Mg2[BN2]Cl and Mg8[BN2]5I: Novel Magnesium Nitridoborate Halides — Syntheses,Crystal Structures,and Vibrational Spectra

The title compounds have been synthesized at 1473 K from stoichiometric mixtures of the binary components Mg₃N₂, MgX₂ (X = Cl, I) and BN in arc‐welded steel ampoules encapsulated in evacuated silica tubes. Mg₂[BN₂]Cl ( 1 ) and Mg₈[BN₂]₅I ( 2 ) crystallize in the orthorhombic space groups Pbca (no. 61) and Imma (no. 74), respectively, with a = 6.6139(8)Å, b = 9.766(1)Å, c = 10.600(1)Å, Z = 8 for 1 and a = 13.535(3)Å, b = 9.350(2)Å, c = 11.194(2)Å, Z = 4 for 2 . The crystal structures are characterized mainly by Mg₆ trigonal prisms which are condensed to 3D frameworks in different ways. Part of the trigonal prisms are centered by the [N—B—N]^3— anions and other voids in the framework by the X^— anions. The magnesium environment around Cl^— is a very distorted monocapped trigonal prism (CN = 6+1) and that of I^— is a bicapped heptagonal prism (CN = 14+2). The bond lengths and bond angles for the relevant [BN₂]^3— anions are d(B—N) = 1.330 — 1.338Å, ∠N—B—N = 175.8° in 1 and d(B—N) = 1.330 — 1.339Å, ∠N—B—N = 176.8° — 178.0° in 2 . The vibrational spectra of the title compounds have been recorded and interpreted based on the D_∞h symmetry of the relevant [N—B—N]^3— groups considering the site symmetry splitting.     

Structure of [4.4.4]propellane and [4.4.4]propellatriene by X-ray Analysis

The crystal structures of [4.4.4]propellane (monoclinic, a=12.053, b=7.832, c=13.001 Å, β=104.89°, space group C2/c, Z=4) and [4.4.4]propellatriene (monoclinic, a=7.876, b=12.651, c=13.164 Å, β=122.81°, space group P2₁/c,Z=4) have been determined by X-ray analysis. In propellane the six-membered rings are in the chair conformation, in propellatriene they adopt the ‘half-chair’ conformation with a twofold axis passing through the centre of each double bond. In both cases the observed parameters correspond to virtual D₃(32) molecular symmetry. Corrections have been applied for the effect of molecular libration. Strain-minimization calculations based on semi-empirical potential functions have been carried out and the molecular parameters so derived are compared with the experimental values.     

Syntheses and crystal structure studies of two compounds of quinolones

Two complexes with enoxacin and ciprofloxacin were synthesized and the crystal structures are reported. Compound 1, [Cu(H-Eno) · Cl₂] · 3H₂O (H-Eno = Enoxacin), crystallizes in the triclinic system, space group P 1, with lattice parameters a = 8.7731(12) Å, b = 9.4976(14) Å, c = 13.2033(19) Å, α = 86.319(7)°, β = 71.912(7)°, γ = 80.604(7)°, V = 1031.6(3) ų, Z = 2, D _c = 1.625 mgm^?3. 2, [Mn(Cip)₂] · 2H₂O (Cip = mono-anion of ciprofloxacin), crystallizes in the monoclinic, space group P2(1)/c, with lattice parameters a = 5.85690(10), b = 21.9490(6), c = 13.4443(3) Å, β = 100.9700(10)°, V = 1696.72(7) ų, Z = 2, D _c = 1.459 mgm^?3.     

The molecular structure of gaseous tetrafluoro-p-benzoquinone and tetramethyl-p-benzoquinone as determined by electron diffraction

The molecular structures of gaseous tetrafluoro-p-benzoquinone (p-fluoranil) and tetramethyl-p-benzoquinone (duroquinone) have been investigated by electron diffraction. Except for the methyl group hydrogen atoms, the molecules are planar to within experimental error, but small deviations from planarity are completely compatible with the data. Values for the geometrical parameters (r_adistances and r_α with parenthesized uncertainties of 2σ including estimated uncertainty in the electron wavelength and correlation effects, are as follows. Tetrafluoro-p-benzoquinone: D_2h symmetry (assumed); r(C0) = 1.211(6) Å, r(CC) = 1.339(12) Å, r(C-C) = 1.489(5') Å, r(C-F) = 1.323(5) Å, ∠C-C-C = 116.8(7)° and ∠C-C-F = 116.1(7)°. Tetramethyl-p-benzoquinone: C_2h symmetry (assumed);r(C-H) = 1.102(18) Å, r(CO) = 1.229(8) Å, r(CC) = 1.352(8) Å, r(C_sp2-C_sp2) = 1.491(11) Å, r(C_sp2-C_sp3) = 1.504(12) A, ∠C-CO-C = 120.8(8)°. ∠C-C-CH₃ = 116.1(8)°, ∠C-C-H = 110.5(34)° and α₁ = α₂ (methyl torsion = 30° (assumed).     

Strukturbestimmungen an Bor-Stickstoff-Verbindungen. V. Die Kristall- und Molekülstruktur des B-Tris(dimethylamino)-borazols

B-Tris(dimethylamino)borazine crystallizes in the monoclinic space group P2₁/a with a = 9.841, b = 17.61, c = 8.140 Å, β = 111.9°, and four molecules per unit cell. The molecule shows only small deviations from a planar structure of the symmetry D_3h. The endocyclic and exocyclic B? N bonds are equal within the standard deviation (mean value 1.432 Å). The ring angles are different at the B atoms and the N atoms.     

Neutron and X-ray diffraction study on polymorphism in lithium orthotantalate,Li3TaO4

The structures of the low-and high-temperature modifications of lithium orthotantalate, Li₃TaO₄, have been determined by neutron and X-ray diffraction methods. The low-temperature, or β, phase has symmetry $\text{C2}\text{c}$ and lattice parameters a₁ = 8.500(3), b₁ = 8.500(3), c₁ = 9.344(3)Å, and β = 117.05(2)°. The high-temperature, or α, phase has symmetry P2 and lattice parameters a_h = 6.018(1), b_h = 5.995(1), c_h = 12.865(2)Å, and β_h = 103.53(2)°. Both structures are ordered. The β-phase has a rock salt-type structure with a 3 : 1 ordering of the Li⁺ and Ta⁵⁺ ions. Its structure can be generated from the low-temperature modification by means of a complex pattern of shifts of the Ta⁵⁺ ions.     

Manifestations of noncovalent interactions in the solid state. Dimeric and polymeric self-assembly in imidazolium salts via face-to-face cation—cation π-stacking

Abstract

X-ray crystallographic investigation of the tertiary structure of simple 1-methylimidazolium (1-Meim) salts reveals that cation—cation face-to-face π—stacking with interplanar separations in the range typically seen for molecule—molecule and molecule—cation interactions are possible. Two salts are reported. 1-Meim-CF₃SO₃, 1, exists as a centrosymmetric dimer with an interplanar separation of only 3.16 Å. The two imidazolium rings are slipped to the extent that the interaction can be regarded as a manifestation of C—H…C—H dipole interactions. 1-Meim-NO₃ exists as a one-dimensional (1-D) polymer with interplanar separations of 3.65 Å. The cations are not as severely slipped as for 1 and the interactions can be regarded as the result of cation—cation and anion—anion complementary electrostatics. Semi-empirical calculations are used to rationalize the π-π stacking in both 1 and 2. Crystal data: 1-Meim-CF₃SO₃, 1, triclinic, P1, a=6.416(3) Å, b=7.617(4) Å, c=9.569(4) Å, α=85.36(4)°, β=86.08(3)°, γ=85.18(4)°, V=463.6(4) Å,³ Z=2, D_c =1.66 g cm^?3, μ=3.7 cm^?1, T=17°C, R=0.054 and R _w=0.076 for 1241 reflections; 1-Meim-NO₃, 2, monoclinic, P2₁/c, a=9.009(7) Å, b=9.988(6) Å, c=7.308(5) Å, β=94.93(6)°, V=655.2(8) Å,³ Z=4, D_c =1.47 g cm^?3, μ=1.2 cm^?1, T=17°C, R=0.060 and R _w=0.068 for 483 reflections.     

Complexation with diol host compounds. 13. Crystal structures and thermal analyses of inclusion compounds of 1,1,6,6-tetraphenylhexa-2,4-diyne-1,6-diol with cyclohexane,O-xylene,m-xylene and p-xylene

Abstract

It has been shown that host compound 1,1,6,6-tetraphenylhexa-2,4-diyne-1,6-diol is able to include polar guests and now we report on its ability to form clathrate compounds with apolar guests. The structures of this host with cyclohexane (1) and the ortho (2), meta (3) and para (4) xylenes have been determined and are discussed. Crystal data: (1) 2C₃₀H₂₂O₂C₆H₁₂, M _r = 913.20 g mol^?1, mono-clinic, C2/c, a = 22.851(6), b = 14.010(2), c = 17.076(6) Å, β = 108.71(3)°, V = 5178(2) ų, Z = 4, D _c = 1.17g cm^?3, N = 3326, R = 0.092. (2) 2C₃₀H₂₂O₂1 ½C₈H₁₀, M _r = 1976.5 g mol^?1, triclinic, P 1, a = 13.185(3), b = 15.466(3), c = 16.573(2) Å, α = 96.39(13)°, β = 106.96(15)°, γ = 114.94(18)°, V = 2822(2) ų, Z = 2, D _c = 1.16 g cm^?3, N = 6152, R = 0.075. (3) 2C₃₀H₂₂O₂1 ½C₈H₁₀, M _r = 1976.5 g mol^?1, triclinic, P 1, a = 13.267(5), b = 15.453(3), c = 16.654(5) Å, α = 97.12(2)°, β = 107.09(3)°, γ = 114.68(3)°, V = 2843(2) ų, Z = 2, D _c = 1.15 g cm^?3, N = 6505, R = 0.083. (4) 2C₃₀H₂₂O₂1 ½C₈H₁₀, M _r = 1976.5 g mol^?1, triclinic, P 1, α = 13.070(2), b = 15.348(3), c = 16.776(3) Å, α = 67.88<2)°, β = 74.27(1)°, γ = 65.29(1)°, V = 2817(1) ų, Z = 2, D _c = 1.15 g cm^?3, N = 6711, R = 0.050. Thermal analysis studies were also performed in order to examine their stability and the strength with which the guest species are held in the crystal lattice.     

Synthesis of two novel cobalt complexes and their crystal structures

Two new cobalt complexes were successfully synthesized from the reaction of binaphthyl Schiff base 2 with Co(OAc)₂ in the presence of sodium methoxide at 80 °C for 24 h and Co(acac)₃ in toluene under reflux. Their unique crystal structures are unambiguously disclosed by X‐ray analysis. Complex 3 is triclinic, space group P1 , unit cell dimensions a = 10.742(2) Å, b = 11.153(2) Å, c = 12.715 Å, α = 79.865(3) °, β = 76.053 °, γ = 72.532(4) °, volume 1401.3(5) ų, Z = 2. Complex 4 is triclinic, space group P1 , unit cell dimensions a = 10.801(2) Å, b = 12.554(3) Å, c = 15.219(3) Å, α = 105.672(4) °, β = 103.048 °, γ = 104.594(4) °, volume 1824.8(7) ų, Z = 2, calculated density 1.428 Mg m⁻³. Copyright © 2003 John Wiley & Sons, Ltd.     

Crystal structure and packing analysis of the liquid crystal dimer alpha,omega-bis(4-cyanobiphenyl-4-yloxy)octane

The crystal structure of the liquid crystal dimer α,ω-bis(4-cyanobiphenyl-4'-yloxy)octane has been determined from diffraction data obtained with synchrotron radiation. The structure is triclinic, with the space group P-1 with Z = 2 and the unit cell parameters are a= 7.135(5) Å, b= 12.811(5) Å, c= 15.639(5) Å, α= 75.800(5)°, β= 84.690(5)°, γ= 77.930(5)°. The flexible spacer linking the mesogenic groups is in the all-trans-conformation. Although the molecule has a potential centre of symmetry, it occupies a general position in the cell; this unusual behaviour has been investigated with the aid of a theoretical evaluation of the packing energy.     

Darstellung und Kristallstrukturen von (Ph3PNPPh3)2[Re2Br10] und (Ph4P)[Re2Br9]

Synthesis and Crystal Structures of (Ph₃PNPPh₃)₂[Re₂Br₁₀] and (Ph₄P)[Re₂Br₉] Depending on the molar ratio by reaction of [n-Bu₄N]₂[ReBr₆] with the Lewis acid BBr₃ in dichloromethane the bioctahedral complexes [n-Bu₄N]₂[Re₂Br₁₀] and [n-Bu₄N][Re₂Br₉] are formed. The X-ray structure determination on (Ph₃PNPPh₃)₂[Re₂Br₁₀] (monoclinic, space group C 2/c, a = 20.007(4), b = 15.456(5), c = 24.695(4) Å, β = 107.53(2)°, Z = 4) reveals a centrosymmetric edge-sharing complex anion with approximate D_2h symmetry and mean terminal and bridging Re–Br bond lengths of 2.453 (equatorial), 2.482 (axial) and 2.591 Å, respectively, and a Re–Re distance of 3.880 Å. (Ph₄P)[Re₂Br₉] (triclinic, space group P 1, a = 11.062(2), b = 12.430(3), c = 13.163(5) Å, α = 72.94(2), β = 68.47(2), γ = 82.09(2)°, Z = 2) contains a confacial bioctahedral anion with nearly D_3h symmetry and mean terminal and bridging Re–Br distances of 2.460 and 2.536 Å, respectively, and a Re–Re distance of 2.780 Å.     

The crystal structure of bicyclo [3.3.3]undecane-1,5-diol and the conformation of bicyclo[3.3.3]undecane (manxane)

The crystal structure of bicyclo [3.3.3]undecane-1,5-diol has been determined. It is monoclinic, P2₁/c, a = 12.99(2), b = 14.16(2), c = 12.50(1)A,β = 112.42(2)°, with two independent molecules in the asymmetric unit. One of these is disordered, but the other has almost exact C_3h symmetry and its conformation and precise molecular geometry agree well with previous calculations by molecular mechanics. The molecule shows considerable angle strain, having bridge angles in the range 118–121°     

Synthesis and crystal structure of (2.2.2-cryptand)potassium nitrate hydrate

(2.2.2-Cryptand)potassium nitrate hydrate, [K(Crypt-222)](NO₃) · 1.5H₂O (I) was synthesized and studied by X-ray diffraction method. Crystals I are triclinic (space group P ī, a = 11.262 Å, b = 12.033 Å, c = 12.181 Å, α = 60.48°, β = 86.17°, γ = 66.20°, Z = 2). The structure was solved by the direct method and refined by the full-matrix least-squares method in anisotropic approximation to R = 0.065 from 3377 independent reflections (CAD-4 automated diffractometer, λMoK _α). In complex I, the host-guest complex cation [K(Crypt-222)]⁺ has approximate D ₃ symmetry. The coordination polyhedron of the K⁺ cation is a two-base-centered trigonal prism, which is slightly distorted toward antiprism. The disordered NO ₃ ^? anions and water molecules are united by hydrogen bonds into infinite chains along the x-axis.     

The Phase Diagram of the System [Ph4P]Br/BiBr3. Synthesis,Crystal Structure,Thermal Behaviour,and Vibrational Spectra of [Ph4P]3[Bi2Br9] · CH3COCH3 and two Modifications of [Ph4P]4[Bi6Br22]

The phase diagram of the system [Ph₄P]Br/BiBr₃ was investigated with the aid of DSC, TG and temperature dependent X‐ray powder diffraction measurements. By varying the reaction conditions, stoichiometry and crystallisation conditions of the reaction between BiBr₃ and [Ph₄P]Br four polynuclear bromobismuthates are formed. We report here the crystal structure of the solvation product [Ph₄P]₃[Bi₂Br₉] · CH₃COCH₃, which crystallises with monoclinic symmetry in the S. G. P2₁/n No. 14, a = 12.341(1), b = 32.005(3), c = 19.929(3) Å, β = 99.75(2)°, V = 7758(7) ų, Z = 4 and the crystal structures of two modifications of the compound [Ph₄P]₄[Bi₆Br₂₂]. The α‐form, crystallises with triclinic symmetry in the S. G. P1 No. 2, a = 13.507(4) Å, b = 14.434(4) Å, c = 17.709(5) Å, α = 81.34(2)°, β = 72.42(2)°, γ = 72.53(2)°, V = 3132.7(1) ų, Z = 2. The high‐temperature β‐form, crystallises with triclinic symmetry in the S. G. P1 No. 2, a = 13.893(4) Å, b = 14.267(3) Å, c = 16.580(3), α = 100.13(2)°, β = 96.56(2)°, γ = 110.01(2)°, V = 2985.5(1) ų, Z = 2. Lattice parameters of [Ph₄P]₄[Bi₈Br₂₈] are also given. The thermal behaviour of the compounds and in addition the vibrational spectra of [Ph₄P]₃[Bi₂Br₉] · CH₃COCH₃ are presented and discussed.     

Synthese und Struktur der Kronenetherkomplexe von Kaliumhexachlorodipalladat(II) und -diplatinat(II)

Synthesis and Structure of Crown Ether Complexes of Potassium Hexachlorodipalladate(II) and -diplatinate(II) K₂[MCl₄] (M ? Pd, Pt) reacts with an excess of crown ether 18-crown-6 in water to give the crown ether complexes of potassium hexachlorodipalladate(II) and -diplatinate(II) [K(18-cr-6)]₂[M₂Cl₆] (M ? Pd, 1 ; M ? Pt, 3 ), respectively, and in methylene chloride to give those of potassium tetrachloropalladate(II) and -platinate(II) [K(18-cr-6)]₂[MCl₄] ( 1 ) (M ? Pd, 2 ; M ? Pt, 4 ), respectively. 1 - 4 are characterized by microanalysis, NMR (¹H, ¹³C), and vibrational spectroscopy. The X-ray structure analyses of the isotypic complexes 1 (P2₁/c; a = 10,9678(8), b = 8,2991(7), c = 22,469(2) Å, β = 98,523(5)°; Z = 2) and 3 (P2₁/c; a = 10,934(3), b = 8.376(3), c = 22,410(5) Å, β = 98,77(3)°; Z = 2) reveal [M₂Cl₆]^2? anions of nearly D_2h symmetry and [K(18-cr-6)]⁺ cations, in which the distance of K⁺ to the mean plane of the crown ether defined by its six oxygen atoms amounts to 0,830(4) Å in 1 and 0,821(2) Å in 3 , respectively. There are tight contacts between cations and anions (d(K-Cl): 3,341(2)/3,260(2) Å ( 1 ); 3,348(4)/3,259(4) Å ( 3 )).     

Reaction of Early Transition Metal Complexes With Macrocycles III. Synthesis and Structure of 18-Crown-6·l4 (M = Ti,Sn)

Abstract

18-Crown-6 reacts with either TiCl₄ or SnCl₄ in toluene to form an addition complex in which the macrocycle functions as a bidentate ligand. The two compounds are isostructural and belong to the monoclinic space group P2₁/n. For Ti. the cell parameters are a = 10.501(6), b = 18.104(5), c = 10.955(5) Å, β = 109.76(3)°, and D_c = 1.55 g/cm³ for Z = 4; for Sn, a = 10.572(9), b = 18.139(6), c = 11.056(5) Å, β = 109.16(4)°, and D_c = 1.75 g/cm³. Least-squares refinement led to a final R = 0.037 for 1735 observed reflections for the Ti complex, and R = 0.038 for 2940 observed reflections for the Sn derivative. The M-Cl lengths range from 2.221(2)–2.285(2) Å for M = Ti, and from 2.353(2)–2.357(2) Å for M = Sn. The M—O bonds are 2.102(4) and 2.138(4) Å for M = Ti, and 2.212(4) and 2.237(4) Å for M = Sn.     

Non‐Planar Lithium‐Phthalocyanine in the Double Salt (nBu4N)2[Lipc]PF6

We report the synthesis of the diamagnetic double salt bis(tetra(n‐butyl)ammonium) phthalocyanato(2‐)lithate hexafluorophosphate (nBu₄N)₂[Lipc]PF₆ [pc = phthalocyanine, nBu₄N⁺ = tetra(n‐butyl)ammonium] in dme (dme = dimethoxyethane). According to single‐crystal X‐ray diffraction structure analysis [P$\bar{1}$ , a = 8.642(2) Å, b = 12.820(3) Å, c = 15.019(3) Å, α = 83.01(3)°, β = 87.87(3)°, γ = 74.45(3)°, Z = 1, R₁ = 6.4 %], the phthalocyanine building bloc shows a substantial distortion of the macrocyclic ring from planarity. The deviation from D_4h symmetry originates from packing effects induced by the two tetra(n‐butyl)ammonium cations located above and below the macrocycle. DFT structure optimization starting from the experimental non‐planar configuration produces a fully planar complex anion [Lipc]^–.     

Syntheses and crystal structure studies of two zinc complexes of enoxacin

Two zinc complexes of enoxacin were synthesized and their crystal structures were determined. Compound 1, [Zn(H-Eno) · Cl₂] · 3H₂O (H-Eno = Enoxacin), crystallizes in the triclinic system, space group P 1, with lattice parameters a = 8.7731(12), b = 9.4976(14), and c = 13.2033(19) Å, α = 86.319(7)°, β = 71.912(7)°, and γ = 80.604(7)°, V = 1031.6(3) ų, Z = 2, D _Calcd = 1.631 Mg m^?3; compound 2, [Zn(H-Eno) · (H₂O)₂] · 2NO₃, also crystallizes in the triclinic system, space group P 1, with lattice parameters a = 8.751(2), b = 9.014(2), and c = 12.594(3) Å, α = 92.277(14)°, β = 109.867(12)°, and γ = 111.469(12)°, V = 854.1(3) ų, Z = 1, D _Calcd = 1.684 Mg m^?3.     

Molecular structure of the boron(III) oxide molecule in the SCF approximation

The potential surface for the boron(III) oxide (B₂O₃) ground state has been calculated in restricted HF approximation with a minimal STO—3G basis set. The equilibrium geometry has C_2v symmetry; the corresponding structural parameters are as follows: r(O_i—B₁)= 1.241 Å; r(B_i—O)= 1.341 Å ; ∠B₁QB₂ = 142° and ǒO₁B₁O = 177°. Calculations were also carried out using the SCF-Xα approach for two configurations of B₂O₃ with C_2v and D_∞h symmetry.     

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.