well. Experimental observations of one conformation exclusively of the fullerene dimer in the crystal structure are further explained on the basis of DFT calculations considering charge distribution patterns. Temperature‐dependent measurements of magnetic susceptibility at different magnetic fields confirm the phase transition occurring at about 220 K as observed crystallographically, and enable for unambiguous charge assignment to the different C₆₀ species in the title fulleride.     

Seltenerdhalogenide Ln4X5Z. Teil 1: C und/oder C2 in Ln4X5Z

Rare Earth Halides Ln₄X₅Z. Part 1: C and/or C₂ in Ln₄X₅Z The compounds Ln₄X₅C_n (Ln = La, Ce, Pr; X = Br, I and 1.0 < n < 2.0) are prepared by the reaction of LnX₃, Ln metal and graphite in sealed Ta‐ampoules at temperatures 850 °C < T < 1050 °C. They crystallize in the monoclinic space group C2/m. La₄I₅C_1.5: a = 19.849(4) Å, b = 4.1410(8) Å, c = 8.956(2) Å, β = 103.86(3)°, La₄I₅C_2.0: a = 19.907(4) Å, b = 4.1482(8) Å, c = 8.963(2) Å, β = 104.36(3)°, Ce₄Br₅C_1.0: a = 18.306(5) Å, b = 3.9735(6) Å, c = 8.378(2) Å, β=104.91(2)°, Ce₄Br₅C_1.5: a = 18.996(2) Å, b = 3.9310(3) Å, c = 8.282(7) Å, β = 106.74(1)°, Pr₄Br₅C_1.3: a = 18.467(2) Å, b = 3.911(1) Å, c = 8.258(7) Å, β = 105.25(1)° and Pr₄Br₅C_1.5: a = 19.044(2) Å, b = 3.9368(1) Å, c = 8.254(7) Å, β = 106.48(1)°. In the crystal structure the lanthanide metals are connected to Ln₆‐octahedra centered by carbon atoms or C₂‐groups. The Ln₆‐octahedra are condensed via opposite edges to chains and surrounded by X atoms which interconnect the chains. A part n of isolated C‐atoms is substituted by 1‐n C₂‐groups. The C‐C distances range between 1.26 and 1.40Å. In the ionic formulation (Ln³⁺)₄(X^?)₅(C^4?)_n(C₂^m?)_1?n·e^? with 0 < n < 1 and m = 2, 4, 6 (C₂^2?, C₂^4? C₂^6?), there are 1 < e^? < 5 electrons centered in metal‐metal bonds.     

STRUCTURE and CONFORMATION OF PHOTOSYNTHETIC PIGMENTS and RELATED COMPOUNDS. 2. NICKEL (II) METHYL PYROPHEOPHORBIDE a–A SEVERELY ISTORTED CHLOROPHYLL DERIVATIVE*

The crystal structure of Ni(II) methyl pryopheophorbide a (3) (C_MH₃₄N₄Ni0₃, M_u= 605.4) was determined by x-ray diffraction methods in order to determine the influence of the nickel-ion on the ring conformation. The crystals were blue octahedrons and crystallized in the tetragonal space group P4₁2₁,2 with a= 14.727(4) Å, c = 26.666(12) Å, V= 5781(3) ųZ= 8, D= 1.391 mg/m³. (Mo Kα) = 0.71069 Åμ= 0.713 mm^?1, F(000) = 2544, 130 K. The final R value was 0.064 for 4096 observed reflections, wR = 0.065. The molecule is severely distorted and shows a saddle-shaped ring conformation, the β-pyrrole atoms being displaced up to 0.6 A out of the plane of the nitrogens. The severe deformation restricts the use of Ni-derivatives in spectroscopic model studies on chlorophylls and provides an example for the conformational flexibility of the phorbin macrocycle.     

Earth Alkaline Tetrathiosquarates: Syntheses and Crystal Structures of MgC4S4 · 6 H2O and CaC4S4 · 4 H2O

Concentrated aqueous solutions of magnesium chloride and calcium nitrate, respectively, allow on addition of the potassium salt of tetrathiosquarate, K₂C₄S₄ · H₂O, the isolation of the earth alkaline salts MgC₄S₄ · 6 H₂O ( 1 ) and CaC₄S₄ · 4 H₂O ( 2 ) as orange and red crystals. The crystal structure determinations ( 1 : monoclinic, C2/c, a = 17.2280(7), b = 5.9185(2), c = 13.1480(4) Å, β = 104.730(3)°, Z = 4; 2 : monoclinic, P2₁/m, a = 7.8515(3), b = 12.7705(5), c = 10.6010(4) Å, β = 93.228(2)°, Z = 4) show the presence of C₄S₄^2? ions with almost undistorted D_4h symmetry having average C–C and C–S bond lengths of 1.451Å and 1.659Å for 1 and 1.451Å and 1.655Å for 2 . The structure of 1 contains discrete, octahedral [Mg(H₂O)₆]²⁺ complexes. Several O–H····O and O–H····S bridges with H····O and H····S distances of less than 2.50Å connect cations and anions. The structure of 2 is built of concatenated, edge‐sharing Ca(H₂O)₆S₂ polyhedra. The Ca²⁺ ions have the coordination number eight, C₄S₄^2? act as a chelating ligands towards Ca²⁺ with Ca–S distances of 3.14Å. The infrared and Raman spectra show bands typical for the molecular building units of the two compounds.     

Synthesis,Crystal Structure,Spectral and Thermodynamic Properties of One Benzoindole Pentamethine Cyanine Dye

One benzoindole pentamethine cyanine dye was synthesized and characterized by ¹H NMR, IR, MS and UV‐Vis spectra. The UV‐Vis absorption and fluorescence spectra of the dye in chloroform, dimethyl sulfoxide, acetone, ethanol and methanol were investigated, and the λ_max of the dye was in the region 682.0–689.0 nm with large molar extinction coefficients (? > 10⁵ M^?1cm^?1) in different solvents. The structure of the dye was also characterized and analyzed by X‐ray diffraction. Crystallographic data revealed that the dye belonged to orthorhombic, with space group P2₁2₁2₁, a = 10.059(2) Å, b = 15.098(4) Å, c = 24.989(6) Å, V = 3794.8(15) ų, Z = 4. The C‐H···F intermolecular hydrogen bonds were displayed in the molecular system, which were effective in the molecular packing. The aggregation behavior and thermodynamic properties of the dye in aqueous methanol solution were also studied by means of UV‐Vis spectroscopy methods. The results indicated that the dye existed monomer‐dimer equilibrium in aqueous methanol solutions. The fundamental properties of the dye, such as the dimeric association constant K_D, the dimeric free energy ΔG_D, the dimeric entropy ΔS_D, and the dimeric enthalpy ΔH_D were determined. The ΔH_D of the dye was –46.0 kJ mol^?1.     

Li17Sb13S28: A New Lithium Ion Conductor and addition to the Phase Diagram Li2S–Sb2S3

Li₁₇Sb₁₃S₂₈ was synthesized by solid‐state reaction of stoichiometric amounts of anhydrous Li₂S and Sb₂S₃. The crystal structure of Li₁₇Sb₁₃S₂₈ was determined from dark‐red single crystals at room temperature. The title compound crystallizes in the monoclinic space group C2/m (no. 12) with a=12.765(2) Å, b=11.6195(8) Å, c=9.2564(9) Å, β=119.665(6)°, V=1193.0(2) ų, and Z=4 (data at 20 °C, lattice constants from powder diffraction). The crystal structure contains one cation site with a mixed occupation by Li and Sb, and one with an antimony split position. Antimony and sulfur form slightly distorted tetragonal bipyramidal [SbS₅E] units (E=free electron pair). Six of these units are arranged around a vacancy in the anion substructure. The lone electron pairs E of the antimony(III) cations are arranged around these vacancies. Thus, a variant of the rock salt structure type with ordered vacancies in the anionic substructure results. Impedance spectroscopic measurements of Li₁₇Sb₁₃S₂₈ show a specific conductivity of 2.9×10^?9 Ω^?1 cm^?1 at 323 K and of 7.9×10^?6 Ω^?1 cm^?1 at 563 K, the corresponding activation energy is E_A=0.4 eV below 403 K and E_A=0.6 eV above. Raman spectra are dominated by the Sb?S stretching modes of the [SbS₅] units at 315 and 341 cm^?1 at room temperature. Differential thermal analysis (DTA) measurements of Li₁₇Sb₁₃S₂₈ indicate peritectic melting at 854 K.     

Synthesis,Crystal Structures,and Optical/Electronic Properties of Sphere–Rod Shape Amphiphiles Based on a [60]Fullerene?Oligofluorene Conjugate

A series of sphere–rod shape amphiphiles, in which a [60]fullerene (C₆₀) sphere was connected to the center of an oligofluorene (OF) rod through a rigid linkage (OF‐C₆₀), were designed and synthesized. Alkyl chains of various lengths were attached onto the OFs on both sides of the C₆₀ spheres. These compounds, denoted as alkyl‐OF‐C₆₀, were fully characterized by ¹H NMR, ¹³C NMR, and FTIR spectroscopy and by MALDI‐TOF mass spectrometry. The morphologies and structures of their crystals were elucidated by wide‐angle X‐ray diffraction (WAXD) and by electron diffraction in transmission electron microscopy (TEM). Butyl‐OF‐C₆₀ forms a monoclinic unit cell (a=1.86, b=3.96, c=2.24 nm; α=γ=90°, β=68°; space group P2), octyl‐OF‐C₆₀ also forms a monoclinic unit cell (a=2.21, b=4.06, c=1.81 nm; α=γ=90°, β=75.5°; space group C2m), and dodecanyl‐OF‐C₆₀ forms a triclinic structure (a=1.82, b=4.35, c=2.26 nm; α=93.1°, β=94.5°, γ=92.7°; space group P1). The inequivalent spheres and rods were found to pack into an alternating layered structure of C₆₀ and OF in the crystals, thus resembling a “double‐cable” structure. UV/Vis absorption spectroscopy revealed an electron perturbation between the two individual chromophores (C₆₀ and OF) in their ground states. Fluorescence spectroscopy exhibited complete fluorescence quenching of their solutions in toluene, thus suggesting an effective energy transfer from OF to C₆₀. Cyclic voltammetry indicated that the energy‐level profiles of C₆₀ and OF remained essentially unchanged. This work has broad implications in terms of understanding the self‐assembly and molecular packing of conjugated materials in crystals and has potential applications in organic field‐effect transistors and bulk heterojunction solar cells.     

Difluorotetrakis(2‐oxypyridine)dirhenium(III) – Preparation,Crystallographic Structure,and Electrochemical Properties

The solid‐state‐melt reaction of (NH₄)₂[Re₂F₈] · 2H₂O with 2‐hydroxypyridine (2‐HOpy) produced dark‐red Re₂(2‐Opy)₄F₂ ( 1 ). This air‐stable compound was obtained in crystalline form as 1· CHCl₃. It was characterized in the solid state by single‐crystal X‐ray diffraction and in solution by UV/Vis spectroscopy and cyclic voltammetry. 1· CHCl₃ forms triclinic crystals with α = 8.3254(5) Å, b = 8.5563(5) Å, c = 11.6784(8) Å, α = 82.723(3)°, β = 75.769(3) °, γ = 64.407(2) °. The Re–Re and Re–F distances were 2.2091(7) and 2.115(6) Å, respectively. The molecule is isostructural with the corresponding chloro derivative.     

Das Lanthaniodidethanid o‐La5I9(C2) – Die orthorhombische Hochtemperaturmodifikation

The Lanthanumiodideethanide o‐La₅I₉(C₂) – The Orthorhombic High Temperature Modification o‐La₅I₉(C₂) is synthesized by reaction of LaI₃, La metal and graphite powder in sealed Ta containers at 850 °C < T < 900 °C. It crystallizes in the orthorhombic space group Pbca with a = 8.0247(16) Å, b = 16.887(3) Å, c = 35.886(7) Å. o‐Ce₅I₉(C₂) is isotypic with the lattice parameters a = 7.9284(4) Å, b = 16.714(1) Å, c = 35.530(3) Å. o‐La₅I₉(C₂) transforms at 800 °C to the triclinic low temperature modification t‐La₅I₉(C₂). The transformation is reversible. The La atoms form trigonal bipyramids centered by C₂ groups. These units are connected by iodine atoms above the faces (f), edges (e) and corners according to La₅(C₂)I(f)ⁱI(e)^i?i_2/2I(e)^i?a_7/2I(e)^a?i_7/2. The C‐C distance in the C₂ unit is 1.45(2) Å. The crystals with greenish luster are moisture sensitive.     

Preparation of a series of NiL(η2-C60) complexes (L = 1,2-bis(diphenylphosphino)ethane,and 1,1′-bis(diphenylphosphino)ferrocene) by zinc dust reduction

A simple method for preparation of nickel-fullerene coordination complexes has been developed. NiLCl₂(Br₂) and C₆₀ mixtures are reduced by zinc dust upon heating in o-dichlorobenzene. Diffusion of hexane into the reaction mixture results in formation of crystals of NiL(η²-C₆₀)?solvent (L = 1,2-bis(diphenylphosphino)ethane (dppe, 1), 1,3-bis(diphenylphosphino)propane (dppp, 2) and 1,1′-bis(diphenylphosphino)ferrocene (dppf, 3)). Nickel coordinates to the 6–6 bonds of C₆₀ by η²- type and has distorted square-planar geometry. The average Ni–C(C₆₀) bond lengths are 1.936(6)–1.977(3)?Å. We found that increase in the P(L)–Ni–P(L) angle and the dihedral angle between the PNiP and CNiC planes results in elongation of the Ni–C(C₆₀) and Ni–P(L) bonds by 0.04–0.06?Å. Complexes 1–3 contain zero-valent nickel since fullerenes are neutral according to the IR- and visible-NIR spectra. Some of the IR-active bands of C₆₀ are split into three bands in spectra of 1–3 due to C₆₀ symmetry lowering, and the F_1u(4) C₆₀ mode is shifted to lower wave numbers due to the π-back donation. The formation of 1–3 is accompanied by appearance of new bands in the visible range at 435–447 and 661–680 nm.     

Intermolecular interactions in the chiral and racemic forms of 3‐­hydroxy‐2‐(1‐oxoisoindolin‐2‐yl)­butanoic acid derived from threonine

The title compounds, C₁₂H₁₃NO₄, are derived from l ‐threonine and dl ‐threonine, respectively. Hydro­gen bonding in the chiral derivative, (2S/3R)‐3‐hydroxy‐2‐(1‐oxoisoindolin‐2‐yl)­butanoic acid, consists of O—H_acid?O_alkyl—H?O=C_indole chains [O?O 2.659 (3) and 2.718 (3) Å], Csp³—H?O and three C—H?π_arene interactions. In the (2R,3S/2S,3R) racemate, conventional carboxylic acid hydrogen bonding as cyclical (O—H?O=C)₂ [graph set R₂²(8)] is present, with O_alkyl—H?O=C_indole, Csp³—H?O and C—H?π_arene interactions. The COOH group geometry differs between the two forms, with C—O, C=O, C—C—O and C—C=O bond lengths and angles of 1.322 (3) and 1.193 (3) Å, and 109.7 (2) and 125.4 (3)°, respectively, in the chiral structure, and 1.2961 (17) and 1.2210 (18) Å, and 113.29 (12) and 122.63 (13)°, respectively, in the racemate structure. The O—C=O angles of 124.9 (3) and 124.05 (14)° are similar. The differences arise from the contrasting COOH hydrogen‐bonding environments in the two structures.     

Structural Relationships between the Hemiporphyrazine Macrocyclic Ligand and its Metal Complexes. I.: Saddle Shaped Neutral Ligand Hydrate,C26H16N8·-H2O,and Nickel Complex, [Ni(C26H14N8)]

Crystal and molecular structures of the neutral ligand hydrate, C₂₄H₁₆N₈·H₂O, and the diamagnetic nickel(II) complex, [Ni(C C₂₄H₁₆N₈)], have been determined by three-dimensional X-ray crystallography. Pertinent data are: C₂₄H₁₆N₈·H₂O, Pnmm with Z=2, a=4.6142(3), b=14.7687(7), c=15.0650(5) Å, R=0.068, R_w = 0.038; [Ni(C₂₄H₁₆N₈), 12/c with Z=4, a=22.0137(11), b=3.7637(4), c=23.4742(11) Å, β=92.7(1)°, R = 0.039, R_w=0.025. The overall conformations of the neutral ligand and the Ni(II) complex are similar, both have a pronounced saddle shape. The Ni(II) -N bond distances in the Ni-complex are 1.861(2) and 1.998(2) Å. The distances from nitrogen atoms to the center of the ring in free ligand are 2.020(3) and 2.220(3)Å, which arc significantly longer than those of Ni(II) complex A detailed comparison about the core size with similar ligand is presented.     

SYNTHESES,CHARACTERIZATION AND CRYSTAL STRUCTURE OF TETRAMETHYLDIBENZOTETRAAZA[14]-ANNULENE ZINC(II) COMPLEXES CONTAINING AN AXIAL BASE

Abstract

The complexes of Zn(tmtaa) and Zn(tmtaa)L [H₂tmtaa = tetramethyldibenzotetraaza[14]-annulene; L = triethylamine, pyridine (Py) and p-dimethylaminopyridine (p-N(CH₃)₂Py)] were synthesized and characterized by IR, LTV, mass and NMR spectra as well as DSC measurements. The effects of different axial ligands (L) on the spectral properties of the complexes have been studied. The crystal structure of Zn(tmtaa)N(C₂H₅)3 was determined by X-ray diffraction. The crystal belongs to a monoclinic system and the space group is P2₁/n. The cell parameters are a = 11.134(2)A, b = 17.453(4)Å, c= 13.784(3)Å, ? = 106.19(3)°, Z = 4, R₁, =0.0336 and wR₂= 0.0805 for 4539 independent reflections with I <2σ(I). The zinc(II) is coordinated through four nitrogen atoms of tmtaa and a nitrogen of triethylamine to form a five-coordinate square-pyramidal structure. The average bond length of Zn for the four nitrogens of tmtaa is 2.050(2)Å and for a nitrogen of triethylamine is 2.188(2)Å. The displacement of the zinc to the plane of four nitrogens of tmtaa is 0.563(2)Å.     

Tri-nuclear phthalocyanine complexes carrying N/O donor ligands as hydrogen peroxide catalysts,and their bleaching activity measurements by an online spectrophotometric method

A phthalocyanine (4) with four salicylhydrazone ligating groups that are directly linked through oxygen bridges to the macrocyclic core has been synthesized by condensation of tetrakis(4-formylphenoxy)phthalocyaninato zinc(II) (3) with salicylhydrazine. Salicylhydrazine was crystallized in methanol during the synthetic procedure. The crystal structure has triclinic space group P-1 with a = 5.8292(6) Å, b = 7.3039(7) Å, c = 17.9798(18) Å, α = 84.272(8)°, β = 89.184(8)°, γ = 81.469(8)°, and Z = 4. Intramolecular O–H?O and intermolecular O–H?O, N–H?N, N–H?O hydrogen bonds were determined in the crystal structure. In addition, there is a weak C–H?π interaction. Complexation on the periphery to yield tri-nuclear Zn(II)Pcs (5–7) was performed through the reaction of a Schiff base-substituted phthalocyanine (4) with MnCl₂·4H₂O, CoCl₂·6H₂O, or Ni(OAc)₂ salts. Fourier transform infrared, ¹H NMR, ¹³C NMR, UV–Vis, ICP-OES (inductively coupled plasma optical emission spectroscopy), mass spectroscopies, and elemental analyses were applied to characterize the prepared compounds. Bleach catalyst activity of the prepared phthalocyanine complexes (5–7) was examined by the degradation of morin and curcumin, respectively. The catalysts had better activity for color removing in solutions at ambient temperature than to that of tetraacetylethylenediamine (TAED).     

Spiral‐Type Heteropolyhedral Coordination Network Based on Single‐Crystal LiSrPO4: Implications for Luminescent Materials

Novel structures of luminescent materials, which are used as light sources for next‐generation illumination, are continuously being improved for use in white‐light‐emitting diodes. Activator‐doped known structures are reported as habitual down‐conversion phosphors in solid‐state lightings and displays. Consequently, the intrinsic qualities of the existent compounds produce deficiencies that limit their applications. Herein we report a spiral‐network single‐crystal orthophosphate (LiSrPO₄) prepared in a platinum crucible with LiCl flux through crystal‐growth reactions of SrCl₂ and Li₃PO₄ in air. It crystallizes in a hexagonal system with a=5.0040(2) and c=24.6320(16) Å, V=534.15(5) ų, and Z=6 in the space group P6₅. The unit cell is comprised of LiO₄ and PO₄ tetrahedrons that form a three‐dimensional LiPO₄^2? anionic framework with a helical channel structure along the c axis in which the Sr²⁺ cation is accommodated. The optical band gap of this composition is about 3.65 eV, as determined by using UV/Vis absorption and diffuse reflection spectra. We used the crystal‐growth method to synthesize blue‐ and red‐emitting crystals that exhibited pure color, low reabsorption, a large Stokes shift, and efficient conversion of ultraviolet excitation light into visible light. Emphasis was placed on the development of gratifying structure‐related properties of rare‐earth luminescent materials and their applications.     

Structural and physico-chemical characteristics of tetraethylammonium tetrachloridoferrate(III)

The crystal structure of tetraethylammonium tetrachloridoferrate(III) was determined. The crystals are hexagonal, space group P6₃ mc, a = 8.198(1) Å, b = 8.198(1) Å, c = 13.183(3) Å, V = 767.3(2) Å³, Z = 2. The asymmetric unit of [(C₂H₅)₄N][FeCl₄] consists of half each of a tetraethylammonium cation and a tetrachloridoferrate(III) anion. Tetrachloridoferrate(III) ion adopts almost ideal tetrahedral geometry. Structural characterization of the compound is supplemented by the results of its magnetic susceptibility measurements and electron paramagnetic resonance (EPR) spectra. Magnetic measurements of a powdered [(C₂H₅)₄N][FeCl₄] sample gave a negative Weiss constant of ?1.57, which suggests antiferromagnetic coupling. The susceptibility curve of [(C₂H₅)₄N][FeCl₄] against temperature exhibits a maximum, indicating the presence of antiferromagnetic ordering with a Neel temperature of approximately 2.9 K.     

Synthesis of Some Octahedral Nickel(II) Complexes of One Isomer of Isomeric Me8[14]anes: X-ray Structure of Diisothiocyanato(3,10-C-meso-3,5,7,7,10,12,14,14-octamethyl-1,4,8,11-tetraazacyclotetradecane, LC)nickel(II), [NiLC(NCS)2]

One isomer, L_C of the isomeric Me₈[14]anes, L_A, L_B and L_C; on reaction with Ni(NCS)₂ produces a six coordinate octahedral diisothiocyanato complex, [NiL_C(NCS)₂]. This complex undergoes axial substitution reactions with the small ligands to yield corresponding monosubstituted derivatives having general formula [NiL_C(NCS)X] whereas X = Cl, Br, I, NO₂ or NO₃. The complexes have been characterized on the basis of analytical, spectroscopic, magnetic and conductance data. The structure of [NiL_C(NCS)₂] (triclinic, space group P?1, α = 8.0421(17) Å, β = 8.9085(18) Å, χ = 9.687(2) Å, α = 67.561(3) Å, β = 82,896(4) Å, ζ = 598.7(2) Å³, Z = 2, Dc = 1.352 mg/m³, μ(Mo Kα) = 1.003 mm^?1) was confirmed by X-ray crystallography.     

The gas-phase structure of bis(fluorosulfonyl)difluoromethane, (SO2F)2CF2

New synthetic pathways and the infrared spectrum of bis(fluorosulfonyl)difluoromethane, (SO₂F)₂CF₂, are reported. The geometric structure and conformational properties of the title compound have been studied by gas electron diffraction. Depending on the rotational position of the two SO₂F groups, four conformers with different symmetries can occur in this compound: C_2v symmetry, if both S? F bonds stagger the CF₂ group. C₂ or C_s symmetry, if one S?O bond of each group staggers the CF₂ group. The experimental electron diffraction intensities can be fitted equally well with a C₁ conformer or with a mixture of C_2v, C₂ and C_s conformers, in a ratio of 3:2:5. The following geometric parameters (r_a distances, ∠_α angles with 3σ uncertainties) were derived: C? F = 1.340(6) Å, S?O = 1.412(2) Å, S? F = 1.550(3) Å, C? S = 1.848(4) Å, S? C? S = 113.6(7)°, F? C? F = 110.0(10)°, O?S?O = 124.6(18)°, C? S? F = 96.5(16)° and C? S?O = 108.4(14)°.     

New Borate‐citrate: Synthesis,Structure, and Properties of Sr[B(C6H5O7)2](H2O)4·3H2O

Single crystals of Sr[B(C₆H₅O₇)₂](H₂O)₄ · 3H₂O, a new borate‐citrate material, were grown with sizes up to 8 × 6 × 2 mm by slow evaporation of water at room temperature. The structure of Sr[B(C₆H₅O₇)₂](H₂O)₄ · 3H₂O was determined by single‐crystal X‐ray diffraction. It crystallizes in the monoclinic space group P2₁/c, with a = 11.363(3) Å, b = 18.829(4) Å, c = 11.976(3) Å, β = 110.736(3)°, and Z = 4. The SrO₈ dodecahedra, BO₄ tetrahedra and citrate groups are linked together to form chains. The compound was characterized by IR and UV/Vis/NIR transmittance spectroscopy as well as thermal analysis.