Reassignment of the structure of M3(CO)12(Cl)(SnCl3) (M = Ru, Os)

1989 ◽  
Vol 67 (7) ◽  
pp. 1236-1238 ◽  
Author(s):  
Anna Becalska ◽  
Roland K. Pomeroy ◽  
William A.G. Graham
Keyword(s):  
Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Room Temperature ◽  
Quantitative Yield ◽  
Nmr Spectrum ◽  
C Nmr

Reaction of M3(CO)12 (M=Ru, Os) with SnCl4 in benzene at room temperature affords M3(CO)12(Cl)(SnCl3) in essentially quantitative yield. The 13C nmr spectra of these complexes indicate they have a ClM3(SnCl3) arrangement of atoms with the Cl ligand cis and the SnCl3 group trans to a linear Os3 chain. This is contrary to previously proposed structures for these compounds. The 13C nmr spectrum of Os3(CO)12(I)2 which has the iodo ligands cis to the Os3 chain is also reported for comparison. Keywords: ruthenium–tin, osmium–tin, osmium–iodine, l3C nmr spectroscopy.

The Preparation of Some Mono-and Bis(thiolate)-2-butyne Complexes of Tungsten(II) of the Types [WI(SR)(CO)(dppm )(η2-MeC2Me)] {dppm = Ph2P(CH2)PPh2; R = Et, But, Ph or CH2Ph} and [W (SR)2(CO)(dppm)(η2-MeC2Me)]

1994 ◽  
Vol 49 (11) ◽  
pp. 1544-1548 ◽  
Author(s):  
Paul K. Baker ◽  
Kevin R. Flower
Keyword(s):  
Nmr Spectroscopy ◽  
Elemental Analysis ◽  
Good Yield ◽  
Nmr Spectra ◽  
Room Temperature ◽  
H Nmr ◽  
Thiolate Complexes ◽  
C Nmr

Equimolar quantities of [WI(CO)(NCMe)(dppm)(η2-MeC2Me)][BF4] {dppm = Ph2P(CH2)PPh2) and NaSR (R = Et. But ,Ph or CH2Ph) react in CH2Cl2 at room temperature to give the neutral thiolate complexes [WI(SR)(CO)(dppm)(η2-MeC2Me)] (1 → 4) in good yield. The complex [WI(CO)(NCMe)(dppm)(η2-MeC2Me)][BF4] also reacts with two equiv­alents of NaSR (R = Et. But, Ph or CH2Ph) in CH2Cl2 at room temperature to afford the bis(thiolate) complexes [W(SR)2(CO)(dppm)(η2-MeC2Me)] (5 → 8), in good yield. Com­plexes 1→8 have been characterized by elemental analysis (C, H and N), IR and 1H NMR spectroscopy. 13C NMR spectra of selected complexes indicate that the 2-butyne ligand is donating four electrons to the metal in both [WI(SR)(CO)(dppm)(η2-MeC2Me)] and [W(SR)2(CO)(dppm)(η2-MeC2Me)] type complexes.

Structural studies of digitoxin and related cardenolides by two-dimensional NMR

1990 ◽  
Vol 68 (2) ◽  
pp. 272-277 ◽  
Author(s):  
Torbjörn Drakenberg ◽  
Peter Brodelius ◽  
Deane D. McIntyre ◽  
Hans J Vogel
Keyword(s):  
Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Chair Conformation ◽  
Coupling Constants ◽  
Two Dimensional ◽  
Structural Studies ◽  
Solution Conformation ◽  
Phase Sensitive ◽  
Multiple Relay ◽  
C Nmr

The 1H and 13C NMR spectra of the cardenolides digitoxigenin, digoxigenin, digitoxin, and mono- and bis-digitoxigenin digitoxosides have been completely assigned by two-dimensional NMR spectroscopy. The techniques used include phase-sensitive COSY, multiple relay COSY, and carbon–proton correlation (HETCOR and HMQC) spectra. Various aspects of the solution conformation of the steroid moiety of digitoxin and digoxigenin could be determined from coupling constants and NOE difference experiments and they are indicative of an all-chair conformation. The carbohydrate rings in digitoxin and the mono- and bis-digitoxigenin digitoxosides are also in the chair conformation. Keywords: cardenolides, digitoxigenin, digitoxin, 2-dimensional NMR, conformational analysis.

Fusing Nickelocene and Cyclopentadiene by Two Silyl Bridges. Synthesis and 1H, 13C, and 29Si NMR Investigation of a Paramagnetic Building Block for High-Nuclear Metallocenes

1994 ◽  
Vol 49 (6) ◽  
pp. 763-769 ◽  
Author(s):  
Monika Fritz ◽  
Johann Hiermeier ◽  
Frank H. Köhler
Keyword(s):  
Building Block ◽  
Nmr Spectra ◽  
29Si Nmr ◽  
Nmr Spectrum ◽  
Anti Isomer ◽  
Bridging Ligand ◽  
Cyclopentadienyl Anion ◽  
C Nmr

Two isomers of tetrahydro-4,4,8,8-tetramethyl-4,8-disila-s-indacene (LH2) were monodeprotonated and treated with cyclopentadienyl anion and NiBr2(THF)1,5 to give a 72% yield of the mixed nickelocene CpNi(LH) where a cyclopentadiene is fused to a nickelocene. The analysis of the paramagnetic 1H, 13C, and 29Si NMR spectra demonstrated that the syn and anti isomer of CpNi(LH) formed in a ratio of 5/1. Both isomers could be deprotonated to yield the anion CpNi(L-). According to its 13C NMR spectrum the bridging ligand L is not planar

The Effect of Quinolyl Endgroups on Podand Fluctuations-1-DNMR and 2D-EXCSY-NMR of Co(II)-Complexes

1992 ◽  
Vol 47 (7) ◽  
pp. 911-914
Author(s):  
Franz L. Dickert ◽  
Matthias Feigl ◽  
Wolfgang Gmeiner ◽  
Harald U. Meißner
Keyword(s):  
Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Room Temperature ◽  
Ethylene Glycols ◽  
End Groups

Ligand fluctuations in complexes [Co(Kr5)]X2 (Kr 5 = 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane) with X = ClO4-, CF3SO3- can be detected by NMR spectroscopy above room temperature in inert solvents such as nitromethane. This unusually slow ligand movement is due to the strong coordination of the quinolyl end groups to the Co(II) ion as demonstrated through measurements with oligo-ethylene-glycols. In contrast to the 13C spectra, the 1H 2 D EXCSY NMR spectra reveal cross peaks which are due to a magnetisation exchange between the chemically non-equivalent protons in the -CH2- groups of the podand. This process is associated with a movement of the chain segments towards each other.

scholarly journals Synthesis and Single Crystal X-Ray Structure of Bis[4-oxo-3- (2-ethoxycarbonylphenyl)-3,4-dihydroquinazolin-2-yl]disulfide

2009 ◽  
Vol 64 (9) ◽  
pp. 1065-1069 ◽  
Author(s):  
Mehdi Rimaz ◽  
Jabbar Khalafy ◽  
Khadijeh Tavana ◽  
Katarzyna Ślepokura ◽  
Tadeusz Lis ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Single Crystal ◽  
Elemental Analysis ◽  
Structure Determination ◽  
Room Temperature ◽  
Sodium Ethoxide ◽  
Reaction Conditions ◽  
X Ray ◽  
Ethyl Nitroacetate ◽  
C Nmr

Diethyl 2,2´-thiocarbonyl-bis(azanediyl)dibenzoate was synthesized from the reaction of ethyl anthranilate with thiophosgene. Its treatment with sodium ethoxide in ethanol at room temperature gave ethyl 2-(4-oxo-2-thioxo-1,2-dihydroquinazolin-3(4H)-yl) benzoate, whereas in the presence of ethyl nitroacetate and under the same reaction conditions, the corresponding bis(quinazolin)disulfide was formed. Its structure was confirmed by IR, 1H and 13C NMR spectroscopy elemental analysis and single crystal X-ray structure determination.

Metall-π-Komplexe yon Benzolderivaten, XIII Bis(methylthio-η-beiizol)chrom(0) Darstellung und Einsatz als zweizähniger Chelatligand/ Metal-π Complexes of Benzene Derivatives, XIII Bis(methylthio-η-benzene)chromium(0) Preparation and Function as a Bidentate Chelating Ligand

1981 ◽  
Vol 36 (1) ◽  
pp. 94-101 ◽  
Author(s):  
Helmut Burdorf ◽  
Christoph Eischenbroich
Keyword(s):  
Nmr Spectra ◽  
Room Temperature ◽  
Radical Cations ◽  
Esr Spectra ◽  
Benzene Derivatives ◽  
Consecutive Reaction ◽  
H Nmr ◽  
Chelating Ligand ◽  
And Function ◽  
C Nmr

Abstract The thioanisole-π-complexes (methylthio-η-benzene)-(η-benzene)-chromium (2) and bis(methylthio-η-benzene)chromium (3) have been prepared via lithiation of bis(η-benzene)-chromium and consecutive reaction with dimethyldisulfide. 1H NMR and 13C NMR spectra of 2 and 3 as well as ESR-spectra of the corresponding radical cations 2.+ and 3.+ were recorded and analyzed. In contrast to C(η-arene)-Si and C(η-arene)-P bonds, C(y-arene)-S bonds are stable to solvolysis. With (norbornadiene)tetracarbonylmolybdenum, 3 readily forms [bis(methylthio-η-benzene)chromium]tetracarbonylmolybdenum (6) wherein 3 functions as a chelating ligand. 1H and 13C NMR evidence suggests, that at room temperature 6 undergoes rapid conformational interconversions.

1-Allylgermatrane. Synthesis, Structure and Reaction with Diazomethane

1997 ◽  
Vol 52 (1) ◽  
pp. 30-34 ◽  
Author(s):  
Galina S. Zaitseva ◽  
Sergey S. Karlov ◽  
Elena S. Alekseyeva ◽  
Leonid A. Aslanov ◽  
Evgeni V. Avtomonov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Nmr Spectroscopy ◽  
Structure Study ◽  
Quantitative Yield ◽  
High Yield ◽  
Crystalline Solid ◽  
Conformational Disorder ◽  
X Ray ◽  
C Nmr

Reaction of allyltribromogermane (2), readily available from dibromo(1,4-dioxane)germanium(II) (1) and allylbromide, with tris(2-tributylstannoxyethyl)-amine (4) gives 1-allylgermatrane (3) in almost quantitative yield. 3 crystallizes from n-pentane as a colourless crystalline solid which was characterized by 1H and 13C NMR spectroscopy and by an X-ray crystal structure study. The “atrane” skeleton shows a strong conformational disorder; the Ge-N distance of 2.208(3) Å suggests the presence of a coordinative Ge-N bond. Treatment of 1-allylgermatrane (3) with CH2N2 in the presence of catalytic amounts of Pd(OAc)2 affords 1-cyclopropylmethylgermatrane (5) in high yield

13C-Chemische Verschiebungen von Aminosäuren und Peptiden / 13C-NMR Chemical Shifts of Amino Acids and Peptides

1971 ◽  
Vol 26 (3) ◽  
pp. 213-222 ◽  
Author(s):  
Wolfgang Voelter ◽  
Günther Jung ◽  
Eberhard Breitmaier ◽  
Ernst Bayer
Keyword(s):  
Amino Acids ◽  
Fourier Transform ◽  
Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Analytical Tool ◽  
Reasonable Time ◽  
C Isotopes ◽  
Direct Recording ◽  
C Nmr

Pulse - Fourier - Transform-13C-NMR spectroscopy allowed the direct recording of 13C-NMR spectra of amino acids and peptides with natural abundance of 13C isotopes within a reasonable time. The 13C-signals of more than 50 free and protected amino acids and several peptides were assigned. 13C-NMR spectroscopy gives valuable information about the carbon skeleton, thus offering a new analytical tool for the study of biopolymers and their constituents.

Substituenteneinflüsse auf Synthese und Eigenschaften von Hexakis[phosphanaurio(I)]methanium(2+)bis(tetrafluoroboraten) / Substituent Effects in Synthesis and Properties of Hexakis[phosphineaurio(I)]methanium(2 +) Bis(tetrafluoroborates)

1992 ◽  
Vol 47 (12) ◽  
pp. 1725-1735 ◽  
Author(s):  
Hubert Schmidbaur ◽  
Benno Brachthäuser ◽  
Siegfried Gamper ◽  
Annette Schier ◽  
Oliver Steigelmann
Keyword(s):  
Nmr Spectra ◽  
Room Temperature ◽  
Substituent Effects ◽  
Reaction Times ◽  
Phosphine Ligands ◽  
Electronic Effects ◽  
X Ray ◽  
Magnetic Resonance Parameters ◽  
Interstitial Carbon Atom ◽  
C Nmr

Polyaurated carbon complexes of the type [(L–Au)6C]2+ with functionalized phosphine ligands have been prepared by the reaction of the phosphinegold(I) chlorides R(Ph)2PAuCl (R = p-C6H4-Cl 2a,p-C6H4-Br 2b,p-C6H4-CH3 2c,p-C6H4-OCH3 2d,p-C6H4-COOH 2e, p-C6H4–N(CH3)2 2f), R2(Ph)PAuCl (R = p-C6H4-N(CH3)2 2g) and R3PAuCl (R = p-C6H4-N(CH3)2 2h) with tetrakis(dimethoxyboryl)methane in HMPT at room temperature. Clearly depending on the different inductive and mesomeric effects, the preparation of the clusters with substituents like –CH3 3c, –OCH3 3d and –N(CH3)2 3f needs shorter reaction times and the products show better solubility in organic solvents than those with functional groups like –Cl 3a, –Br 3b and –COOH 3e. The 31P magnetic resonance parameters are correlated with electronic effects of the substituents, but the chemical shift of the interstitial carbon atom in the 13C-NMR spectra is largely independent of the coordinating ligands. For the phosphinegold(I) chlorides 2f–h X-ray structure analyses have been performed.

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