Atropodiastereoisomerism and pseudoassymetry with axial chirality of ligands in bis(2-methyl-1-naphthyl)methanols

1979 ◽  
Vol 44 (10) ◽  
pp. 2946-2969 ◽  
Author(s):  
Otakar Červinka ◽  
Karel Bláha ◽  
Anna Fábryová ◽  
R. Fink ◽  
Dick Van der Helm ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
Lithium Aluminium Hydride ◽  
X Ray Diffraction ◽  
X Ray ◽  
Axial Chirality ◽  
H Nmr ◽  
Lithium Aluminium

On reduction of bis(2-methyl-1-naphthyl) ketone (I) with lithium aluminium hydride alcohol VI was formed which isomerized into alcohol VII. Both alcohols, the configuration of which were proved using 1H-NMR spectra and X-ray diffraction, represent the first example of compounds having a centrum of pseudoassymetry and axial chirality of ligands.

Preparation, properties and structure of some intermediate nido- and arachno-monocarbaboranes

1981 ◽  
Vol 46 (10) ◽  
pp. 2345-2353 ◽  
Author(s):  
Karel Baše ◽  
Bohumil Štíbr ◽  
Jiří Dolanský ◽  
Josef Duben
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Nmr Spectra ◽  
Liquid Ammonia ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Starting Compound

The 6-N(CH3)3-6-CB9H11 carbaborane reacts with sodium in liquid ammonia with the formation of 6-CB9H12- which was used as a starting compound for preparing the 4-CB8H14, 9-L-6-CB9H13 (L = (CH3)2S, CH3CN and P(C6H5)3), 1-(η5-C5H5)-1,2-FeCB9H10-, and 2,3-(η5-C5H5)2-2,31-Co2CB9H10- carboranes. The 4-CB8H14 compound was dehydrogenated at 623 K to give 4-(7)-CB8H12 carborane. Base degradation of 6-N(CH3)3-6-CB9H11 in methanol resulted in the formation of 3,4-μ-N(CH3)3CH-B5H10. The structure of all compounds was proposed on the basis of their 11B and 1H NMR spectra and X-ray diffraction was used in the case of the transition metal complexes.

Organometallic oxides: preparation of the cluster [(η-C5Me5)Mo]4O7 by reduction of [(η-C5Me5)MoCl(O)]2(μ-O) or (η-C5Me5)MoCl2(O)

2000 ◽  
Vol 78 (3) ◽  
pp. 383-394
Author(s):  
Frank Bottomley ◽  
Victor Sanchez ◽  
Robert C Thompson ◽  
Olusola O Womiloju ◽  
Zhiqiang Xu
Keyword(s):  
Nmr Spectra ◽  
Chloroform Solution ◽  
X Ray Diffraction ◽  
Broad Resonance ◽  
Nmr Spectrum ◽  
X Ray ◽  
Temperature Range ◽  
H Nmr ◽  
Tributyltin Hydride ◽  
Effective Moment

Reduction of [(η-C5Me5)MoCl(O)]2(μ-O) or (η-C5Me5)MoCl2(O) with sodium or magnesium amalgam, magnesium turnings, or tributyltin hydride produced [(η-C5Me5)Mo]4O7, with [(η-C5Me5)Mo(O)(μ-O)]2 as a co-product. [(η-C5Me5)Mo]4O7 was characterized by X-ray diffraction, mass spectrometry, 1H NMR and IR spectroscopies, and magnetism. Crystals of [(η-C5Me5)Mo]4O7 contained a tetrahedral [(η-C5Me5)Mo]4 unit (Mo-Mo = 2.909 (3) Å) with the Mo4O7 core having the structure Mo4(μ2-O(b))3(µ2-O(c))3(µ3-O(a)) (3). Microcrystalline samples of [(η-C5Me5)Mo]4O7 were paramagnetic over the temperature range 2-300 K, with an effective moment of 1.26 μB at 300 K. [(η-C5Me5)Mo]4O7 was also paramagnetic in chloroform solution, over the temperature range 223-298 K, with an effective moment of 1.43 µB at 298 K. The 1H NMR spectrum showed a broad resonance at 16.3 ppm (Δν 1/2 = 113 Hz) and two narrow resonances at 1.89 ppm and 1.69 ppm (Δν 1/2 = 5 Hz). The magnetism and NMR spectra showed that [(η-C5Me5)Mo]4O7 existed in two forms which were in equilibrium in solution. One form was paramagnetic (S = 1), with the Mo4O7 core having the geometry 3, and the other was diamagnetic (S = 0), with the Mo4O7 core having the geometry 4.Key words: cluster, cyclopentadienyl, molybdenum, oxide, paramagnetism.

Photoreaktionen von Dekacarbonyldirhenium mit Allen und unverzweigten Allenderivaten / Photoreactions of Decacarbonyldirhenium with Allene and Unbranched Derivatives of Allene

1995 ◽  
Vol 50 (4) ◽  
pp. 649-660 ◽  
Author(s):  
Cornelius G. Kreiter ◽  
Wolfgang Michels ◽  
Gerhard Heeb
Keyword(s):  
Nmr Spectra ◽  
Crystal And Molecular Structure ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Oxidative Rearrangement ◽  
Dirhenium Complexes ◽  
Derivatives Of ◽  
By Products

Decacarbonyldirhenium (1) reacts upon UV irradiation with allene (2), 1,2-butadiene (3) and 2,3-pentadiene (4) preferentially by CO substitution and oxidative rearrangement to the corresponding enneacarbonyl-μ-η1:3-endiyl-dirhenium complexes 5, 9, and 15 and to the octacarbonyl-μ-η2:2-allene-dirhenium complexes 6, the stereoisomers 10, 11, and 16. At elevated temperature 5, 9, and 15 loose CO and yield by a reductive rearrangement also the complexes 6, 10, 11, and 16. In addition to these main products, depending upon the allene derivative used, various by-products are obtained.By-products of the reaction o f 1 with 2 are octacarbonyl-μ-η3:3-(2,3-dimethylene-buta-1,4- diyl)dirhenium (7) and μ-η2:2-allene-hexacarbonyl-μ-η1:3-1-propene-1,3-diyl-dirheniurn (8). The photo reaction of 1 with 3 yields, in addition to 9-11, tetracarbonyl-η3-(E-5-ethylidene- 4-methyl-2-cyclopenten-1-yl)rhenium (12) and tetracarbonyl-η3-(Z-5-ethyliden-4- methyl-2-cyclopenten-1-yl)rhenium (13) as a mixture of isomers. 1 and 4 form the by-products tetracarbonyl-η3-(EZ-3-penten-2-yl)rhenium (17), tetracarbonyl-η3-(EE-3-penten-2-yl)rhenium (18) and heptacarbonyl-μ-η1:2:1:2-(4,5-dimethyl-2,6-octadiene-3,6-diyl)dirhenium (19) with an unusually bridging and chelating ligand. The constitutions of the reaction products have been concluded from the IR and 1H NMR spectra. For 19 the crystal and molecular structure has been determined by X-ray diffraction analysis.

Preparation and Crystal Structure of Genistein Benzenesulfonate Prodrugs

2008 ◽  
Vol 2008 (10) ◽  
pp. 555-558 ◽  
Author(s):  
You Peng ◽  
Zeyuan Deng ◽  
Shaojie Lang ◽  
Yawei Fan
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Sulfonic Acid ◽  
Nmr Spectra ◽  
High Yield ◽  
X Ray Diffraction ◽  
Aromatic Rings ◽  
X Ray ◽  
H Nmr ◽  
Ester Prodrugs

In order to improve bioavailability and anticancer activity of genistein, a series of novel sulfonic acid ester prodrugs of the isoflavone genistein were synthesised in high yield with excellent regioselectivity. Their structures were characterised by IR, MS, elemental analysis and 1H NMR spectra. The crystal structure was examined by X-ray diffraction. X-ray structure determination revealed that all the aromatic rings in the compound are not coplanar. In the crystal structure, molecules are linked through intermolecular C-H···O hydrogen bonds, forming layers parallel to the ab plane.

Potential antidepressants: 2-(Phenylthio)aralkylamines

1989 ◽  
Vol 54 (7) ◽  
pp. 1995-2008 ◽  
Author(s):  
Jiří Jílek ◽  
Jiří Urban ◽  
Petr Taufmann ◽  
Jiří Holubek ◽  
Antonín Dlabač ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
Benzyl Chloride ◽  
Lithium Aluminium Hydride ◽  
Pharmacological Profile ◽  
H Nmr ◽  
Lithium Aluminium ◽  
Alternative Approach ◽  
Phenyl Acetonitrile ◽  
Claisen Reaction ◽  
Pharmacological Testing

Reactions of 2-(phenylthio)benzyl chloride with dimethylamine, diethylamine, pyrrolidine, piperidine, morpholine, and 1-methylpiperazine afforded the title compounds VI-XI. Reaction of 2-(phenylthio)benzaldehyde with nitromethane gave the nitrostyrene XIV which was reduced with lithium aluminium hydride to 2-(2-(phenylthio)phenyl)ethylamine (XVI). This was transformed to the N-methyl and N,N-dimethyl derivatives XVIII and XIX. The Claisen reaction of (2-(phenylthio)phenyl)acetonitrile with ethyl acetate afforded compound XXI which was cleaved by phosphoric acid to (2-(phenylthio)phenyl)acetone (XX). The Leuckart-Wallach reaction afforded the formamide XXIII which was used as starting material for preparing the amines XXIV-XXVI. The alternative approach to these compounds starting by reaction of the aldehyde XII with nitroethane was complicated by the fact that in addition to the nitropropene XV 2-(phenylthio)benzonitrile was also formed. The synthetic use of the inhomogeneous XV resulted then in mixtures of amines XXIV-XXVI with IV-VI which was followed by means of mass and 1H NMR spectra. The amines XXIV-XXVI were oxidized to the sulfoxides XXVII-XXIX. The oily bases were transformed to crystalline salts and spectra of all homogeneous bases were recorded. Pharmacological testing showed the amine VI (VÚFB-15 370) to be a promising potential antidepressant. The amines XI and XXV showed also pharmacological profile of potential antidepressants.

Structure of a pentacyclic triterpenyl angelate from Loeseliamexicana. 1H 2D-NMR data and stereochemistry

1989 ◽  
Vol 67 (12) ◽  
pp. 2071-2077 ◽  
Author(s):  
M. Jiménez E. ◽  
K. Velézquez ◽  
A. Lira-Rocha ◽  
A. Ortega ◽  
E. Díaz ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
Parent Compound ◽  
2D Nmr ◽  
X Ray Diffraction ◽  
Pentacyclic Triterpene ◽  
Nmr Structure Determination ◽  
X Ray ◽  
H Nmr ◽  
Nmr Data ◽  
Unambiguous Assignment

The total assignment of 1H NMR spectra of a pentacyclic triterpene from Loeseliamexicana was performed using selected 2D-NMR experiments (COSY, NOE). X-ray diffraction data were obtained from the parent compound as supplemental information to the NMR investigations. The data allowed for the unambiguous assignment of the structure and the stereochemistry of the title compound. Keywords: pentacyclic triterpene NMR, 2D NMR of terpenes, X-ray of triterpenes, triterpenyl angelate NMR, X-ray -2D NMR structure determination.

Degradation-insertion reactions of decaborane(14) with inorganic salts

1983 ◽  
Vol 48 (9) ◽  
pp. 2593-2603 ◽  
Author(s):  
Karel Baše
Keyword(s):  
Diffraction Analysis ◽  
Nmr Spectra ◽  
Inorganic Salts ◽  
Analogous Reaction ◽  
X Ray Diffraction ◽  
Insertion Reactions ◽  
X Ray ◽  
Lewis Bases ◽  
H Nmr

Decaborane(14) reacts with NaNO2 in tetrahydrofuran forming the [9-tetrahydrofuran-6-NO2B10H12]- salt which after protonization with concentrated H2SO4 or diluted HCl affords azaboranes 6-NB9H12 and 4-NB8H13, respectively. The 6-NB9H12 azaborane is hydrolyzed to the 4-NB8H13 azaborane and reacts with Lewis bases under the formation of the 9-L-6-NB9H12 ligand derivatives (L = (CH)S, CHCN, (CH)P). By the reduction of 9-CHCN-6-NBH with LiAlH4 in tetrahydrofuran the 6-NB9H13- anion was prepared. By an analogous reaction of decaborane(14) with KHSO3 in water and by a subsequent protonization of the formed intermediate with concentrated H2SO4 or diluted HCl the thiaboranes 6-SB9H11 and 4-SB8H12, respectively, were prepared. The reaction of decaborane(14) with Na2SeO3 in tetrahydrofuran followed by the protonization of the intermediate with diluted HCl afforded the 7,8-Se2B9H9 species. Structures of all compounds were proposed on the basis of the 11B and 1H NMR spectra; in the case of 4-NB8H13, the structure was determined by the X-ray diffraction analysis.

Electronic Structure of 2,6-Bis{.N-(2-hydroxyphenyl)immoinethyl}-4-methylphenol

1999 ◽  
Vol 54 (7) ◽  
pp. 929-939 ◽  
Author(s):  
Miki Hasegawa ◽  
Yasunori Yamada ◽  
Ken-ichi Kumagai ◽  
Toshihiko Hoshi
Keyword(s):  
Diffraction Analysis ◽  
Electronic Absorption ◽  
Nmr Spectra ◽  
X Ray Diffraction ◽  
Mo Calculations ◽  
Absorption Bands ◽  
Polar Solvents ◽  
Additional Band ◽  
X Ray ◽  
H Nmr

The electronic and molecular structure of 2,6-bis{N-(2-hydroxyphenyl)iminomethyl}-4- methylphenol (hpimp) is clarified from the measurements of electronic absorption and 1H NMR spectra in various solvents and an X-ray diffraction analysis, together with MO calculations. Electronic absorption bands of hpimp are at 422, 397.9, 359, 341, 294.3, 265.8, and 224 nm in the non-polar solvent cyclohexane. In polar solvents, such as methanol, an additional band which is assigned to a partly formed keto-amine hpimp, is observed at 499 nm. From the 1H NMR spectra it is seen that hpimp exists in the enol-imine form in non-polar solvents, and as an equilibrium mixture of enol-imine and keto-amine forms in polar solvents. Each electronic absorption band of solid hpimp in a KBr disk is broadened compared with the solution state, and an additional band, again assigned to the keto-amine form, appears around 499 nm. An X-ray diffraction analysis shows that hpimp assumes a keto-amine structure in the solid state, and forms a column structure along the c-axis. MO calculations suggest that the enol-imine hpimp has a twist structure around the two C−C single bonds, the twist angle being 100° to 120°.

Synthesis and Crystal Structure of a New Ni2+ Complex1

2012 ◽  
Vol 441 ◽  
pp. 387-391 ◽  
Author(s):  
Yin Zhi Jiang ◽  
Yang Zou ◽  
Lian Qun Zhang
Keyword(s):  
Crystal Structure ◽  
Nmr Spectra ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
H Nmr ◽  
Coordination Sites ◽  
Assisted Decomposition ◽  
Coordination Reaction

(S,S)-N,N’- bi-(benzal)-1,2-cyclohexanediamine Schiff base (1) was synthesized and characterized by 1 H NMR spectra, MS spectra and IR spectra. And the coordination reaction of 1 with chlorate of Ni(II) was studied. The reaction of 1 with NiII salt [NiCl2] generates a new compound (2). 2 was characterized using IR spectroscopy, elemental analysis and single-crystal X-ray diffraction. Crystal data for 2: space group Coca, with a = 24.580(4)Å, b = 9.5829(13)Å, c = 7.6836(11)Å, α=90.00º, β=90.00º, γ=90.00º, Z=4, V= 1809.8(5)Å3, Dc=1.446 mg.m-3, µ=1.376 mm-1, F(000)=840. There are 6 coordination sites around Ni2+ of 2, which are respectively occupied by two oxygen atoms (all from two H2O molecules) and four nitrogen atoms [all from two 1,2-cyclohexanediamine molecule]. The Ni atom and four chelating nitrogen atoms are coplanar. There exist intra-molecular H-bond and intermolecular H-bond. The mechanism of metal-assisted decomposition of 1 was also discussed briefly.

Syntheses and some chemistry of stable isoporphyrin systems

2002 ◽  
Vol 06 (10) ◽  
pp. 607-616 ◽  
Author(s):  
Hong Xie ◽  
Sam H. Leung ◽  
Kevin M. Smith
Keyword(s):  
Nmr Spectra ◽  
Optical Spectra ◽  
Metal Salts ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metal Free ◽  
H Nmr ◽  
Ring Synthesis

Isoporphyrin zinc(II) complexes can be synthesized using the MacDonald ["2+2"] approach, with suitably substituted dipyrromethanes and 5,5-dialkyldipyrromethanes. The zinc(II) complexes are stable, show characteristic optical and 1 H NMR spectra, and have been characterized as perchlorate salts by X-ray diffraction. Attempts to prepare other metal salts of isoporphyrins ( Ni , Cu , Fe ), either by metalation during ring synthesis or by subsequent metalation of metal-free isoporphyrins, were unsuccessful. Evidence shows that a metal-free isoporphyrins can synthesized by demetalating the corresponding zinc(II) complexes with TFA. However, workup with base after the reaction must be avoided. The optical spectra of relatively unstable metal-free isoporphyrins (λ max ( CH 2 Cl 2) 430, 700 nm) are blue shifted relative to their zinc(II) complexes (λ max ( CH 2 Cl 2) 416, 731, 797 nm), and can be remetalated with zinc(II) acetate, to generate the fully characterized zinc(II) salts.

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