Schwefeldiimid, S(NH)2, und monosubstituierte Schwefeldiimide, S(NR)(NH), mit R = tert-Butyl und Trimethylsilyl / Sulfur Diimide, S(NH)2, and Monosubstituted Sulfur Diimides, S(NR)(NH), with R = tert-Butyl and Trimethylsilyl

1985 ◽  
Vol 40 (10) ◽  
pp. 1229-1232 ◽  
Author(s):  
Max Herberhold ◽  
Wolfgang Jellen ◽  
Wolfgang Bühlmeyer ◽  
Wolfgang Ehrenreich ◽  
Josef Reiner
Keyword(s):  
Acetic Acid ◽  
Nmr Spectra ◽  
Parent Compound ◽  
Temperature Dependent ◽  
Tert Butyl ◽  
H Nmr

The unstable parent compound of the sulfur diimides, S(NH)2 (1), has been obtained in solution by stoichiometric protonation of the anion SN22- in K2SN2 with acetic acid. An analogous protonation of the salts S(NR)(NK) leads to the m onosubstituted sulfur diimides S(NR)(NH) containing bulky substituents such as R = tert-butyl (2) and R = trimethylsilyl (3); 2 and 3 can be isolated as white solids below -40 °C. The temperature-dependent 1H NMR spectra of 1-3 indicate the presence of two isomers in solution (ratio 4:1) which are reversible interconverted.

Rotationsbarriere der Endgruppen bei Poly- methinoxonolen verschiedener Kettenlänge / Rotation Barrier of the End Groups of Polymethine Oxonols with Different Chain Lengths

1976 ◽  
Vol 31 (8) ◽  
pp. 1017-1018 ◽  
Author(s):  
H. Oehling ◽  
F. Baer
Keyword(s):  
Nmr Spectra ◽  
Rotation Barrier ◽  
Free Enthalpy ◽  
Temperature Dependent ◽  
Restricted Rotation ◽  
H Nmr ◽  
Enthalpy Of Activation ◽  
End Groups ◽  
Electron Contribution ◽  
Chain Lengths

Abstract Polymethine oxonols show temperature dependent 1H-NMR-spectra because of restricted rotation of the end groups. The dependence of the value of the corresponding free enthalpy of activation AGt on the length of the poly-methine chain can be explained by the change of the π-electron contribution to ⊿G≠.

scholarly journals New Synthetic Routes for 1-Benzyl-1,4,7,10-tetraazacyclododecane and 1,4,7,10-Tetraazacyclododecane-1-acetic Acid Ethyl Ester, Important Starting Materials for Metal-coded DOTA-Based Affinity Tags

2007 ◽  
Vol 62 (3) ◽  
pp. 397-406 ◽  
Author(s):  
Stephan W. Kohl ◽  
Katharina Kuse ◽  
Markus Hummert ◽  
Herbert Schumann ◽  
Clemens Mügge ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Ethyl Ester ◽  
Nmr Spectra ◽  
Acid Ethyl Ester ◽  
Affinity Tags ◽  
X Ray ◽  
H Nmr ◽  
Synthetic Routes ◽  
New Compounds ◽  
C Nmr

Two improved routes to synthesize 1-benzyl-1,4,7,10-tetraazacyclododecane (6) and 1,4,7,10- tetraazacyclododecane-1-acetic acid ethyl ester (11) are described as well as the synthesis of 1-{2-[4-(maleimido-N-propylacetamidobutyl)amino]-2-oxoethyl}-1,4,7,10-tetraazacyclododecane- 4,7,10-triacetic acid (17) and its Y, Ho, Tm, and Lu complexes. The 1H and 13C NMR spectra of the new compounds as well as the single crystal X-ray structure analyses of the intermediates 4-benzyl-1,7-bis(p-toluenesulfonyl)diethylenetriamine (3) and 1,4,7-tris(p-toluenesulfonyl)diethylenetriamine (7) are reported and discussed. The rare earth complexes of 17 have been characterized by 1H NMR spectroscopy and MALDI-TOF mass spectrometry.

Chlormethylchlorphosphane mit sperrigen Substituenten -Synthese und reduktive Enthalogenierung mit Fe2(CO)9 / Bulky Chloromethylchlorophosphines -Syntheses and Reductive Dehalogenation with Fe2 (CO)9

1997 ◽  
Vol 52 (8) ◽  
pp. 883-894 ◽  
Author(s):  
Jörg Fischer ◽  
Peter Machnitzki ◽  
Othmar Stelzer
Keyword(s):  
Nmr Spectra ◽  
Elevated Temperatures ◽  
Reductive Dehalogenation ◽  
Molar Ratio ◽  
Carbonyl Complex ◽  
Temperature Dependent ◽  
Phenyl Derivative ◽  
H Nmr ◽  
Halogen Exchange ◽  
Stage Synthesis

Chloromethylchlorophosphines R(Cl)P-CH2-Cl (R = C6H11, sec-C4H9, 2,4,6-R′3C6H2; R′ = tBu, iPr) with bulky substituents (1a - 1d) have been prepared by treatment of Cl2P-CH2-Cl with organolithium compounds RLi (R = 2,4,6-R′3C6H2) or Grignard reagents RMgX (R = C6H11, sec-C4H9). For the less bulky phenyl derivative Ph(Cl)P-CH2-Cl (1i) a protected group two stage synthesis has been developed employing Et2N(Cl)P-CH2-Cl as an intermediate. Si-N cleavage reactions between Cl2P-CH2-Cl and R2N-SiMe3 or nucleophilic substitution with Ph2NH yield the amino derivatives R′2N(Cl)P-CH2-Cl (R′ = Ph, Et, iPr) (1e, 1g, 1h). The chloromethylbromophosphines R(Br)P-CH2-Cl (R = Br, C6H11) have been obtained by halogen exchange in 1 and 1a with MgBr2 etherate. 1a, 1e, 1g and 1h exist preferably in an antiperiplanar conformation with respect to the P-C(H2) bond as inferred from the analysis of the 1H(CH2)-NMR spectra. Temperature dependent 1H and 13C {1H} NMR spectra indicate restricted rotational processes in 1h. On reaction of 2a with Fe2(CO)9 the η2,μ3-phosphaalkene cluster 3 is obtained, while with 2b (R = 2,4,6-iPr3C6H2) the μ3-phosphinidene cluster 4 is formed. Reductive dehalogenation of 1c (R = 2,4,6-tBu3C6H2) affords the phosphaalkene complex 6 in addition to the 2,3-dihydrobenzo[b]phosphole complex 5. Treatment of the iron carbonyl complex 7c with Fe2(CO)9 in a 1:1 molar ratio at elevated temperatures leads to a novel μ2-phosphido complex 7b with an ortho-metallated Ph2N substituent.

Zum ambidenten Charakter des Cyanotrihydroborat-Liganden in Uran(IV)-Organylen / On the Ambident Nature of the Cyanotrihydroborate Ligand in Organouranium(IV) Complexes

1983 ◽  
Vol 38 (11) ◽  
pp. 1369-1374 ◽  
Author(s):  
R. Dieter Fischer ◽  
Kenan Yünlü
Keyword(s):  
Solid State ◽  
Nmr Spectra ◽  
Colour Change ◽  
Metal Coordination ◽  
Temperature Dependent ◽  
H Nmr ◽  
Trigonal Bipyramidal ◽  
Oligomeric Complex

Both the acceptedly oligomeric complex [(C5H5)3U(μ-NCBH3)]n (1) and its hitherto unknown, appreciably more soluble and volatile homologue, [(CH3C5H4)3U(μ-NCBH3)]n (2), display NIR/VIS spectra typical of trigonal bipyramidal (tbp) metal coordination in the solid state, but of pseudotetrahedral (ψ-Td) coordination e.g. in CH2CI2 and C6H5CH3 solution. The 1H NMR spectra of 2 in these non coordinating solvents can be best explained in terms of temperature dependent equilibria involving the two rapidly interconverting ψ-Td-isomers (CH3C5H4)3U(η3-H3BCN) and (CH3C5H4)3UNCBH3. A reversible colour change: green ⇋ brown at 130-150 °C also suggests the facile rupture of U-H and U-N bonds, respectively, in thermally excited, polycrystalline (2).

scholarly journals Stickstoffverbindungen von Elementen der dritten Hauptgruppe mit intra- und intermolekularen Donor-Akzeptor-Bindungen, V [1]. Spezielle Gallium- und Indiumamide mit Alkoxogruppen / Nitrogen Compounds of Elements of the Third Main Group with Intra- and Intermolecular Donor Acceptor Bonds, V [1]. Special Gallium and Indium Amides with Alkoxo Groups

1988 ◽  
Vol 43 (5) ◽  
pp. 505-512 ◽  
Author(s):  
M. Veith ◽  
J. Pöhlmann
Keyword(s):  
Metal Atom ◽  
Nmr Spectra ◽  
Main Group ◽  
Nitrogen Compounds ◽  
Temperature Dependent ◽  
H Nmr ◽  
The Third ◽  
Donor Acceptor ◽  
Molecular Compounds ◽  
Chelating Effect

AbstractThe lithium alkoxoamidosilane (Me2Si(OtBu)(NtBu)Li)2 (4) and its trimethyltin derivative Me2Si(OtBu)(NtBu)SnMe3 (7) have been used, to introduce the ligand Me2Si(OtBu)(NtBu) = L into molecular compounds of gallium and indium. The following molecules were synthesized: L-M(Me)Cl (M = Ga (5), In (6)), L-InMe2 (8), L-InX2 (X = Cl (9), Br (10)), L2InX (X = Cl (11), Br (12)) and L2Ga2Cl2 (22). The ligand L is assumed to chelate the metal atom on the basis of temperature dependent 1H NMR spectra. The chelating effect is more pronounced in the gallium derivatives than in the indium analogues. Equilibria between L2InX/InX3 and LInX2 have been observed in diethylether solutions. No metal(I) derivatives LGa or LIn could be isolated. L2Ga2Cl2 (22), formally containing gallium(ll), can be sublimed without decomposition at 110 °C in vacuo.

Aliphatic diazo compounds. XIV. The synthesis of 7-substituted 3-diazo-2-norbornanones and the infrared and proton and carbon-13 nuclear magnetic resonance spectra of these diazo ketones and their precursors

1984 ◽  
Vol 62 (9) ◽  
pp. 1751-1766 ◽  
Author(s):  
Peter Yates ◽  
John David Kronis
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Nmr Spectra ◽  
Diazo Compounds ◽  
Lower Field ◽  
Tert Butyl ◽  
H Nmr ◽  
Nuclear Magnetic Resonance Spectra ◽  
C Nmr ◽  
Shielding Effects

syn- and anti-7-Isopropyl-2-norbornanone (5 and 6) were prepared by catalytic hydrogenation of 7-isopropylidene-2-norbornanone; syn- and anti-7-benzhydryl-2-norbornane (9 and 10) were prepared in analogous fashion. Ketones 5 and 6 and syn- and anti-7-tert-butyl-2-norbornanone (7 and 8) were converted to the corresponding 3-diazo-2-norbornanones 1–4 via the monotosylhydrazones 44–47 of the corresponding α-diketones 40–43. The 1H and 13C nmr spectra of 1–10, 40–47, and their precursors have been analyzed. The 1H nmr spectra of the diazo ketones 1–4 have their C-1 and C-4 bridgehead proton signals shifted to higher and lower field, respectively, relative to the bridgehead signals of the corresponding diketones. The 13C nmr spectra of all pairs of bicyclic epimers shown γ-gauche shielding effects by the 7-substituent at (sp3) C-3 in the syn compounds and at C-5 and C-6 in the anti compounds. A converse effect is found at (sp2) C-2 (and C-3 in the diketones). Comparison of the magnitude of the shielding effects of C-7 methyl, isopropyl, benzhydryl, and tert-butyl substituents gives evidence of δ deshielding effects at C-3 in the syn compounds and at C-5 and C-6 in the anti compounds by methyl substituents on C-8.

5J(CH3,SH) as a negative proximate or as a positive σ−π coupling in 2-methylthiophenol derivatives

1985 ◽  
Vol 63 (8) ◽  
pp. 2217-2220 ◽  
Author(s):  
Ted Schaefer ◽  
James Peeling ◽  
Rudy Sebastian ◽  
James D. Baleja
Keyword(s):  
Nmr Spectra ◽  
Sulfhydryl Group ◽  
The Other ◽  
Coupling Mechanism ◽  
Methyl Group ◽  
Tert Butyl ◽  
H Nmr ◽  
Out Of Plane ◽  
Negative Coupling

Analyses of the 1H nmr spectra of 6-chloro-2-methylthiophenol and of 4-tert-butyl-2-methylthiophenol in CCl4 solution, together with double irradiation experiments, show that 5J(CH5,SH) in the former compound is −0.66 Hz and is +0.47 Hz in the latter. In the chloro compound, the sulfhydryl group spends relatively little time in out-of-plane conformations at 300 K. The negative coupling is a consequence of a through-space or proximate coupling mechanism. In the other compound, the sulfhydryl group samples many out-of-plane conformations but relatively few in which the S—H bond lies near the methyl group. Therefore 5J(CH3,SH) is now dominated by a σ−π electron mechanism and is positive. Probably by coincidence, 4J(H,SH) in this compound is equal in magnitude but opposite in sign to 5J(CH3,SH).

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.

Synthese und Konformationsstudien ringsubstituierter Titanocen-Dithiolen-Chelate / Synthesis and Conform ational Studies of Ring-Substituted Titanocene Dithiolene Chelates

1986 ◽  
Vol 41 (6) ◽  
pp. 667-670 ◽  
Author(s):  
Hartmut Köpf ◽  
Thomas Klapötke
Keyword(s):  
Mass Spectra ◽  
Nmr Spectra ◽  
Chelating Ligands ◽  
Temperature Dependent ◽  
H Nmr ◽  
Fragmentation Processes

Abstract The titanocene dithiolenato chelates Cp′2Ti(S2C6H3CH3-4) and CpCp′Ti(S2C6H3CH3-4) (Cp = η5-C5H5, Cp′ = η5-C5H4CH3) were prepared by reaction o f Cp′2TiCl2 or CpCp′TiCl2 with equiva­lent amounts of 1,2 -(LiS)2C6H3CH3-4. The structure and the conform ational mobility of the η5-bonded and of the chelating ligands of the dithiolenato complexes are discussed on the basis of their temperature-dependent 1H NMR spectra. The mass spectra show metastable transitions for the fragmentation processes.

Restricted rotation about arene–oxygen bonds in some 1,3-di-tert-butyl-2-methoxyarenedicarbonylphosphorus(III)chromium compounds

1984 ◽  
Vol 62 (11) ◽  
pp. 2566-2569 ◽  
Author(s):  
Eva M. Campi ◽  
Bryan M. K. Gatehouse ◽  
W. Roy Jackson ◽  
Ian D. Rae ◽  
Margaret G. Wong
Keyword(s):  
Crystal Structure ◽  
Low Temperatures ◽  
Nmr Spectra ◽  
Hindered Rotation ◽  
Methyl Group ◽  
Tert Butyl ◽  
H Nmr ◽  
Free Energy Of Activation ◽  
Chromium Compounds ◽  
Related Compounds

The 1H nmr spectra of 1,3-di-tert-butyl-2-methoxybenzenedicarbonyltriphenylphosphinechromium (5) and some related compounds at low temperatures show the presence of two species which interconvert with free energy of activation near 50 kJ mol−1. The species differ in the orientation of the methoxy with respect to the chromium, since the same type of process is observed in a chelate complex in which a phosphinite ligand on chromium is also attached to the arene. Hindered rotation about the arene–chromium axis is not involved. The crystal structure of 5 shows the Ph3P anti to the methoxy and the O-methyl group proximal to chromium.

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