Bifunctional bis(oxazolines) as potential ligands in catalytic asymmetric reactions

2004 ◽  
Vol 82 (2) ◽  
pp. 306-313 ◽  
Author(s):  
Stephen Hanessian ◽  
Eric Jnoff ◽  
Noemy Bernstein ◽  
Michel Simard
Keyword(s):  
Single Crystal ◽  
Key Words ◽  
Enantiomeric Excess ◽  
Asymmetric Reactions ◽  
Potential Utility ◽  
X Ray Diffraction ◽  
Asymmetric Addition ◽  
X Ray ◽  
Oxazoline Ligands ◽  
Cu Complexes

C2-symmetrical bis(oxazoline) ligands bearing pendant alkylthio ether groups were synthesized, and the structures of Cu complexes were determined by single crystal X-ray diffraction. The potential utility in catalysis was shown in the asymmetric addition of methyllithium to an aromatic aldimine, which resulted in a mixture of products with an enantiomeric excess of 68%.Key words: two-center catalysis, bis(oxazoline), aldimine, imine alkylation.

scholarly journals X-ray structure of hexamethyl benzenehexacarboxylate, [C6(COOCH3)6]

1970 ◽  
Vol 34 (2) ◽  
pp. 197-200
Author(s):  
Shishir Ghosh ◽  
Md Kamal Hossain ◽  
Shariff E Kabir ◽  
Noorjahan Begum
Keyword(s):  
Thermal Treatment ◽  
Single Crystal ◽  
Diffraction Study ◽  
Key Words ◽  
Spectroscopic Data ◽  
Monoclinic Space Group ◽  
Dimethyl Acetylenedicarboxylate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Academy Of Sciences

The thermal treatment of [Ru2(CO)6(μ-η1,η2-C4H3O){μ-P(C4H3O)2}] 1 with dimethyl acetylenedicarboxylate (DMAD) at 110 °C leads to cyclotrimerization of DMAD. The cyclotrimerization product hexamethyl benzenehexacarboxylate, [C6(COOCH3)6] 2, was obtained in 37% yield and characterized by a combination of spectroscopic data and single crystal X-ray diffraction study. Compound 2 crystallizes in the monoclinic space group P1bar with a = 10.3002(12), b = 11.0371(13), c = 18.781(2) Å, α = 76.148(2), β = 87.390(2), γ = 74.001(2)°, Z = 4 and V = 1992.2(4) Å3. Key words: Cyclotrimerization; Dimethyl acetylenedicarboxylate; X-ray structure DOI: 10.3329/jbas.v34i2.6866Journal of Bangladesh Academy of Sciences, Vol. 34, No. 2, 197-200, 2010

Arene–perfluoroarene interactions in crystal engineering. Part 14. 1:1 Complexes of octafluoronaphthalene with fluorene and 9,10-dihydrophenanthrene

2006 ◽  
Vol 84 (2) ◽  
pp. 238-242 ◽  
Author(s):  
Jonathan C Collings ◽  
Andrei S Batsanov ◽  
Judith AK Howard ◽  
Todd B Marder
Keyword(s):  
Single Crystal ◽  
Key Words ◽  
Crystal Engineering ◽  
Molecular Complexes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Face To Face ◽  
Π Stacking

The 1:1 molecular complexes of octafluoronaphthalene (OFN) with fluorene (1) and with 9,10-dihydrophenanthrene (2) were prepared by cocrystallization of the components and characterized by single-crystal X-ray diffraction. The structure of 1 can be described as a mixed-stack or a laminar checkerboard motif of alternating OFN and fluorene molecules, whilst slanted mixed-stack, herringbone, and face-to-face heteromolecular dimer motifs can all be recognised in 2.Key words: single crystal, X-ray structure, π stacking, fluoroarene.

A Planar-Chiral Pillar[5]arene-Based Monophosphine Ligand with Induced Chirality at the Biaryl Axis

Synlett ◽  
2018 ◽  
Vol 29 (16) ◽  
pp. 2167-2170 ◽  
Author(s):  
Yuuya Nagata ◽  
Tomoki Ogoshi ◽  
Michinori Suginome ◽  
Yasuo Shimada ◽  
Tsuyoshi Nishikawa ◽  
...  
Keyword(s):  
Single Crystal ◽  
Diffraction Analysis ◽  
Asymmetric Catalysis ◽  
Cd Spectroscopy ◽  
Asymmetric Reactions ◽  
Side Chains ◽  
Chiral Ligand ◽  
X Ray Diffraction ◽  
Chirality Transfer ◽  
X Ray

A planar-chiral pillar[5]arene with cyclohexylmethoxy side chains and a pendant diphenylphosphine was prepared and used as a chiral ligand in asymmetric reactions. Chirality transfer from the planar-chiral pillar[5]arene scaffold to the chiral biaryl moiety was demonstrated by circular dichroism (CD) spectroscopy, single-crystal X-ray diffraction analysis, and asymmetric catalysis.

Ternary cobalt germanium pnictides CoGexPn1-x (Pn = P, As, Sb) and the structure of Co3Ge2Sb, an intermetallic compound with stuffed Sb2 pairs

1998 ◽  
Vol 76 (11) ◽  
pp. 1588-1594 ◽  
Author(s):  
Allison M Mills ◽  
Robert Lam ◽  
Arthur Mar
Keyword(s):  
Crystal Structure ◽  
Intermetallic Compound ◽  
Single Crystal ◽  
Key Words ◽  
Intermediate Structure ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray

The ternary cobalt germanium pnictide systems CoGexPn1-x (Pn = P, As, Sb; 0 <x <1) were investigated. The ternary phosphides CoGexP1-x and arsenides CoGexAs1-x adopt the MnP structure (Pnma) in the range 0 <x <0.8, with Ge and Pn (Pn = P, As) disordering over the anion sites. Reactions in the antimonide system CoGexSb1-x result in a mixture of ternary phases, one with the NiAs structure (P63/mmm) in which Ge and Sb disorder over the anion sites, and another that is a new intermetallic compound, Co3Ge2Sb. Single-crystal X-ray diffraction reveals that Co3Ge2Sb crystallizes in the hexagonal space group P6/mmm with a = 8.9128(13) Å, c = 7.6312(8) Å, and Z = 6 (T = 22°C). The structure of Co3Ge2Sb comprises alternating kagomé nets of Co atoms and 63 nets of Ge atoms, with Sb2 pairs stuffed along the centres of the concentric hexagons of these nets. Co3Ge2Sb may be regarded as an intermediate structure that is distorted from the limiting CoSn and CaCu5 structures. Key words: cobalt, germanium, antimony, pnictide, crystal structure

Surface organometallic chemistry — Carbonyl complexes of Re(I) with silanolates as models of silica anchored rhenium carbonyl species

2005 ◽  
Vol 83 (6-7) ◽  
pp. 1017-1024
Author(s):  
Giuseppe D'Alfonso ◽  
Claudia Dragonetti ◽  
Simona Galli ◽  
Elena Lucenti ◽  
Piero Macchi ◽  
...  
Keyword(s):  
Single Crystal ◽  
Organometallic Chemistry ◽  
Key Words ◽  
Molecular Model ◽  
Carbonyl Complexes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rhenium Carbonyl ◽  
Surface Organometallic Chemistry ◽  
Carbonyl Species

Reaction of Me3SiONa with [Re(CO)5Cl] affords the new complex Na[Re2(CO)6(µ-OSiMe3)3], which could be generated via formation of [Re(CO)5OSiMe3] followed by immediate reaction with Me3SiO–. Substitution of some CO ligands by phosphines significantly decreases the electrophilicity of the Re(I) center, and therefore hinders further attack by Me3SiO–. Thus, fac-[Re(CO)3(Ph2PCH2CH2PPh2)OTf] (OTf is the triflate anion) reacts with Me3SiONa to give fac-[Re(CO)3(Ph2PCH2CH2PPh2)OSiMe3], a molecular model of silica anchored [Re(CO)5OSi≡]. However, substitution of only one CO by triphenylphosphine is not enough to avoid the formation of [Re2(CO)6(µ-OSiMe3)3]–. While fac-[Re(CO)3(Ph2PCH2CH2PPh2)OSiMe3] is stable towards hydrolysis, [Re2(CO)6(µ-OSiMe3)3]– is readily hydrolyzed to [Re2(CO)6(µ-OH)(µ-OSiMe3)2]–, a molecular model of silica anchored [Re2(CO)6(µ-OH)(µ-OSi≡)2]–, whose structure has been determined by single crystal X-ray diffraction. Key words: surface organometallic chemistry, rhenium, silica, silanolate, molecular model.

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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