13C-NMR-Untersuchiingen an einigen Organosilanen /13 C NMR Studies on Some Organosilanes

1979 ◽  
Vol 34 (9) ◽  
pp. 1270-1274 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Werner Biffar
Keyword(s):  
13C Nmr ◽  
Structural Features ◽  
Coupling Constants ◽  
Coupling Mechanism ◽  
Nmr Studies ◽  
Nmr Parameters ◽  
Nmr Data ◽  
Fermi Contact ◽  
Fermi Contact Term ◽  
C Nmr

Abstract13C-NMR data (δ13C, J(13C1H), J(13C13C), J(29Si13C)) of noncyclic organosilanes CH4-n[Si(CH3)3]n (n = 1-4), (CH3)4-nC[Si(CH3)3]n (n = 1, 3, 4) and cyclic organosilanes [(CH3)2SiCH2]n (n = 2, 3), (CH3)2Si(CH2)3 are reported. Comparison of reduced coupling constants 1K proves the Fermi-contact-term to be the dominant coupling mechanism. Structural features of the four-membered heterocycles become apparent by comparison of their 13C NMR parameters with those of corresponding cycloalkanes, noncyclic organo­silanes and the 1,3,5-trisilacyclohexane derivative.

10B-, 11B-, 13C-NMR-Untersuchungen von closo-Pentaalkyl-1.5-dicarbapentaboranen(5) / 10B-, 11B-, 13C NMR Studies of closo-Pentaalkyl-1,5-dicarbapentaboranes(5)

1981 ◽  
Vol 36 (6) ◽  
pp. 704-707 ◽  
Author(s):  
Roland Köster ◽  
Bernd Wrackmeyer
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Chemical Shifts ◽  
Parent Compound ◽  
Coupling Constants ◽  
Mo Calculations ◽  
Nmr Studies ◽  
Nmr Parameters ◽  
Alkyl Substitution ◽  
C Nmr

AbstractNMR parameters [chemical] shifts (δ11B, δ13C) and coupling constants (1J(13C1H), 1J(13C11B), 1J(13C13C), 1J(11B11B) of closo-pentaalkyl-1,5-dicarbapentaboranes(5) were determinated by 10B, 11B, and 13C NMR spectroscopy. The magnitudes of 1J(13C11B) and 1J(13C13C) correspond to 1J(11B1H), 1J(13C11B) and 1J(13C1H) in the parent compound 1,5-C2B3H5 . According to predictions from MO calculations 1J(11B11B) was found to be < 10 Hz. Together with these data the δ11B and δ13C values show that neither the structure nor the bonding situation in the polyhedron are significantly affected by alkyl substitution.

scholarly journals Structural Investigations of C-Nitrosobenzenes. Part 3.1 Solid-state and Solution 13C NMR Studies, and Crystal Structure of E-(4-CIC6H4NO)2

1999 ◽  
Vol 23 (3) ◽  
pp. 202-203
Author(s):  
Daniel A. Fletcher ◽  
Brian G. Gowenlock ◽  
Keith G. Orrell ◽  
David C. Apperley ◽  
Michael B. Hursthouse ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
13C Nmr ◽  
Nmr Studies ◽  
Structural Investigations ◽  
Nmr Data ◽  
C Nmr

Solid-state and solution 13C NMR data for the monomers and dimers of 3- and 4-substituted nitrosobenzenes, and the crystal structure of E-(4-CIC6H4NO)2 are reported.

Bonding in Cyclobutabenzene Chromium Tricarbonyl Complexes Studied by 13C NMR. Evidence of π-Bond Localization from 1J(13C,13C)

1995 ◽  
Vol 50 (4) ◽  
pp. 483-487 ◽  
Author(s):  
H. Butenschön ◽  
B. Gabor ◽  
R. Mynott ◽  
H. G. Wey
Keyword(s):  
13C Nmr ◽  
Coupling Constants ◽  
Chromium Tricarbonyl ◽  
Chromium Complex ◽  
Nmr Parameters ◽  
Chromium Tricarbonyl Complexes ◽  
The One ◽  
Bond Localization ◽  
Insight Into ◽  
C Nmr

The 13C NMR parameters of several cyclobutabenzenes ( 1a - 1e ) and their corresponding complexes (cyclobutabenzene)M(CO)3 (M = Cr, Mo, W, 2 - 4 ) are presented and discussed. Two cyclobutabenzenes 1b and 1d and their chromium tricarbonyl complexes 2b and 2d have been examined in greater detail: the signal assignments have been confirmed by 2 D-INADEQUATE and the one bond coupling constants 1J(13C ,13C) measured at natural abundance using 1 D-INADEQUATE . Although the results provide no insight into why the chromium complex of 1,2 - dioxocyclobutabenzene (1e) is much more reactive at the keto groups than 1e itself, they do reveal a weak but not negligible alternation of the carbon s-character in the C - C bonds of the 6-membered rings both in the free cyclobutabenzenes and in the complexes, thus providing evidence for slight bond fixation (Mills-Nixon effect).

scholarly journals 13C NMR of the Tetrakis(phenylethynyl)borate Anion and of Some Phenylethynyl Boranes

1982 ◽  
Vol 37 (6) ◽  
pp. 788-789 ◽  
Author(s):  
Bernd Wrackmeyer
Keyword(s):  
13C Nmr ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Triple Resonance ◽  
Triple Resonance Experiments ◽  
Nmr Parameters ◽  
C Nmr

Abstract The 13C NMR parameters of the title compounds are assigned by heteronuclear triple resonance experiments 13C{1H,11B}. The magnitude of the coupling constants J(13C11B) corresponds roughly with J(13C13C). The chemical shifts δ13C reveal B-C(pp) π bonding which is, however, rather weak when compared with C+-C(pp) π bonding in phenylethynyl carbocations.

11B- und 13C-NMR-Spektroskopie von nido-Hexaalkyl-2.3.4.5-tetracarbahexaboranen(6) / 11B- und 13C-NMR Spectroscopy of nido-Hexaalkyl-2,3,4,5-tetracarbahexaboranes(6)

1982 ◽  
Vol 37 (4) ◽  
pp. 412-419 ◽  
Author(s):  
Bernd Wrackmeyer
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
13C Nmr Spectroscopy ◽  
Coupling Constants ◽  
Triple Resonance ◽  
Triple Resonance Experiments ◽  
Nmr Data ◽  
Nuclear Shielding ◽  
C Nmr

11B and 13C NMR data of peralkylated nido-2,3,4,5-tetracarbahexaboranes(6) are reported. Application of selective heteronuclear triple resonance experiments 13C{1H,11B} enables to assign the structures of various isomers. The magnitude of the coupling constants 1J(11B11B), 1J(13C11B) and 1J(13C13C) is in accord with expectations based on the conception of bonding in carboranes. The comparison of δ11B and δ13C data of the nido- 2,3,4,5-tetracarboranes(6) with δ13C-data of corresponding non-classical carbocations shows the influence of charge upon the nuclear shielding of carbon in the latter.

13C NMR spectra of sodium naphthalenesulphonates

1985 ◽  
Vol 50 (8) ◽  
pp. 1852-1861 ◽  
Author(s):  
Dobroslav Šnobl ◽  
Antonín Lyčka ◽  
Jaroslav Horyna
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Deuterium Oxide ◽  
Coupling Constants ◽  
13C Nmr Spectra ◽  
Nmr Parameters ◽  
Measured Effect ◽  
C Nmr

13C NMR spectra of thirteen sodium naphthalenesulphonates have been measured in deuterium oxide. The 13C chemical shifts have been assigned, and the nJ(13CH) coupling constants have been measured. Effect of SO3(-) group on the 13C NMR parameters is discussed.

Solid state stereochemistry of crown ethers: X-ray crystal structure and 13C NMR studies of the LiNCS complex of 1,4,7,11-tetraoxacyclotetradecane

2000 ◽  
Vol 78 (3) ◽  
pp. 316-321
Author(s):  
G W Buchanan ◽  
A B Driega ◽  
G PA Yap
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Crown Ether ◽  
13C Nmr ◽  
Title Complex ◽  
Nmr Studies ◽  
Nmr Spectrum ◽  
X Ray ◽  
Large Amplitude Motion ◽  
C Nmr

The title complex is asymmetric in the crystal due to the spatial orientation of the NCS function. The space group has been determined to be P21 with a = 9.496(3), b = 8.736(3), c = 9.676(3) Å, β = 117.859(5)°, and Z = 2. The solid state 13C NMR spectrum is consistent with the lack of symmetry in the crystal and there is little evidence for large amplitude motion in the macrocycle as determined from the dipolar dephased spectrum.Key words: macrocyclic crown ether, lithium complex.

NMR-spektroskopische Untersuchungen an 1,1-Thiophendioxid und verwandten Verbindungen / NMR Spectroscopical Investigations of Thiophene 1,1-Dioxide and Related Compounds

1984 ◽  
Vol 39 (7) ◽  
pp. 915-920 ◽  
Author(s):  
Herbert Meier ◽  
Thomas Molz ◽  
Heinz Kolshorn
Keyword(s):  
Computer Simulation ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Multiple Resonance ◽  
Nmr Data ◽  
Cyclic Diene ◽  
Related Compounds ◽  
C Nmr

The 1H and 13C NMR data of thiophene 1,1-dioxide (3) and related compounds, especially of the precursor 2 and the consecutive product 5 are evaluated by computer simulation and multiple resonance. Chemical shifts and coupling constants reveal that 3 has the character of a cyclic diene. Diatropic or paratropic effects can be excluded.

scholarly journals The NMR Spin Systems of Scutellaria 8β,13-Epoxy-neo-clerod-3-en-15,16-olides and Revision of 1H and 13C NMR Spectra Reported Data

2020 ◽  
Vol 15 (10) ◽  
pp. 1934578X2093378
Author(s):  
Josep Coll Toledano
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Spin Systems ◽  
13C Nmr Spectra ◽  
1H And 13C Nmr ◽  
Nmr Data ◽  
Reported Data ◽  
New Compounds ◽  
C Nmr ◽  
Shielding Effects

The present review of NMR spectroscopic structural elucidation data of new compounds isolated from Scutellaria species is focused on the title compounds, displaying a peculiar 13-spiro feature. It contains a compilation of 1H and 13C NMR data of these diterpenoids grouped by similar substitution patterns. Comparing shielding effects pointed out not only the identity of some compounds (already reported) but also potential misassignments and convenient revisions to get unambiguous structural proposals.

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