Revision of nido-2,6-C2B7H11 to the arachno-4,5-C2B7H13 structure. Determination of the structure from NMR spectra and chemical origin

1988 ◽  
Vol 53 (11) ◽  
pp. 2742-2752 ◽  
Author(s):  
Stanislav Heřmánek ◽  
Tomáš Jelínek ◽  
Jaromír Plešek ◽  
Bohumil Štíbr ◽  
Jiří Fusek
Keyword(s):  
Structure Determination ◽  
Nmr Spectra ◽  
Open Face ◽  
C Nmr

The assymetric C2B7 carborane held until the present for 2,6-C2B7H11, is in reality the arachno-4,5-C2B7H13 carborane (I) with two adjacent B-H-B bridges, one BH2, one CH2 and one CH group in the hexagonal open-face. The arrangement of the boron network was determined on the basis of the 11B, 11B-11B COSY, 1H and 13C NMR spectra and on the T1(B) study. The connection of B- with C-skeletal atoms was deduced from the positions of deuterium in the deutero analogs prepared by the CH2O/D3O+ degradation of three selectively deuterated nido-[7,8-C2B9H12]- anions. A selective transmission of D from CD2O to the B(9) vertex in the course of the CD2O/D3O+ degradation was observed. The structure of arachno-4,5-C2B7H13 is consistent with the different pathways of its preparation.

NMR Determination of the Structure of Peracetylated Icariside B2 from Veratrum Lobelianum BERNH.

1995 ◽  
Vol 60 (8) ◽  
pp. 1380-1385 ◽  
Author(s):  
Václav Suchý ◽  
Miloš Buděšínský ◽  
Karel Ubik ◽  
Daniel Grančai ◽  
Vlasta Földešiová
Keyword(s):  
Detailed Analysis ◽  
Nmr Spectra ◽  
Aerial Part ◽  
C Nmr

rel(1S,4S,5R)-3,3,5-Trimethyl-4-[( 1E)-3-oxo-1-butenyl]-4,5-epoxy-cyclohexyl-O-β-D-glucopyranoside (I) was isolated from the aerial part of Veratrum lobelianum BERNH. The structure was derived mainly from detailed analysis of 1H and 13C NMR spectra of its acetylated derivative II. Compound I has been already reported under the name icariside B2in Epimedium grandiflorum MORR. var. thunbergianum (MIQ.) NAKAI.

Direct and indirect recording of tungsten-183 NMR spectra, and structure determination of (diene)3M (M = tungsten, molybdenum) compounds in solution

1987 ◽  
Vol 6 (5) ◽  
pp. 938-942 ◽  
Author(s):  
Reinhard. Benn ◽  
Christian. Brevard ◽  
Anna. Rufinska ◽  
Gerhard. Schroth
Keyword(s):  
Structure Determination ◽  
Nmr Spectra

scholarly journals Darstellung und Charakterisiening der Spezies R-C7H7Mo(CO)3 und die Röntgenstrukturanalyse von / Synthesis and Characterisation of the Species R-C7H7Mo(CO)3 and the X-ray Structure Determination of

1978 ◽  
Vol 33 (4) ◽  
pp. 361-365 ◽  
Author(s):  
Margret Sommer ◽  
Klaus Weidenhammer ◽  
Henning Wienand ◽  
Manfred L. Ziegler
Keyword(s):  
Carbon Atom ◽  
Structure Determination ◽  
Nmr Spectra ◽  
X Ray ◽  
Ethyl Group ◽  
H Nmr

The species R−C7H7Mo(CO)3 (R=−CH2COCH3,−CH(CH3)COCH3,−CH(CH)(CH3)2COCH3) have been synthesized by electrolysing [η7-C7H7Mo(CO)3]+, η7-C7H7Mo(CO)2Br and the dimers [C7H7Mo(CO)3]2 and (C7H7)2Mo(CO)3, respectively, in suitable ketones and HBr. 1H NMR spectra and the X-ray structure determination of (CH3−CO−CH(CH3)−C7H7)Mo(CO)3 revealed the CH3−CO−CH(CH3)-group being bonded to the cycloheptatriene ligand via the α-carbon atom of the ethyl group.

Simple NMR Determination of 5α/5β Configuration of 3-Oxosteroids

2001 ◽  
Vol 66 (10) ◽  
pp. 1529-1544 ◽  
Author(s):  
Hana Chodounská ◽  
Miloš Buděšínský ◽  
Romana Šídová ◽  
Miroslav Šíša ◽  
Alexander Kasal ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
Low Frequency ◽  
Simple Method ◽  
H Nmr ◽  
Steroid Skeleton ◽  
C Nmr

A simple method to distinguish the 5α- from the 5β-isomers of 3-oxosteroids based on low-frequency 1H NMR spectra was proposed. Additional 1H and 13C NMR characteristics were derived from the comparison of completely assigned spectra of the 5α- and 5β-isomers. The effect of substitution at different positions of steroid skeleton was evaluated on a series of isomeric 3-oxosteroids, prepared for this purpose.

scholarly journals Computational simulations of solid state NMR spectra: a new era in structure determination of oxide glasses

RSC Advances ◽  
2013 ◽  
Vol 3 (27) ◽  
pp. 10550 ◽  
Author(s):  
Thibault Charpentier ◽  
Maria Cristina Menziani ◽  
Alfonso Pedone
Keyword(s):  
Solid State ◽  
Structure Determination ◽  
Solid State Nmr ◽  
Nmr Spectra ◽  
Oxide Glasses ◽  
Computational Simulations ◽  
New Era

The determination of the stereochemistry of epoxides located at the 5,6-positions of decalinic systems: An empirical method based on 13C NMR chemical shifts

2002 ◽  
Vol 80 (7) ◽  
pp. 774-778 ◽  
Author(s):  
Raquel M Cravero ◽  
Guillermo R Labadie ◽  
Manuel González Sierra
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Empirical Method ◽  
Nmr Chemical Shifts ◽  
13C Nmr Chemical Shifts ◽  
Empirical Rule ◽  
C Nmr

The 13C NMR spectra of a series of 5,6-epoxides in decalinic systems were studied. The interpretation of the chemical shifts allowed us to formulate an empirical rule to predict the epoxide stereochemistry. A discussion of the scope and limitations of this method and its extension to larger carbon skeletons is also presented.Key words: epoxide stereochemistry, 13C NMR, NMR, decalinic systems, oxiranes.

Strukturbestimmung von Ga[GaCl4] und α-Ga[GaBr4] nach Kristallisation aus Halogenbenzolen / Structure Determination of Ga[GaCl4] and α-Ga[GaBr4] Crystallized from Halobenzene Solvents

1987 ◽  
Vol 42 (5) ◽  
pp. 553-556 ◽  
Author(s):  
H. Schmidbaur ◽  
R. Nowak ◽  
W. Bublak ◽  
P. Burkert ◽  
B. Huber ◽  
...  
Keyword(s):  
Single Crystals ◽  
Crystal Structures ◽  
Structure Determination ◽  
Nmr Spectra ◽  
Approximate Calculation ◽  
Crystal Data ◽  
Crystalline Powder ◽  
Powder Samples ◽  
Asymmetry Parameters

Single crystals of Ga[GaCl4] and α-Ga[GaBr4] have been obtained by crystallization from chlorobenzene and bromobenzene, respectively. The crystal structures of the two compounds, determined previously only on the basis of photographic data, were refined to a more satisfactory level of accuracy. The results confirm the presence of tetrahedral GaX4- anions as thecounterions to dodecahedrally coordinated Ga+ cations. The gallium-halogen distances in these dodecahedral arrays fall into four classes, thus resulting in a significant asymmetry of the Ga(I) center. This deviation from ideal S4 symmetry is also apparent in the 69Ga NMR spectra of the crystalline powder samples. Approximate calculation of the data leads to asymmetry parameters (η) of 0.44 and 0.27 for the chloride and bromide, respectively. Crystal data Ga[GaCl4]: Pnna (#52), a = 7.200(1), b = 9.625(1), c = 9.498(1) Å; Z = 4. For α-Ga[GaBr4]: Pnna, a = 7.528(1), b = 9.972(1), c = 10.010(1) Å, Z = 4.

scholarly journals Isolation and Structure Determination of Banana Pseudostem Based Uro-Lignin

1970 ◽  
Vol 33 (2) ◽  
pp. 227-229
Author(s):  
Md Abdul Hye
Keyword(s):  
Molecular Structure ◽  
Structure Determination ◽  
Nmr Spectra ◽  
Naoh Solution ◽  
Academy Of Sciences

Lignin was isolated from wet Banana pseudostem with 2% NaOH solution by boiling. The isolated lignin was treated with urea and called uro-lignin. IR, Mass and NMR spectra of urolignin were taken to determine its molecular structure. DOI: 10.3329/jbas.v33i2.4106 Journal of Bangladesh Academy of Sciences, Vol. 33, No. 2, 227-229, 2009

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