Showing papers in "Journal of Chemical Crystallography in 2005"

Single-crystal structure determination of a new polymorph (ε-Alq3) of the electroluminescence OLED (organic light-emitting diode) material, tris(8-hydroxyquinoline)aluminum (Alq3)

Abstract: Tris(8-hydroxyquinoline) aluminum, Alq3, is the most widely used electroluminescent material in organic light-emitting diode (OLED), chemistry. Single-crystal structure determination of a new polymorph of Alq3, designated as e-Alq3, is described. There are three molecules of Alq3 in the asymmetric unit. This octahedrally coordinated complex crystallizes in the triclinic space group P-1, lattice parameters a = 13.5190(5) A, b = 15.8550(6)~A, c = 18.7110(8) A, α = 95.4940(19)∘, β = 109.774(2)∘, γ = 114.6270(16)∘, Volume = 3296.8(2) A3, Z = 6, Z′ = 3.

Synthesis and structures of thienyl-substituted 5-dipyrromethane isomers

Abstract: The compounds 5(2-thienyl)-and 5(3-thienyl)-dipyrromethane (1 and2, respectively) have been synthesized and isolated from the acid-catalyzed reaction between thiophenes-carboxaldehyde and pyrrole. Characterization by X-ray diffraction confirms molecular structures involving twoortho-substituted pyrrolyl and one thienyl groups. Both the compounds1 and2 were crystallized in the monoclinic space groupP21/n with cell parametersa = 5.7149(16) A,b = 17.338(6) A, andc = 11.785(4) A, β = 98.466(9)∘,V = 1155.0(6) A3 for compound1; anda = 5.828(4) A,b = 17.424(10) A,c = 11.822(8) A, β = 98.10(2)∘, andV = 1188.4(13) A3 for compound2.

Structures of Nitroso- and Nitroguanidine X-ray Crystallography and Computational Analysis

Abstract: The X-ray structures of solid nitroguanidine (ngoH):orthorhombic, Fdd2, a = 176181(14), b = 24848(2), c = 35901(4) A, V = 15717(3) A3, Z = 16 and nitrosoguanidine (ngH); monoclinic, P 21/n, a = 364510(10), b = 11746(2), c = 86483(14) A, β = 99167(2)∘, V = 36555(9) A3, Z = 4 have been determined utilizing single crystal X-ray diffraction methods The results are compared with the most stable gaseous configurations derived from ab inito calculations The lowest energy calculated configuration for the ligands and experimentally observed crystal structures are in excellent agreement In the solid state, both the ngoH and ngH contain discrete molecules in their unit cells which are planar (within experimental error), in the diamine configurations and are structurally identical except for an oxygen atom In solid ngH, two ligand molecules have four nitrogen atoms arranged in a plane such that they are suitable for coordination to a nickel ion (1945, 2064 A), when it is at the 1/2, 1/2, 1/2 unit-cell position giving the observed complex As far as we are aware, this is the first instance in which a ligand crystal structure is essentially the same, with minor distance, angle and torsion angle changes, as the complex it forms and suggests some potentially unique properties and applications for this material

Synthesis and crystal structure of bis(malonato)tetra (aqua)barium(II)cobalt(II): [BaCo(C3H2O4)2(H2O)4]

Abstract: The title compound [BaCo(C3H2O4)2(H2O)4] was synthesized and its crystal structure was determined. The compound is orthorhombic, space group Pccn with a = 18.974(3) A, b = 6.783(2) A, c = 9.394(4) A. The structure is polymeric and consists of edge-sharing BaO8 polyhedra and CoO6 octahedra linked together by the malonate groups. The geometry around the Ba(II) centres is a slightly distorted square-antiprism with Ba–O distances ranging from 2.789(4) to 2.843(4) A. Around the Co(II) centres, the coordination forms a distorted octahedron with Co–O bonds between 2.040(3) and 2.238(4) A.

Synthesis and characterization of 9-(4-nitrophenyl)3,3,6,6-tetramethyl-3,4,6,7,9,10-hexahydro-1,8(2H,5H) acridinedione and its methoxyphenyl derivative

Abstract: 9-(4-Nitrophenyl)-3,3,6,6-tetramethyl-3,4,6,7,9,10-hexahydro-1,8(2H,5H) acridinedione (NTHA) crystallizes in orthorhombic space group P212121 with a = 5.9716(1) A, b = 18.0476(3) A, c = 19.2445(2) A, V = 2074.04(5) A3, Z = 4, Dcal = 1.263 Mg m−3 and R = 0.0521 (wR = 0.1326) for 4078 observed reflections. 9-(4-Nitrophenyl)-10-(4-methoxyphenyl)-3,3,6,6-tetramethyl-3,4,6,7,9,10-hexahydro-1,8(2H,5H) acridinedione NMTHA, crystallizes in monoclinic space group P21/c with a = 15.669(5) A, b = 10.652(4) A, c = 18.337(6) A, β = 108.25(1)∘, V = 2906.66(2) A3, Z = 4, Dcal = 1.245 Mg m−3 and R = 0.0725 (wR = 0.1847) for 5105 observed reflections. The experimental values are compared with the theoretical values calculated based on the semiemperical methods. The structures are stabilized by N–H⋅sO and C–H⋅sO types of intermolecular interactions in addition to van der Waals forces.

First example of lanthanide coordination polymer of 2,5-pyrazinedicarboxylate

Abstract: A lanthanum coordination polymer, [La(2,5-PZDC)1.5(H2O)] n , (2,5-PZDC = 2,5-pyrazinedicarboxylate) has been synthesized by using the reaction of LaCl3⋅7H2O with 2,5-pyrazinedicarboxylic acid under hydrothermal condition and structurally characterized by X-ray diffraction method. It crystallizes in the triclinic system P $$\bar 1$$ with a = 6.297(2) A, b = 6.762(2) A, c = 13.450(4) A, α = 82.984(5)∘, β = 83.164(5)∘, γ = 63.260(4)∘, V = 506.3(3) A3, Z = 2. The La3+ ion is nine-coordinate in a N2O7 environment, with a tricapped trigonal prism geometry, and the ligand 2,5-pyrazinedicarboxylate adopts two coordination modes, through which lanthanum ions are linked together to form a three-dimensional structure.

Crystal structure of 2,4,6-trinitropyridine and its N-oxide

Abstract: The structures of 2,4,6-trinitropyridine (TNPy) and its N-oxide were determined by X-ray single crystal diffraction. TNPy and 2,4,6-trinitropyridine-1-oxide (TNPyO) crystallize in space groupPbcn andPnma, respectively. The crystallographic parameters are as follows: TNPy,a = 28.573(6) A,b = 9.7394(19) A, andc = 8.7566(18) A, α = β = γ = 90∘, μ = 0.164 mm−1,V = 2436.8(8) A3,z = 12,Dx = 1.751 mg/mm3,F(000) = 1296,T = 293(2) K, 1.43∘≤ θ≤ 27.40∘, the finalR factor:R 1 = 0.0574,wR 2 = 0.1337. TNPyO,a = 9.6272(19) A,b = 14.128(3) A, andc = 5.9943(12) A, α = β = γ = 90∘, μ = 0.179 mm−1,V = 815.3(3)A3,z = 4,Dx = 1.875 mg/mm3,F(000) = 464,T = 293(2) K, 2.88∘≤ θ≤ 27.44∘, the finalR factor:R 1 = 0.0497,wR 2 = 0.1515.

Crystal structure, vibrational spectra and thermal decomposition of a new tetrazinc(II) dipyrophosphate decahydrate, Zn4(P2O7)2 ⋅10H2O

Abstract: A new zinc(II) pyrophosphate, Zn4(P2O7)2 ⋅10H2O, has been synthesized and characterized by single-crystal X-ray diffraction [orthorhombic space group Pnma, with unit cell parameters of a = 9.1508(2) A, b = 25.5271(5) A, c = 8.3574(2) A, Z = 4]. All the pyrophosphate anions show nonlinear P–O–P bonds with an average angle of 126.5∘. The framework of this new pyrophosphate is made up of packed layers of ZnO6 octahedra connected by double-tetrahedra P2O7 groups and a layer of Zn(H2O)6 units. The [P2O7]4− anions adopt a bent, near-staggered conformation. The absence of coincidences for the majority of the IR and Raman bands is in accord with the centrosymmetric structure of the material. The vibrational spectra have been interpreted in part on the basis of factor group effects. The structural changes occurring during heating have been investigated by TG-DSC, powder X-ray diffraction, and IR and Raman spectroscopy. When Zn4(P2O7)2 10H2O is gradually heated, it decomposes and γ-Zn2P2O7 is formed at 481∘C. On further heating, γ-Zn2P2O7 is transformed into β-Zn2P2O7 at 750∘C. The conversion between the γ and β-Zn2P2O7 forms is irreversible and, on cooling β-Zn2P2O7 to room temperature, it reverts back to α-Zn2P2O7. The crystal structure of the new zinc(II) pyrophosphate material is compared with the known structures of the related anhydrous products α-, β-, and γ-Zn2P2O7.

Synthesis and crystal structure of 1D 2,3-naphtho 15-crown-5 complex [Na(N15C5)] 2 [Ni(i-mnt) 2 ] containing S⋅ s C and S⋅ s π interactions

Abstract: The reaction of 2,3-naphtho-15-crown-5 (N15C5) with Na2[Ni(i-mnt)2] [i-mn = 1,1-dicyanoethylene-2,2-dithiolate] affords the title complex [Na(N15C5)]2[Ni(i-mnt)2] (1), which is characterized by elemental analysis, FT-IR, UV-visible spectra and single crystal X-ray diffraction. 1 crystallizes in the triclinic, space group P $$\bar{1}$$ with a = 8.291(4), b = 12.833(7), c = 12.913(6) A, α = 115.732 (7), β = 105.030(7), γ = 90.912(8)∘, V = 1182.2(10) A3, Z = 1 and R 1(wR 2) = 0.0422(0.1001). The single crystal X-ray analysis shows that the [Na(N15C5)]+ complex cations act as the bridges linking the [Ni(i-mnt)2]2− anions into a 1D infinite chain through Na–N interactions and S⋅sC and S⋅sπ interactions are observed in the chain with the shortest S⋅sC distance of 3.433 A.

Synthesis and structure of 7-methyl-5-phenyl-1H-pyrazolo[4,3-e]tetrazolo[4,5-b][1,2,4]triazine(1)

Abstract: The synthesis of 5-azido-3-methyl-1-phenyl-1H-pyrazolo[4,3-e][1,2,4]triazine 2 and 7-methyl-5-phenyl-1H-pyrazolo[4,3-e]tetrazolo[4,5-b][1,2,4]triazine 3 is described and the crystal and molecular structure of the latter is reported. This compound crystallizes in the monoclinic system, space group P21/n, with cell constants a = 11.607(2) A, b = 7.982(1) A, c = 13.147(2) A, β = 110.60(1)∘, Z = 4, T = 293 K and Dcal = 1.470 g cm−3. The structure was solved by direct methods and refined to R value of 0.0368 for 1906 reflections. The X-ray analysis revealed that the linear form of the tetrazolo-fused ring system of 3 exists in the crystal. The molecule as a whole has an almost planar conformation stabilized by the short intramolecular N⋅sH interaction. The molecular packing in the crystal is determined by the van der Waals forces only.

Crystal structure of [RuCl2[N-(2,4,6-trimethyl-benzyl)N-(n-butyl)]-imidazolidin-2-ylidene] and [RuCl2[N-(2,4,6-trimethyl-benzyl)-N-(2-methoxyethyl)]-imidazolidin-2-ylidene]

Abstract: Two imidazolidin ruthenium complexes, [RuCl2{[N-(2,4,6-trimethyl-benzyl)-N-(n-butyl)]-imidazolidin-2-ylidene}], 1, and [RuCl2{[N-(2,4,6-trimethyl-benzyl)-N-(2-methoxyethyl)]-imidazolidin-2-ylidene}], 2, have been synthesised and their crystal structures have been determined from single crystal X-ray diffraction data. Compound 1 is monoclinic, of space group C2/c with a = 18.466(4) A, b = 14.816(3) A, c = 15.413(3) A, β = 118.067(2)∘, and V = 3720.9(12) A3 with Z = 8 for dcalc = 1.536 g/cm3. Compound 2 is monoclinic, of space group P21/c with a = 8.1800(5) A, b = 14.344(8) A, c = 14.809(9), β = 91.604(10)∘, and V = 1736.7(18) A3 with Z = 4 for dcalc = 1.653 g/cm3. In each complex the ligand functions as an arene and carbene, occupying four coordination sites. The two chlorines in each compound complete a distorted octahedron.

Synthesis, characterization and crystal structure of oxovanadium(IV) complex with tridentate o-van-gly and bidentate phenanthroline

Abstract: A novel oxovanadium(IV) complex with tridentate schiff base and bidentate phenanthroline ligands, VO(o-van)(phen) ⋅2H2O[o-van-gly: o-vanillin-glycine; phen: phenanthroline], was synthesized and characterized by elemental analysis, IR and UV-vis spectra. The crystal structure was determined by X-ray single crystal diffraction analysis. The crystal of title complex (C22H21N3O7V, Mw = 490.36) belongs to triclinic, space group P-1 with the following crystallographic parameters: a = 9.247(3) A, b = 10.125(4) A, c = 13.100(5) A, α = 106.343(6)∘, β = 96.042(7)∘, γ = 101.726(7)∘, V = 1135.0(7) A3, Z = 2, Dc = 1.435 Mg ⋅ m−3, μ(MoK α = 0.485 mm−1, F(000) = 506, and final R1 = 0.0779, wR2 = 0.1598 for observed reflections 1606 (I > 2σ(I)). V(IV) is six-coordinate with three oxygen atoms and three nitrogen atoms in a distorted octahedral geometry. The complex forms a 3-D network via π–π stacking and hydrogen bonds.

Crystal structure of 1,7-dihydroxyxanthone from Weddellina squamulosa Tul

Abstract: 1,7-dihydroxyxanthone was isolated from Weddellina squamulosa Tul. (Podostemaceae) and the crystal structure has been determined (C13H8O4), Mr = 228.19, a = 4.902(1), b = 13.593(4), c = 14.740(2) A, space group P212121, Z = 4, and V = 982.2(4) A3. The 1,7-dihydroxyxanthone molecule is planar with a strong intramolecular H-bond O–H⋅sO [2.607(4) A]. The molecular packing is done through hydrogen bonds O–H⋅sO [2.786(4) A], forming channels along the direction parallel to the a-axis.

The crystal structure and thermal stability of [bis-picrate(pentaethylene glycol)] praseodymium(III)picrate complex

Abstract: [Bis-picrate(pentaethylene glycol)]praseodymium(III) picrate, [Pr(pic)2⋅(EO5]+[pic]−, was successfully obtained from the reaction of praseodymium nitrate hexahydrate, picric acid and pentaethylene glycol in acetonitrile–methanol as solvent. The crystal system is monoclinic with space group P21/c, a = 18.91419(11) A, b = 9.0470(6) A, c = 24.1209(14) A and α = γ = 90∘, β = 109.07(1)∘, V = 3880.3(4) A3 and Z = 4. The Pr atom is coordinated to the flexible and open EO5 ring via all the six oxygen atoms and two picrate ligands, one via phenoxo oxygen atom and the other one with both phenoxo and nitro oxygen atoms in a bidentate manner resulting a 9-coordinate tricapped trigonal prismatic geometry. The two picrate ligands coordinated to the Pr atom are at the opposite sides of the hexadentate EO5 ring with phenyl fragments almost perpendicular with dihedral angle of 89.7(3)∘. Thermal analysis results show that the complex is stable up to 100∘C when it began to slowly decompose and followed by an explosive decomposition at 290∘C.

The crystal structure of 1-phenyl-3-methyl-4(salicylaldehyde hydrazone)-propenylidene-5-pyrazolone

Abstract: The crystal structure of 1-phenyl-3-methyl-4-(salicylaldehyde hydrazone)-propenylidene-5-pyrazolone (PMPP-SH) was characterized by the single-crystal X-ray diffraction method. The cell parameters of PMPP-SH in the monoclinic P21/c space group are a = 10.851(1) A, b = 11.679 (1) A, c = 14.043 (2) A and β = 91.89 (1)∘. Analyzing the molecular structure suggest that, in the solid state, the title compound exists mainly in enaminopyrazolone form, which is stabilized by intramolecular hydrogen bonding, rather than NH-form.

Crystal structure, vibrational spectra and thermal decomposition study of a new, dicationic, acidic pyrophosphate: KHMgP2O7⋅2H2O

Abstract: Colourless crystals of a new, dicationic, hydropyrophosphate dihydrate salt, KHMgP2O7⋅ 2H2O, are formed, when a mixture of aqueous equimolar solutions of MgCl2⋅4H2O and K4P2O7, at pH 2.12, are left to stand at ambient temperature for 4 days. The new pyrophosphate salt has been characterized by single-crystal X-ray diffraction, IR and Raman spectra, and DSC-TG thermal analysis. The structure consists of alternating layers of [HP2O7]3− groups and MgO6 octahedra, joined by K+ ions and bridging hydrogen bonds. The [P2O7]4− anions exhibit a bent eclipsed conformation. The absence of coincidences for the majority of the IR and Raman bands is in accord with the centrosymmetric structure of the material. The 31P chemical shift tensor components have been determined from the solid-state MAS NMR spectra. The structural changes occurring during thermal decomposition have been examined by TG-DSC, X-ray powder diffraction (XRD) and IR spectroscopy. When the new pyrophosphate salt is heated gradually, it first becomes amorphous and then condenses to chain metaphosphates.

Nickel(II) complexes with N,N,O-donor Schiff bases. Self-assembly to two-dimensional network via hydrogen bonding

Abstract: The syntheses, characterization and crystal structures of two mononuclear nickel(II) complexes are described. Reactions of Ni(O2CCH3)2⋅4H2O with the Schiff bases derived from 2-pyridinecarbaldehyde and ortho-aminophenol (Hpaap) and 2-pyridinecarbaldehyde and ortho-aminobenzoic acid (Hpaab) in methanolic media afford the complexes in good yields. The elemental analysis, magnetic moments, and spectral features of the complexes are consistent with the formulae [Ni(paap)2]⋅CH3COOH⋅H2O and [Ni(paab)2]⋅2H2O. Crystal data for [Ni(paap)2]⋅CH3COOH⋅H2O: monoclinic, P21/c, a = 9.675(2) A, b = 17.109(5) A, c = 14.403(4) A, β = 92.903(11)∘, V = 2381.1(11) A3, and Z = 4 and for [Ni(paab)2]⋅2H2O: triclinic, P 1, a = 9.834(3) A, b = 11.319(3) A, c = 13.130(4) A, α = 84.68(3), β = 67.54(3), γ = 85.49(2)∘, V = 1343.4(6) A3, and Z = 2. In each complex, two tridentate monoanionic meridionally spanning ligands form a distorted octahedral N4O2 coordination sphere around the metal ion. In [Ni(paap)2]⋅CH3COOH⋅H2O, two metal coordinated phenolate-O atoms are hydrogen bonded to CH3COOH and H2O, respectively. Intramolecular C–H⋅ ⋅O interactions involving the water molecule and the C–H from azomethine and aromatic fragments lead to a two-dimensional network of [Ni(paap)2]⋅CH3COOH⋅H2O in the crystal lattice. An uncoordinated carboxylate O-atom in [Ni(paab)2]⋅2H2O is hydrogen bonded to both water molecules. One of the water molecules is again hydrogen bonded to the corresponding symmetry related water molecule forming a dimer. The azomethine groups and the metal coordinated carboxylate-O atoms in [Ni(paab)2] are involved in intermolecular C–H⋅ ⋅O interactions forming a chain-like arrangement of the molecules. The water dimers act as bridges between these chains and a two-dimensional network of [Ni(paab)2]⋅2H2O is formed.

Crystal structure of 1,5,8-trihydroxyl-3-methoxy xanthone from Swertia chirayita

Abstract: In order to study the relationship between biological and pharmacological activities with their structures, a series of tri-, tetra-oxygenated xanthones including 1-hydroxyl-2,3,4,7-tetramethoxy xanthone 1, 1-hydroxyl-2,3,4,5-tetramethoxyl xanthone 2, 1-hydroxyl-3,5-dimethoxy xanthone 3, 1,8-dihydroxyl-3,5-dimethoxyl xanthone 4, 1,5,8-trihydroxyl-3-methoxy xanthone 5 has been isolated from Swertia chirayita. Their structures were established on the basis of spectral and chemical evidence. The crystal structure of 5 was also investigated by single crystal X-ray diffraction analysis. It crystallizes in the triclinic system, space group P $$\bar{1}$$ , with a = 7.1540(10) A, b = 7.520(2) A, c = 10.671(2) A, V = 562.7(2) A3, α = 86.50(3)∘, β = 80.06(3)∘, γ = 85.00(3)∘, Z = 2, D c = 1.618 g m−3, R int = 0.0230, w R(F 2) = 0.1028, F(000) = 284. The molecular structure is nearly plane and four substituents are much closer to the plane of the molecule. Compound 5 also shows three intermolecular hydrogen bonds. A recent study shows that phenolic hydroxyls in xanthones are the main active groups capable of scavenging •OH and O2•.

Crystal structure, physical properties and Pt-195 NMR characterization of Pt(bipy)Br

Abstract: The complex dibromobipyridylplatinum(II), Pt(bipy)Br2, crystallizes in the monoclinic space groupC2/c witha = 17.262(5) A,b = 9.388(2) A,c = 7.557(2) A, β = 113.47(2)∘, andZ = 4. The complex is isomorphous to the monomeric copper derivative, Cu(bipy)Br2. The195Pt NMR spectrum shows the typical line broadening effect caused by coordinated nitrogen-14. The complex resonates at −1897 ppm with a half-height peak width of 1300 Hz. The structure is compared with the analogous structures Pt(bipy)(X)2 (X = Cl and I) and Pd(bipy)Br2.

Synthesis and crystal structure of 5-allyl-5Hdibenzo[b,f]azepine

Abstract: The crystals 5H-dibenzo[b,f]azepine 2 and 5-allyl-5H-dibenzo[b,f]azepine 3 were synthesized and characterized by X-ray crystallography. The compound 3 is a novel synthon for the construction of unusual isoxazoli(ne)dine rings bearing at the 5th position of dibenzo[b,f]azepine moiety. The compound 2 (C14H11N) crystallizes in the orthorhombic space group P212121 with the parameters a = 6.036(1) A, b = 8.250(7) A, c = 20.528(4) A, Z = 4 and the final R factor is R1 = 0.0544. The compound 3 (C17H15N) crystallizes in the Hexagonal space group P61 with the parameters a = 11.043(9) A, c = 18.575 A, Z = 6 and the final R factor is R1 = 0.0373.

Triethyl ammonium salt of O,O′-bis(p-tolyl)dithiophosphate, [Et3NH]+[(4-MeC6H4O)2PS2]−

Abstract: The X-ray structure of the triethyl ammonium salt of O,O′-bis(o-tolyl)dithiophosphate, [Et3NH]+[(2-MeC6H4O)2PS2]−, has been determined. Crystal data: Monoclinic, P21/c, a = 15.4342(6) A, b = 10.1913(4) A, c = 14.0729(6) A, β = 100.855(1)∘, V = 2174.0(2) A−3, Z = 4. The immediate environment around phosphorous is distorted tetrahedral with two sulfur and two oxygen atoms in the coordination sphere, with N–H–S bonding involving only one of the sulfur atoms.

Crystal structures of mollugin and lucidin

Abstract: Mollugin was isolated from the extract of Rubia tinctorum roots. Lucidin was obtained by semisynthesis from xanthopurpurin. Mollugin crystallises in space group P-1 (No. 2), a = 8.5857(7), b = 11.473(4), c = 15.024(1) A, α = 77.64(2)∘, β = 89.36(1)∘, γ = 89.71(2)∘, and V = 1445.5(5) A3, lucidin crystallises in space group P21/c (No.14), a = 16.800(6), b = 9.637(2), c = 7.073(7) A, β = 98.01(5)∘, and V = 1134(1) A3.

A new polymorph of tri(p-tolyl)boroxine

Abstract: A new orthorhombic polymorph of tri(p-tolyl)boroxine (Pmn21) with relatively short intermolecular B–O distances of 3.321 A was crystallized from CDCl3 at ambient temperature. The crystal structure of the orthorhombic polymorph of tri(p-tolyl)boroxine shows the shortest intermolecular B–O contact yet found in boroxines. The cell dimensions of the orthorhombic polymorph of tri(p-tolyl)boroxine are a = 21.888(4) A, b = 9.304(2) A, and c = 4.7804(10) A. The structural features of the orthorhombic polymorph of tri(p-tolyl)boroxine are quite different from a previously reported monoclinic (Beckett et al., J. Organomet. Chem. 1997, 535, 33–41) but similar to that of tri(p-bromophenyl)boroxine (Avent et al., Coll. Czech. Chem. Commun. 2002, 67, 1051–1060). Obviously, electronic effects of substituents on the boron centers influence the structural features of substituted boroxines less than discussed in earlier reports (Boese et al., Angew. Chem. 1987, 99, 239–241).

Synthesis and structural studies of tris-2-chlorobenzylamine and tris-2-bromobenzylamine

Abstract: The tris-2-chloro and 2-bromotribenzylamines are prepared from aqueous ammonia and 2-chlorobenzyl chloride and 2-bromobenzyl bromide, respectively, in ethanol. Recrystallization yielded colorless cubes of each product. The crystal structures are each solved in space group P $$\bar 1$$ , and are isostructural. The tris-2-chloro compound, 1, has a = 7.4226(5) A, b = 9.0825(7) A, c = 14.529(1) A, α = 78.279(1)∘, β = 82.389(1)∘, γ = 84.661(1)∘, and V = 948.41(12) A3 with Z = 2, and d calc = 1.368 Mg/m3. The tris-2-bromo analog, 2, has a = 7.6569(11) A, b = 9.0922(13) A, c = 14.614(2) A, α = 79.286(2)∘, β = 81.777(2)∘, γ = 85.401(2)∘, and V = 987.9(2) A3 with Z = 2, and d calc = 1.762 Mg/m3. Lithium–halogen exchange experiments conducted in tetrahydrofuran at −78∘C using n-butyl lithium revealed that no exchange occurred for the tris-2-chloro compound, but did occur for the tris-2-bromo analog to yield tribenzylamine upon quench and work-up.

Synthesis and crystal structure of a phthalate-bridged copper(II) complex {[Cu(L)(Phen)(H2O)]⋅H2O}n

Abstract: A phthalate-bridged copper(II) complex {[Cu(phth)(Phen)(H2O)] ⋅ H2O}n (H2phth: phthalic acid, Phen: 1,10-phenanthroline) has been synthesized by the reaction of CuCl2 and phthalic acid in the presence of 1,10-phenanthroline in aqueous solution The crystal structure of the complex has been determined by X-ray diffraction analysis to be orthorhombic, with the centrosymmetric space group Pbcm, where a = 116652(3) A, b = 111709(3) A, c = 140532(4) A, V = 183128(9) A3, Z = 4 The L2− (the acid radical of H2phth) ion is coordinated to the Cu2+ ion as a monodentate ligand Each L2− ion bridges two adjacent Cu2+ ions with its two oxygen atoms from two carboxylic groups to form a one-dimensional zigzag chain The coordination water and uncoordinated carboxylic oxygen atoms from neighboring chains are linked through hydrogen bonds to form a two-dimensional structure There is a weak interaction between the coordination water molecule and the Cu2+ ion in the neighboring chain

Synthesis, spectroscopic characterisation and X-ray structure of [trans-Co(en)2(NO2)2]2(Cr2O7)

Abstract: Dark red crystals of bis[trans-dinitrobis(ethylenediamine)cobalt(III)] dichromate, [trans-Co(en)2(NO2)2]2(Cr2O7) have been obtained by slowly allowing to mix the solutions of potassium dichromate and trans-dinitrobis(ethylenediamine)cobalt(III) nitrate in 1:2 molar ratio in aqueous medium. Elemental analyses and spectroscopic techniques (IR, UV/visible, 1H and 13C NMR) were used for characterizing the complex salt. The complex salt crystallizes in the orthorhombic space group Fdd2 with unit cell dimensions a = 24.778(2) A, b = 30.457(2) A, c = 6.5364(5) A, Z = 8, V = 4932.8(7) A3, R1 = 0.0617 and wR2 = 0.1518. X-ray structure determination revealed an ionic structure consisting of cationic cobaltammine [trans-Co(en)2(NO2)2]NO3 and dichromate anion. It is the first crystal structure of this cation with a dianion.

4-(E)-2-[3-(3-[(E)-2-(4-cyanophenyl)-1-diazenyl]hexahydro-1-pyrimidinylmethyl)hexahydro-1-pyrimidinyl]-1diazenylbenzonitrile: X-ray crystal structure

Abstract: 4-(E)-2-[3-(3-[(E)-2-(4-cyanophenyl)-1-diazenyl]hexahydro-1-pyrimidinylmethyl)hexahydro-1-pyrimidinyl]-1-diazenylbenzonitrile (1) has been synthesized by reaction of p-cyanobenzene diazonium chloride with a mixture of formaldehyde and 1,3-propanediamine. The crystal structure has been determined by single crystal X-ray diffraction analysis. The bis-triazene (1) adopts a folded conformation, similar to previously studied ethylenediamine analogues, and there is evidence of π-stacking in the crystal packing. The two planar phenyltriazenyl groups are almost parallel, forming an angle of 6.6(1)∘, and display weak intermolecular π ⋅s π interactions between molecules. This result establishes the structure of the product of this diazonium coupling reaction as the 1-(1-hexahydropyimidinylmethyl)hexahydropyrimidine derivative and not the alternate tetraazabicyclo[5.5.1]tridecane derivative. Crystal data: 1C23H26N10, monoclinic, space group P21/c, a = 10.717(1) A, b = 7.749(1) A, c = 28.252(2) A, β = 97.223(2)∘, V = 2327.5(5) A3, for Z = 4.

Synthesis and characterization of a lead(II) complex [Pb(phen)(H 2 O)(NO 3 ) 2 ] (phen = 1,10-phenanthroline)

Abstract: The monomeric lead(II) complex, [Pb(phen)(H2O)(NO3)2] was prepared by a hydrothermal reaction of Pb(NO3)2, nitrilotriacetic acid, NaOH, 1,10-phenanthroline, and H2O. The structure was determined by X-ray crystallography. It crystallizes in monoclinic P2(1)/n space group with the crystal cell parameters of a = 6.3568(6), b = 20.2345(19), c = 11.2722(9) A, β = 98.337(4)∘, V = 1434.6(2) A3, and Z = 4. The crystal X-ray analysis shows that the lead atom is six-coordinated by two N atoms of phen ligand, three oxygen atoms of nitrate anions and one water molecule. Owing to the presence of a lone pair of electrons of lead atom, a significant gap occurs in the coordination geometry around Pb ion. A 3D architecture is formed through the strong hydrogen bonding and π–π stacking interactions.

Hydrothermal synthesis and crystal structure of a new europium fumarate compound

Abstract: The complex {[Eu2F3⋅4H2O]⋅3H2O} n (H2F = fumaric acid) has been synthesized and structurally characterized by single crystal X-ray diffration methods. The complex crystallizes in the monoclinic system with space group P21/n, lattice parameters a = 9.475(3) A, b = 14.700(5) A, c = 14.810(4) A, α = 90∘, β = 91.250(5)∘, γ = 90∘, V = 2062.1(11) A3, Z = 4, Dcalc = 2.487 Mg/m3. The Eu(III) center is in distorted tricapped trigonal prism coordination environment that is coordinated by nine oxygen atoms, seven from five F2− groups, two from two water molecules. Eu(III) ions are connected into three-dimensional coordination network structure by the oxygen atoms of the carboxyl groups and hydrogen bonds.

Synthesis, characterization and crystal structures of dipyridyl-N-methylimine and cloro-bis (N,N?-2,2?-dipyridyl-N-methylimine)lithium complex

Abstract: The preparation and characterization by X-ray crystallography and NMR spectroscopy of the 2,2′-dipyridyl-N-methylimine (dpNmei) and the complex [cloro-bis(N,N′-2,2′-dipyridyl-N-methylimine)]lithium [Li(dpNmei)2(Cl)] is reported The dpNmei was prepared from the reaction of the 2,2′-dipyridyl ketone (dpk) and methylamine and crystallizes in the monoclinic P21/n space group with a = 63887(6), b = 101709(10), c = 167594(17) (A), β = 100918(2)∘ and V = 106929(18) A3 The lithium complex was obtained from the reaction of dpNmei and LiCl in a molar ratio 2:1 [Li(dpNmei)2Cl] crystallizes in the orthorhombic Pbcn space group with a = 100092(12), b = 98201(12), c = 23669(3) (A) and V = 23264(5) A3 The crystallographic data show that the lithium ion is five-coordinated with four coordination bonds N→Li due the chelation of dpNmei and one Li–Cl bond