Reassignment of the1H NMR spectrum of fusidic acid and total assignment of1H and13C NMR spectra of some selected fusidane derivatives

2002 ◽  
Vol 40 (7) ◽  
pp. 471-473 ◽  
Author(s):  
Niels Rastrup-Andersen ◽  
Tore Duvold
Keyword(s):  
Fusidic Acid ◽  
Nmr Spectra ◽  
Nmr Spectrum

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.

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

Das 7,8-Benzo-5-chloro-1,4,4-trimethyl-1-aza-4-azonia-6,9-dioxa-5 λ5-phosphaspiro[4.4]nonanyl-Kation: Röntgenstrukturanalyse und temperaturabhängige 1H-NMR-Spektren: The 7, 8-Benzo-5-chloro-1,4,4-trimethyl-1-aza-4-azonia-6,9-dioxa-5 λ).5-phosphaspiro[4.4]nonanyl Cation: X-Ray Crystal Structure Determination and Variable 1H NMR Spectra

1992 ◽  
Vol 47 (6) ◽  
pp. 755-759 ◽  
Author(s):  
Thomas Kaukorat ◽  
Peter G. Jones ◽  
Reinhard Schmutzler
Keyword(s):  
Crystal Structure ◽  
1H Nmr ◽  
Nmr Spectra ◽  
Crystal Structure Analysis ◽  
Acceptor Interaction ◽  
Nmr Spectrum ◽  
X Ray ◽  
H Nmr ◽  
Trigonal Bipyramidal ◽  
Donor Acceptor

The 1H NMR spectrum of the spirophosphorane 3 at room temperature indicates dynamic behaviour of the cation. The low-temperature 1H NMR spectra of 3 exhibit two sets of doublets for the protons of the diastereotopic N(CH3)2 groups. The free enthalpy of activation for the dynamic process was determined (58.6 KJ/mole). In the reaction of 3 with sodium tetraphenylborate the crystalline compound, 4, involving the non-coordinating anion, [B(C6H5)4]-, was obtained. The X-ray crystal structure analysis of 4 reveals the presence of a five-membered ring, formally as a result of intramolecular donor-acceptor interaction between the nitrogen atom of the N(CH3)2 group and phosphorus. The geometry at phosphorus deviates somewhat from ideal trigonal bipyramidal.

Darstellung, 11B-und 19F-NMR-Spektren des Monofluoropentaiodo- closo-hexaboratanions sowie Kristallstruktur von (CH2Py2)[B6FI5]/ Synthesis, 11B and 19F NMR Spectra of the Monofluoropentaiodo-closo-hexaborate Anion and the Crystal Structure of (CH2Py2)[B6FI5]

1998 ◽  
Vol 53 (8) ◽  
pp. 829-832 ◽  
Author(s):  
H. Thomsen ◽  
W. Preetz
Keyword(s):  
Crystal Structure ◽  
Nmr Spectra ◽  
19F Nmr ◽  
Coupling Constant ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
19F Nmr Spectra ◽  
Nmr Spectrum ◽  
X Ray ◽  
Excess Iodine

Abstract By reaction of closo-[B6H5F]2- in alkaline solution with excess iodine the monofluoropentaiodo- closo-hexaborate anion [B6FI5]2- is formed in good yield. The crystal structure of (CH2Py2)[B6FI5] has been determined by single crystal X-ray diffraction analysis (orthorhombic, space group Pnma, a = 13.803(2), b = 11.759(2), c = 13.936(2) Å, Z = 4). The B-F-bond length is 1.41 Å, the B-I distances range from 2.13 to 2.17 Å, the B-B distances from 1.69 to 1.76 A. According to the C4v point symmetry the 11B NMR spectrum of the anion exhibits three singlets at +3.8,-30.1 and-33.3 ppm with the intensity ratio 1:4:1, the 19F NMR spectrum one quartet at -247.6 ppm with the coupling constant 1J (19F, 11B) = 54 Hz.

scholarly journals Anisotropy in RFe2 Intermetallics: An NMR Study

2009 ◽  
Vol 14 ◽  
pp. 71
Author(s):  
C Carboni
Keyword(s):  
Rare Earth ◽  
Hyperfine Interaction ◽  
Crystal Field ◽  
Field Dependence ◽  
Nmr Spectra ◽  
Rare Earth Ions ◽  
Nmr Spectrum ◽  
Nmr Study ◽  
Binary Compounds

The anisotropy of the Ho3+, Tb3+ and Tm3+ rare-earth ions in RFe2 compounds is investigated using the field dependence of the NMR spectra of 169Tm, 159Tb and 165Ho in polycrystalline TmFe2, TbFe2, HoFe2 and related pseudo-binary compounds. The very large hyperfine interaction in these ions dominates the NMR spectrum; the NMR frequencies in the 2 to 7 GHz range provide therefore a measure of the localized  moment and its orientation in the crystal field. We compare the NMR measurements to single ion computations that include magnetostriction. KEYWORDS:  

scholarly journals NMR-TS: De Novo Molecule Identification from NMR Spectra

2020 ◽  
Author(s):  
Jinzhe Zhang ◽  
Kei Terayama ◽  
Masato Sumita ◽  
Kazuki Yoshizoe ◽  
Kengo Ito ◽  
...  
Keyword(s):  
Density Functional ◽  
Nmr Spectra ◽  
De Novo ◽  
Expert Knowledge ◽  
Chemical Space ◽  
Automated Identification ◽  
Functional Theory ◽  
Nmr Spectrum ◽  
Chemical Structures ◽  
Target Spectrum

<div>NMR spectroscopy is an effective tool for identifying molecules in a sample. Although many previously observed NMR spectra are accumulated in public databases, they cover only a tiny fraction of the chemical space, and molecule identification is typically accomplished manually based on expert knowledge. Herein, we propose NMR-TS, a machine-learning-based python library, to automatically identify any molecule from its NMR spectrum. NMR-TS discovers candidate molecules whose NMR spectra match the target spectrum by using deep learning and density functional theory (DFT)-computed spectra. As a proof-of-concept, we identify prototypical metabolites from their computed spectra. After an average 5451 DFT runs for each spectrum, six of the nine molecules are identified correctly, and proximal molecules are obtained in the other cases. This encouraging result implies that de novo molecule generation can contribute to the fully automated identification of chemical structures. NMR-TS is available at https://github.com/tsudalab/NMR-TS. <br></div>

29Si, 13C and 31P NMR spectra of silicon-substituted ω-diphenylphosphinoalkyl silanes, (CH3)3-n(OC2H5)nSi(CH2)mP(C6H5)2

1982 ◽  
Vol 47 (3) ◽  
pp. 793-801 ◽  
Author(s):  
Jan Schraml ◽  
Martin Čapka ◽  
Harald Jancke
Keyword(s):  
Nmr Spectra ◽  
31P Nmr ◽  
Chemical Shifts ◽  
Additivity Rule ◽  
Ethoxy Group ◽  
Spectral Parameters ◽  
Nmr Spectrum ◽  
Nmr Parameters ◽  
13C And 31P Nmr ◽  
C Nmr

29Si, 13C, and 31P NMR spectra of a series of compounds of the structure (CH3)3-n(C2H5O)n.Si(CH2)mP(C6H5)2 (m = 1-6, n = )-3) are reported and assigned. Using monodeutero derivative of the compound with m = 3 and n = 0 an earlier assignment of 13C NMR spectrum is confirmed, but the assignment in the compounds with m = 4 is reversed. Introduction of ethoxy groups leads to violation of additivity rule for the 13C chemical shifts in the derivatives with m = 1. In all derivatives presence of one ethoxy group in the molecule has a profound effect on 31P chemical shift which is not changed by any further increase in the number of ethoxy groups in the molecule. The changes in 29Si chemical shifts follow the pattern known from other series of compounds. The observed trends in NMR parameters with changing n and m values can be explained by an interaction between phosphorus and oxygen atoms. Possible connections between the spectral parameters and catalysis employing the studied compounds are discussed.

1H NMR Spectrum: A Team-Based Tabletop Game for Molecular Structure Elucidation

2020 ◽  
Author(s):  
Zachary Thammavongsy ◽  
Michael A. Morris ◽  
Renee Link
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
1H Nmr Spectra ◽  
Molecular Formula ◽  
College Level ◽  
Nmr Spectrum ◽  
Laboratory Course

The 1H NMR Spectrum game, the first example of a team-based tabletop game focused on elucidating the structures of organic small molecules using 1H NMR spectra, was developed and deployed in a college level organic chemistry lecture course and laboratory course. The tabletop game was designed as a collaborative and competitive group activity to encourage multiple rounds of play to help students reinforce their 1H NMR spectra interpretation skills. While playing in either team-based or free-for-all mode, students analyzed the provided chemical shifts, splitting patterns, integrations, and molecular formula within a designated time limit to correctly deduce the structure associated with the 1H NMR spectrum. After playing the game, students in a lecture course and a laboratory course self-reported that they felt more comfortable solving 1H NMR spectroscopy questions, found the game to be an appealing study aid, and were able to complete multiple rounds of play to strengthen their skills in interpreting 1H NMR spectra. The 1H NMR Spectrum tabletop game may serve as an engaging and competitive group learning tool to supplement teaching on 1H NMR spectroscopy.

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