Sterically Crowded Hexaalkyl Benzene-1,2,3,4,5,6-hexakis[α-(alkoxycarbonyl)propanoates]. Synthesis and Conformation Analysis

2000 ◽  
Vol 65 (5) ◽  
pp. 673-694 ◽  
Author(s):  
Daniel Alexander ◽  
Stanislav Böhm ◽  
Ivana Císařová ◽  
Petr Holý ◽  
Jaroslav Podlaha ◽  
...  
Keyword(s):  
Single Crystal ◽  
Theoretical Calculation ◽  
High Yield ◽  
Conformation Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Broad Variety ◽  
Subsequent Replacement

A selective hexa-fold monoalkylation of the malonester carbanion (-)CH(COOR)2 (R = Me, Et, t-Bu, Bn) with hexakis(bromomethyl)benzene afforded the title compounds 3 in a high-yield reactions. On subsequent replacement of the acid α-hydrogens with bulkier substituents, the title compounds 3, R = Et, provided a broad variety of the α-X-persubstituted homologues and derivatives 4 (X = Me, Et, Bu, Oc, Bn, Br, N3). The effect of the variable X substituent on conformation was investigated by single-crystal X-ray diffraction and compared with the results obtained by theoretical calculation.

Synthesis of Triferrocenylbenzenes by Tantalum(V)-Catalyzed Cyclotrimerization of Ethynylferrocene. The Crystal Structure of 1,3,5-Triferrocenylbenzene

1997 ◽  
Vol 62 (10) ◽  
pp. 1577-1584 ◽  
Author(s):  
Petr Štěpnička ◽  
Ivana Císařová ◽  
Jan Sedláček ◽  
Jiří Vohlídal ◽  
Miroslav Polášek
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Single Crystal ◽  
High Yield ◽  
Isomer Mixture ◽  
State Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Yield Formation

Exclusive, high-yield formation of the cyclotrimers of ethynylferrocene (1) was observed when TaCl5 in benzene was employed as catalyst. Analysis of the resulting isomer mixture by means of HPLC and 1H NMR revealed the presence of 1,3,5-triferrocenylbenzene (sym-2) and 1,2,4-triferrocenylbenzene (asym-2) in the ratio of 4 : 6. A small amount of pure sym-2 isomer was isolated, and its solid-state structure was established by single-crystal X-ray diffraction. The molecules of sym-2 possess a distorted up-up-down arrangement of the ferrocenyl groups attached to the benzene ring.

scholarly journals SYNTHESIS AND STRUCTURE OF TWO PALLADIUM(II) COMPLEXES BEARING ACETONITRILE AND N-HETEROCYCLIC CARBENE DERIVED FROM IMIDAZOLE

2019 ◽  
Vol 57 (4) ◽  
pp. 468
Author(s):  
Mai Thi Cam Truong ◽  
Chi Thi Thanh Nguyen
Keyword(s):  
Single Crystal ◽  
Diffraction Study ◽  
13C Nmr ◽  
Nmr Spectra ◽  
High Yield ◽  
13C Nmr Spectra ◽  
Trans Position ◽  
X Ray Diffraction ◽  
Imidazolium Chloride ◽  
X Ray

The reaction of [PdCl2(CH3CN)2] (1) with either 1,3-bis(2,4,6-trimethylphenyl)imidazolium chloride (IMes·HCl) or 1,3-bis(2,6-diisoproylphenyl)imidazolium chloride (IPr·HCl) in the present of Ag2O afforded two mixed monocarbene-CH3CN complexes, namely trans-[PdCl2(CH3CN)(IMes] (2) and trans-[PdCl2(CH3CN)(IPr)] (3), with the high yield (85-90%). The structure of 2 and 3 were elucidated by ESI mass, IR, 1H NMR and 13C NMR spectra. For 2, single-crystal X-ray diffraction study was also carried out. The results show that the CH3CN in 2 and 3 coordinates with Pd(II) via the N atom, the deprotonated imidazolium salts are bound up with Pd(II) via the C atom (NCHN) and occupy trans-position in comparison with the CH3CN.

Analysis of Twin Boundary in Single Crystal of Ni-Mn-Ga Martensite Using Powder Laboratory Diffractometer

2013 ◽  
Vol 203-204 ◽  
pp. 13-16
Author(s):  
Jan Drahokoupil ◽  
Ladislav Straka ◽  
Oleg Heczko
Keyword(s):  
Single Crystal ◽  
Theoretical Calculation ◽  
Diffraction Study ◽  
Twin Boundary ◽  
Full Description ◽  
X Ray Diffraction ◽  
Beam Position ◽  
X Ray ◽  
Martensitic Microstructure ◽  
Standard Powder

The presented paper describes X-ray diffraction study of Ni-Mn-Ga modulated martensite single crystal. A standard powder laboratory diffractometer equipped with texture cradle and monocapillary was found to be suitable and sufficient tool for this type of studies. Three different scans were performed to unambiguously identify the martensitic twin variants at selected place. From this identification and with the help of theoretical calculation full description of martensitic microstructure can be determined. In addition the effect of sample displacement on beam position on sample was derived.

Chemistry of the Podocarpaceae. LXXII. Ring-C Modifications of Totarol

1988 ◽  
Vol 41 (8) ◽  
pp. 1171 ◽  
Author(s):  
RC Cambie ◽  
GR Clark ◽  
CEF Rickard ◽  
PS Rutledge ◽  
GR Ryan ◽  
...  
Keyword(s):  
Single Crystal ◽  
High Yield ◽  
The Novel ◽  
X Ray Diffraction ◽  
Lithium Iodide ◽  
Rearrangement Product ◽  
Ring Systems ◽  
X Ray ◽  
Naturally Occurring

Totarol (1) has been converted into conjugated dienolides which have the B/C-ring systems found in naturally occurring nagilactones A and C and their analogues. Thus, treatment of the epoxide (11) with titanium(IV) tetrachloride affords the desired 7,9(11)- diene (12) and the saturated γ- lactone (23). Treatment of the epoxide (11) with diazabicyclo [3.4.0]non-5-ene gives a high yield of the butenolide (24); the alcohol (25) has been shown to be an intermediate in this reaction. Treatment of (11) with lithium iodide dihydrate in collidine gives the butenolides (24) and (26), and the novel rearrangement product (27) which is slowly converted on standing into the epoxide (29). Treatment of (11) with anhydrous lithium iodide gives the α- pyrone (30). The structures of compounds (11), (23), (24) and (29) have been determined by single-crystal X-ray diffraction measurements.

scholarly journals Acid catalyzed cyclodimerization of 2,2-bis(trifluoromethyl)-4-alkoxy-oxetanes and -thietanes. Synthesis of 2,2,6,6-tetrakis(trifluoromethyl)-4,8-dialkoxy-1,5-dioxocanes and 3,3,7,7-tetrakis(trifluoromethyl)-9-oxa-2,6-dithia-bicyclo[3.3.1]nonane

2010 ◽  
Vol 6 ◽  
Author(s):  
Viacheslav A Petrov ◽  
Will Marshall
Keyword(s):  
Single Crystal ◽  
High Yield ◽  
X Ray Diffraction ◽  
X Ray ◽  
Acid Catalyzed ◽  
Yield Formation ◽  
Spontaneous Reaction

Treatment of 2,2-bis(trifluoromethyl)-4-R-oxetanes (R = C2H5O, n-C3H7O, n-C4H9O) with BF3·OEt2 in CH2Cl2 solvent results in spontaneous electrophilic [4 + 4] cyclodimerization with the formation of the corresponding 2,2,6,6-tetrakis(trifluoromethyl)-4,8-dialkoxy-1,5-dioxocanes, isolated in 31–42% yield. The structures of two products (R = C2H5O and n-C3H7O) were established by single crystal X-ray diffraction. The corresponding oxetane carrying the bulky t-C4H9O group has different reactivity towards BF3·OEt2, slowly producing a mixture of two acyclic, unsaturated products. Clean and spontaneous reaction with alcohols is another interesting transformation of oxetanes described in this paper. The reaction leads to high yield formation of the corresponding acetals (CF3)2C(OH)CH2CH(OR)OR′. Structurally related 2,2-bis(trifluoromethyl)-4-R-thietanes (R = i-C3H7O, t-C4H9O and C2H5O) have different reactivity towards electrophiles. They are totally inert to the action of BF3·OEt2 and rapidly react with a protic acid (H2SO4) forming the same product, 3,3,7,7-tetrakis(trifluoromethyl)-9-oxa-2,6-dithia-bicyclo[3.3.1]nonane in 35–50% yield. The structure of this product was established by single crystal X-ray diffraction.

High-yield, regiospecific bis-functionalization of C70 using a Diels–Alder reaction in molten anthracene

2014 ◽  
Vol 50 (73) ◽  
pp. 10584-10587 ◽  
Author(s):  
Venkata S. Pavan K. Neti ◽  
Maira R. Cerón ◽  
A. Duarte-Ruiz ◽  
Marilyn M. Olmstead ◽  
Alan L. Balch ◽  
...  
Keyword(s):  
Single Crystal ◽  
Thermal Gravimetric Analysis ◽  
Alder Reaction ◽  
Diels Alder ◽  
High Yield ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diels Alder Reaction

A regiospecific bis-adduct of C70 with anthracene was prepared with unusually high yield (68%) by the Diels–Alder reaction in the absence of solvent (melt). The structure of the bis-adduct was an unexpected 12 o'clock isomer, as determined by single crystal X-ray diffraction, thermal gravimetric analysis (TGA) and spectroscopy.

scholarly journals Formation and structural characterization of a europium(II) mono(scorpionate) complex and a sterically crowded pyrazabole

2017 ◽  
Vol 73 (12) ◽  
pp. 1921-1925 ◽  
Author(s):  
Phil Liebing ◽  
Marcel Kühling ◽  
Josef Takats ◽  
Liane Hilfert ◽  
Frank T. Edelmann
Keyword(s):  
Single Crystal ◽  
Structural Characterization ◽  
Molar Ratio ◽  
High Yield ◽  
X Ray Diffraction ◽  
Isopropyl Group ◽  
X Ray

The reaction of EuI2(THF)2with potassium hydrotris(3,5-diisopropylpyrazolyl)borate (K[HB(3,5-iPr2pz)3] (= KTpiPr2, pz = pyrazolyl) in a molar ratio of 1:1.5 resulted in extensive ligand fragmentation and formation of the europium(II) mono(scorpionate) complex bis(3,5-diisopropyl-1H-pyrazole)[hydrotris(3,5-diisopropylpyrazolyl)borato]iodidoeuropium(II), [Eu(C27H46BN6)I(C9H16N2)2] or (TpiPr2)(3,5-iPr2pzH)2EuIII,1, in high yield (78%). As a typical by-product, small amounts of the sterically crowded pyrazabole derivativetrans-4,8-bis(3,5-diisopropylpyrazol-1-yl)-1,3,5,7-tetraisopropylpyrazabole, C36H62B2H8ortrans-{(3,5-iPr2pz)HB(μ-3,5-iPr2pz)}2,2, were formed. Both title compounds have been structurally characterized through single-crystal X-ray diffraction. In1, two isopropyl groups are each disordered over two orientations with occupancy ratios of 0.574 (10):0.426 (10) and 0.719 (16):0.281 (16). In2, one isopropyl group is similarly disordered, occupancy ratio 0.649 (9):0.351 (9).

A Vanadyl(V) Complex with a Pincer-type Thiobis(phenolate) and an Acetylacetonate Co-ligand, VO(tbp)(acac)

2010 ◽  
Vol 65 (12) ◽  
pp. 1457-1461 ◽  
Author(s):  
Rahman Bikas ◽  
Hassan Hosseini Monfared ◽  
Somayeh Alami ◽  
Ingo Pantenburg ◽  
Gerd Meyer
Keyword(s):  
Single Crystal ◽  
Dimethyl Sulfoxide ◽  
Structure Analysis ◽  
Reduction Process ◽  
Vanadium Atom ◽  
High Yield ◽  
X Ray Diffraction ◽  
Cyclic Voltammetric ◽  
X Ray ◽  
Diffraction Structure

A new vanadyl(V) complex with the tridentate, pincer-type O,S,O-ligand thiobis(phenolate), tbp, was synthesized from the reaction of vanadium(IV) oxide bis(acetylacetonate), VO(acac)2, and 2,2’- thio-bis(4-methylphenol), H2tbp, in refluxing methanol in high yield. Single-crystal X-ray diffraction structure analysis revealed for VO(tbp)(acac) that the vanadium atom is octahedrally coordinated with an O5,S-donor environment where the thiobis(phenolate) ligand is O,S,O-bonded to the vanadyl(V) center facially in a tridentate dinegative fashion. Cyclic voltammetric experiments carried out with its solution in dimethyl sulfoxide revealed an irreversible peak at −0.768 V (vs. Ag/AgCl) relating to the V5+/V4+ reduction process.

Electron Microscopy of Shock Loaded Polycrystalline Beryllium

1974 ◽  
Vol 32 ◽  
pp. 506-507 ◽  
Author(s):  
J. M. Galbraith ◽  
L. E. Murr ◽  
A. L. Stevens
Keyword(s):  
Electron Microscopy ◽  
Wave Propagation ◽  
Structural Change ◽  
Single Crystal ◽  
Diffraction Pattern ◽  
Shock Loading ◽  
Slip Systems ◽  
Compression Tests ◽  
X Ray Diffraction ◽  
X Ray

Uniaxial compression tests and hydrostatic tests at pressures up to 27 kbars have been performed to determine operating slip systems in single crystal and polycrystal1ine beryllium. A recent study has been made of wave propagation in single crystal beryllium by shock loading to selectively activate various slip systems, and this has been followed by a study of wave propagation and spallation in textured, polycrystal1ine beryllium. An alteration in the X-ray diffraction pattern has been noted after shock loading, but this alteration has not yet been correlated with any structural change occurring during shock loading of polycrystal1ine beryllium.This study is being conducted in an effort to characterize the effects of shock loading on textured, polycrystal1ine beryllium. Samples were fabricated from a billet of Kawecki-Berylco hot pressed HP-10 beryllium.

Crystal structure of an inclusion complex between chiral monoaza-15-crown-5 and S(–)-1-phenyl-ethyl ammonium percholorate

2003 ◽  
Vol 218 (5) ◽  
Author(s):  
Süheyla Özbey ◽  
F. B. Kaynak ◽  
M. Toğrul ◽  
N. Demirel ◽  
H. Hoşgören
Keyword(s):  
Crystal Structure ◽  
Inclusion Complex ◽  
Single Crystal ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
New Type

AbstractA new type of inclusion complex, S(–)-1 phenyl ethyl ammonium percholorate complex of R-(–)-2-ethyl - N - benzyl - 4, 7, 10, 13 - tetraoxa -1- azacyclopentadecane, has been prepared and studied by NMR, IR and single crystal X-ray diffraction techniques. The compound crystallizes in space group

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