Synthesis and crystal structure of β-hexanitrohexaazaisowurtzitane

A polycyclic caged compound with high strain——hexanitrohexaazaisowurtzitane (HNIW)——has been synthesized via a three-step reaction: condensation, hydrogenolysis debenzylation and nitrolysis, starting with benzylmine and glyoxal. HNIW is the most powerful high energy density compound (HEDC) ever tested. β-HNIW possesses a caged structure consisting of two five-membered rings and one six-membered ring with a nitro group attached to each of the six bridging nitrogens. The nitro group lies basically within a plane. The lengths of C--C bonds of β-HNIW range from 0.156 nm to 0.159 nm, 0.002--0.005 nm longer than the sp~3 C-C bond. The β-HNIW's crystal belongs to orthorhombic system and space group Pca2_1 with parameters: a=0.9670 (2), b=1.1616 (2), c=1.3032 (3) nm; V=1.4638(5) nm~3, Z=4; D_c=1.989 g/cm~3 and D_m=1.982 g/cm~3.     

Synthesis and structure of β-aryl-α-nitroacrylates

The method for preparation of ethyl α-nitrocinnamates by nitroacetic acid ester alkenylation with aromatic aldehydes in the presence of acetic acid and β-alanine has been modified. Structures of the prepared compounds have been proved by electronic, IR, ¹H, and ¹³C-{¹H} NMR spectroscopy (including heteronuclear correlation experiments ¹H-¹³C HMQC and ¹H-¹³C HMBC). In solution these compounds exist in the form of Z-isomer; the Z?E isomerization is observed in the case of the compound containing strong electron-donor group [N(CH₃)₂] at benzene ring.     

Synthesis and x-ray crystal structure of a stable α-chlorooxetane

The Barton modification of the Hunsdiecker reaction is the key step in the preparation of 3,5-anhydro-5R-chloro-1,2-O-isopropylidenexylofuranose (1), a stable α-chlorooxetane.     

Synthesis and crystal structure study of 2′-Se-adenosine-derivatized DNA

The selenium derivatization of nucleic acids is a novel and promising strategy for 3D structure determination of nucleic acids.Selenium can serve as an excellent anomalous scattering center to solve the phase problem,which is one of the two major bottlenecks in macromolecule X-ray crystallography.The other major bottleneck is crystallization.It has been demonstrated that the incorporated selenium functionality at the 2′-positions of the nucleosides and nucleotides is stable and does not cause significant st...     

Synthesis and crystal structures of dichlorocyclopentadienyl β-diketonate titanium complexes

Complexes of acetylacetonatodichlorocyclopentadienyltitanium(IV) (1) and dichlorocyclopentadienyl(2,2,6,6-tetramethyl-3,5-heptanedionato)titanium(IV) (2) have been prepared and their crystal structures determined by X-ray diffraction methods. Complex 1 crystallizes in space group P2₁/m with a?=?7.1893(10), b?=?11.7680(17), c?=?7.6129(11) Å, β?=?109.901(12)°; complex 2 crystallizes in space group P2₁/n with a?=?10.065(2), b?=?16.322(3), c?=?12.219(2) Å, β?=?110.99(3)°. The molecular structures of 1 and 2 can be described as square-based pyramidal, with the centroid of the C₅H₅ ring occupying the apical site and the bidentate β-diketonate and two chloride ligands occupying the basal positions. The average distances between titanium and oxygen atoms are 1.991(2) and 1.967(3) Å in compounds 1 and 2, respectively.     

Synthesis and crystal structure of dinuclear nickel (Ⅱ) complex

The crystal structure of Ni(Ⅱ) complex with 3-hydroxyl-1, 5-diazacycloheptane-N, N'-diacetate was determined by X-ray diffraction method. Crystal data for Ni2 (C9H14N2O5)2·2H2O: monoclinic, space group P21/n, a = 1.1717(5), b = 0.9794(3), c = 1.2971(2) nm, β= 96.62(3), V= 1.4786(7) nm3, Dc = 1.377 g/cm3, Z = 2,μ=13.321 cm-1 (Mo-Kα), F(000)=640. The final R and Rw are 0.075 and 0.089 respectively. The Ni(Ⅱ) ion forms 2:2 complex with ligand. Two ligands are bridged by two Ni(Ⅱ) atoms which are bridged by two O atoms. Every Ni(Ⅱ) is coordinated by two N atoms and four 0 atoms. The coordination polyhedron of the Ni(Ⅱ) ion is a distorted octahedron.     

Xylyl derived oxacalixcrowns：Synthesis and crystal structure

Oxacalixcrowns 1, 2 and 3 were synthesized via reactions of dihydroxyoxacalix[2]arene[2]pyrazine 5 with ortho-, meta- and para-bis(bromomethyl)benzenes in a 1:1 fashion. The structures and conformations of 1, 2 and 3 were established by a combination of NMR, mass spectroscopies and single crystal X-ray diffraction analysis.     

Synthesis and crystal structure of pyridine and methanol coordinated a-octabutyloxyphthalocyaninatocobalt (II)

Phthalocyanines (Pcs) have been widely used as dyes and pigments, photoelectric materials and catalysts. They also bring general attention for potential applications, for example, in solar batteries and fuel cell, charge battery, electrochromic display devices, liquid crystal, sensors and molecular devices. The Pc抯 properties, such as spectroscopic, electronic, and magnetic properties, thermostabilities, and catalytic activities, may be adjusted by modifying the molecular structure. Therefor…     

Alkyl β-oxoalkanesulfonates: Synthesis and structure of methyl aroylmethanesulfonates

A number of new methyl esters of para-substituted benzoylmethanesulfonic acids was synthesized. An ability of both esters and salts to tautomeric transformations was examined. The esters were found to undergo an acid cleavage in alkaline medium.     

Synthesis and X-ray crystal structure of 3-deoxy-3-fluoro-β-D-allopyranoside

The synthesis of a novel compound, 3-deoxy-3-fluoro--d-allopyranoside, is described. It involves blocking the 4- and 6-positions of allose to cause fluorination only at the 3-position. This six-step synthesis gave pure crystalline compound in a 5% overall yield. The crystal structure, determined by X-ray diffraction, confirmed the chemical formula and configuration of the product. It showed that the C-F bond isaxial, while the C-(OH) bonds areequatorial. The overall conformation of this fluoroallose is similar to that of allose (Acta Cryst.1984,C40, 1863) (with OH instead of F), but the packing in the two crystals is different in the region of C3, the site of chemical variation.     

Synthesis and crystal structure of cyclotris-(4,4′-thiodiphenylene ketone)

The side reaction of macrocyclization that occurs during the synthesis of poly-(1,4-phenylenesulfide ketone) by polycondensation of a 4,4-dihalobenzophenone with sodium sulfide was studied. It was found that the major product of this reaction is a cyclic trimer, cyclotris-(4,4"-thiodiphenylene ketone) (1). Despite the fact that ketone bridges are more rigid than sulfide bridges, the yield of the macrocycle is rather high, as it is in the synthesis of poly-(1,4-phenylenesulfide), and reaches 20% under high dilution conditions. The structure of 1 was investigated by X-ray diffraction analysis (R = 0.069 on 3138 reflections). Macrocycle 1 is strongly flattened in the crystal; the conformation observed is determined by the packing, since stereochemical analysis indicates high flexibility of the macrocycle. The solvate acetone molecules incorporated in the crystal are disordered, nevertheless, they are strongly fixed in the cavities and channels of the crystal structure.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1460–1466, August, 1994.     

Synthesis and crystal structure of pyridine and methanol coordinated α-octabutyloxyphthalocyaninatocobalt (II)

Crystal structure of pyridine and methanol axially coordinated 1,4,8,11,15,18,22,25-octabutyloxyphthalocyaninatocobalt(II)(viz. α-octabutyloxyphthalocyaninatocobalt) [(n-BuO)₈Pc]. Co(Py)(MeOH) (1) was determined by X-ray diffraction methods. Crystal data: monoclinic, space group P2₁/n, Z = 4, a = 1.06482(4), b = 3.5487(2), c = 1.79428(9) nm, β=103.246(2)°, V = 6.5792(5) nm³, μ = 0.325 mm^-1. The result shows that the ring skeleton of 1 maintains planar conformation, which is similar to that of unsubstituted phthalocyanine but is remarkably different from the saddle shape conformation of 1,4,8,11,15,18,22,25-octabutyloxyphthalocyaninatocopper (II) [(n-BuO)₈Pc]Cu(2), which has no axial coordination. In the structure of 1, the substituents butyloxy groups of 1 somewhat deviate from the ring plane, while pyridine and methanol are coordinated to the center atom Co from opposite sides of the ring plane. In addition, all molecules are stacked along axis a to form one-dimensional molecule chain, the neighboring molecules in the chain overlap to some extent with a benzene ring and a distance of 0.3565 nm.     

Synthesis and study of cesium-containing phosphates with a β-tridymite structure

Complex phosphates CsMg_{1 ? x} M _x PO₄ (M = Mn, Co, Cu, Zn), containing cesium and metals in the oxidation state +2, have been synthesized, and their structure and thermal behavior have been studied. Continuous solid solutions (0 ?? x ?? 1) of the ??-tridymite structure type are formed in the CsMg_{1 ? x} Mn _x PO₄, CsMg_{1 ? x} Co _x PO₄, and CsMg_{1 ? x} Zn _x PO₄ systems, whereas limited solid solutions (0 ?? x ?? 0.4) are formed in the CsMg_{1 ? x} Cu _x PO₄ system. Based on DTA data, phase transitions have been revealed in the cobalt-, copper-, and zinc-containing phosphates, and the orthorhombic or monoclinic crystal system has been identified. Unit cell parameters of the solid solutions have been calculated. Thermal expansion of the CsMPO₄ phosphates has been studied.     

Synthesis and crystal structure of cobalt(III) α-dioximates with pyrazine

A series of new coordination compounds of cobalt(III) trans-dioximates with pyrazine [CoCl(DH)₂Pz] · H₂O (I), [CoBr(DH)₂Pz] · H₂O (II), [Co(DH)₂Pz₂]NO₃ · H₂O (III), [Co(DH)₂Pz₂][BF₄] (IV), [Co(MgH)₂Pz₂][BF₄] (V), and [Co(NioxH)₂Pz₂][BF₄] (VI), where DH, MgH, and NioxH are dimethylglyoxime, methylglyoxime, and 1,2-cyclohexanedionedioxime monoanions, respectively, Pz is a pyrazine molecule were synthesized. The structures of compounds I, II, and VI were determined by X-ray diffraction. The Co(III) environment in these compounds is octahedral and the pseudomacrocyclic (DioxH⁻)₂ fragment occurs in the equatorial plane. This fragment is stabilized by O-H…O hydrogen bonds. The neutral Pz ligand is monodentate in all three compounds.     

Synthesis and crystal structure of a 2nm long rectangular copper dimetallomacrocycle §

A new mixed-heterocycle ‘extended-reach’ ligand has been synthesized and used to prepare copper(II) and nickel(II) complexes. An X-ray crystal structure determination reveals that the copper complex is an M₂L₂ metallomacrocycle having an unusual rectangular shape with a length of over 2nm stabilized by intramolecular π-stacking.     

Preparation,characterization and crystal structure of N,N-dimethylanilinium β-octamolybdate dihydrate

N,N-dimethylanilinium β-ocatmolybdate dihydrate has been synthesized in acidic aqueous solution. The compound has been identified by using TG, DTG, IR and ¹H NMR techniques. It crystallizes in the triclinic system, space group PĪ, Z = 1, a = 11.755(3) Å, b = 11.836(5) Å, c = 10.498(2) Å, α = 105.29(2)°, β = 81.56(3)°, γ = 115.24(3)°, V = d1273.4(8) Å, D_o = 2.23(1) Mg m⁻³, D_x = 2.23 Mg m⁻³, R = 0.029 and R₂ = 0.032 for 5259 observed reflexions. Two crystallographically independent [C₈H₁₂N]⁺ cations, one water molecule and one centrosymmetric β-octamolybdate polyanion are present in the asymmetric unit. Hydrogen bonds of types NH ···O and OH···O seem to stabilize the structure.     

Synthesis,crystal structure and properties of two terbium complexes with 2,2′-bipyridine

Two new complexes {[Tb(2-IBA)₃ · 2,2′-bipy]₂ · C₂H₅OH} (1) and [Tb(2-ClBA)₃ · 2,2′-bipy]₂ (2) (2-IBA = 2-iodobenzoate; 2-ClBA = 2-chlorobenzoate; 2,2′-bipy = 2,2′-bipyridine) were prepared and their crystal structures determined by X-ray diffraction. Complex 1 is composed of two types of binuclear molecules, [Tb(2-IBA)₃ · 2,2′-bipy]₂ (a) and [Tb(2-IBA)₃ · 2,2′-bipy]₂ (b), and an uncoordinated ethanol molecule. In molecule (a), two Tb³⁺ ions are linked by four 2-IBA groups, all bidentate-bridging. In molecule (b), two Tb³⁺ ions are held together by four 2-IBA groups in two coordination modes, bidentate-bridging and chelating-bridging. In the two molecules, each Tb³⁺ ion is further bonded to one chelating 2-IBA group and one chelating 2,2′-bipy molecule, resulting in coordination numbers of eight for (a) and nine for (b). The structural characteristics of 2 are similar to that of molecule (b) in 1. The two complexes, 1 and 2, both emit strong green fluorescence under ultraviolet light with the ⁵D₄ → ⁷F _j (j = 6–3) emission of Tb³⁺ ion observed.