13C- und 15N-NMR-spektroskopische Untersuchungen einiger Pentacarbonylchrom-Aminophosphan-Komplexe/13C and 15N NMR Spectroscopic Study of Some Pentacarbonylchromium-Aminophosphane Complexes

1989 ◽  
Vol 44 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Klaus Schamei ◽  
Max Herberhold
Keyword(s):  
Binuclear Complex ◽  
Nmr Spectra ◽  
15N Nmr ◽  
Amino Groups ◽  
Nmr Parameters ◽  
Nmr Data ◽  
Regular Change ◽  
Nuclear Shielding ◽  
The Relationship ◽  
C Nmr

13C and 15N NMR data are reported for the free aminophosphanes ʹBu3-nP(NH2)n (n = 1 (1), 2 (2)), for the corresponding pentacarbonylchromium complexes (OC)5Cr-P(ʹBu)3-n(NH2)n (n = 1 (3), n = 2 (4), n = 3 (5)), and for other (OC)5Cr-aminophosphane complexes such as (OC)5Cr-P(NMe2)3, (6 ) and a binuclear complex (7) in which the sulfurdiimide derivative ʹBu(NH2)P-NSN-P(NH2)ʹBu serves as the phosphane ligand. Various techniques (e.g. INEPT and reverse two-dimensional (2D) 1H {15N}-experiments) have been used for recarding the 15N NMR spectra at natural abundance. In contrast to suggestions in the literature, the relationship between the 13C NMR parameters for the axial and equatorial CO groups and the σ-donor/π-acceptor properties of the phosphane ligand is not straightforward. The 15N resonances of the (OC)5Cr complexes 3, 4, 6 are shifted to higher frequencies with respect to those of the free ligands, and there is a regular decrease in 15N nuclear shielding in the series of 3, 4, 5. The |1J(31P15N)| values vary between 17 and 65 Hz, the smaller values being observed for the (OC)5Cr complexes. The lack of a regular change in the magnitude of 1J(31P15N) in the series 3, 4, 5 indicates that this parameter is influenced by the nature of both the Cr-P and the P-N bonds as a function of the number of amino groups.

Remarkably Large 15N, 13C and 18O Isotope NMR Shifts of the Mono-coordinate Phosphorus Atoms in the Compounds (Me3 Si)iPrNCP, K+[iPrNCP]-and KOCP · 2 DME (DME = 1,2-Dimethoxyethane)

2001 ◽  
Vol 56 (2) ◽  
pp. 146-151 ◽  
Author(s):  
Gemot Heckmann ◽  
Gerd Becker ◽  
Stephen Homer ◽  
Herbert Richard ◽  
Hans Kraft ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
Isotope Effects ◽  
Coupling Constants ◽  
Isotope Shifts ◽  
Nmr Data ◽  
Nuclear Shielding ◽  
18O Isotope ◽  
Geminal Coupling ◽  
O Isotope ◽  
C Nmr

The 31P and 13C NMR spectra of the heteroatom-substituted λ3-phosphaalkynes (Me3Si)- iPrNCP (1), K+ [iPrNCPl- (2) and KOCP · 2 DME (3) are described (Me = methyl; iPr = isopropyl). In addition,15N NMR data of 1 and 2 as well as further NMR results of all accessible nuclei of 1 to 3 are reported. The absolute values of the coupling constants 1J(31P13C) of 1, 2 and 3, 18.2, 45.7 and 57.2 Hz, respectively, are considerably different; the geminal coupling constants 2J( 31P15N) of the first two compounds show a decrease in the reverse order, 15.1 and 3.3 Hz. 13C, 29Si,15N, and 18O isotope effects on the nuclear shielding of the 31P nucleus in the non isotope-enriched compounds 1, 2 or 3 are presented and discussed. The [mono-13C]isotopomers of 1, 2 and 3 exhibit extremely negative 31P13C one-bond isotope shifts varying from -211 to -223 ppb. Remarkably, for 1 and 2 large two-bond 31P15N isotope shifts of -32 and -84 ppb, respectively, are observed. An unexpectedly large two-bond 31P180 isotope effect of -124 ppb was assigned to the [mono-180]isotopomer of compound 3. A three-bond 31P13C isotope shift of -27 ppb was found in 2.

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.

Anwendung der 15N-NMR-Spektroskopie zur Charakterisierung reaktiver, koordinativ ungesättigter Zinn-, Bleiund Phosphor-Stickstoff-Verbindungen / Application of 15N-NMR Spectroscopy to the Characterization of Reactive, Coordinatively Unsaturated Tin-, Lead- and Phosphorus-Nitrogen Compounds

1987 ◽  
Vol 42 (12) ◽  
pp. 1515-1519 ◽  
Author(s):  
Carin Stader ◽  
Bernd Wrackmeyer
Keyword(s):  
Nmr Spectra ◽  
Pulse Sequence ◽  
Coupling Constants ◽  
Spin Coupling ◽  
15N Nmr ◽  
Nmr Data ◽  
15N Nmr Spectroscopy ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

AbstractThe basic INEPT pulse sequence proved most useful for recording 15N NMR spectra at natural abundance of bis(amino)stannvlenes (1). -plumbylenes (2) and of imino-amino-λ2-phosphanes (3), where the nitrogen atoms carry bulky substituents like Me3Si-, t-Bu-, 2.4.4-trimethyl-2- pentyl-groups (t-Oct-groups) or are part of the 2.2.6.6-tetramethylpiperidinyl group. The sensitiv­ity of this technique is proved by the observation of 117/119Sn or 207Pb satellites owing to spin-spin coupling constants 1J(117/119Sn15N) and 1J(117/119Pb15N), respectively. NMR data of bis[bis(trimethylsilyl)methyl]tin (4) are reported in order to corroborate the arguments for the interpretation of the δ(15N) and 1J(119Sn15N) data. The 15N NMR data of the λ2-phosphanes (3) indicate a bonding situation similar to that in triazenes.

Electrophilic Substitution Reactions of [1]Benzothieno[3,2-b]furan

1996 ◽  
Vol 61 (6) ◽  
pp. 888-900 ◽  
Author(s):  
Jiří Svoboda ◽  
Pavel Pihera ◽  
Petr Sedmera ◽  
Jaroslav Paleček
Keyword(s):  
Electrophilic Substitution ◽  
Nmr Spectra ◽  
Substituent Effects ◽  
Substitution Reactions ◽  
Nmr Parameters ◽  
Elimination Mechanism ◽  
Electrophilic Substitution Reactions ◽  
C Nmr

In chlorination, bromination, iodination, nitration, sulfonation, formylation, and trifluoroacetylation of [1]benzothieno[3,2-b]furan (1) the substituent enters the 2-position. The said halogenations go by the addition-elimination mechanism. When the substitution is continued, the second substituent enters the 6-position of heterocycle 1. The 1H and 13C NMR spectra have been completely assigned. Substituent effects on NMR parameters are discussed.

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.

Anwendungen der 2 D-NMR-Spektroskopie in der Organophosphorchemie Beispiel: L-Menthyldichlorphosphan / Applications of the 2D NMR Spectroscopy in the Organophosphorus Chemistry Example: L-Menthyldichlorophosphine

1982 ◽  
Vol 37 (12) ◽  
pp. 1661-1664 ◽  
Author(s):  
Martin Feigel ◽  
Gerhard Hägele ◽  
Axel Hinke ◽  
Gudrun Tossing
Keyword(s):  
Nmr Spectroscopy ◽  
2D Nmr ◽  
2D Nmr Spectroscopy ◽  
H Nmr ◽  
Nmr Parameters ◽  
Nmr Data ◽  
Organophosphorus Chemistry ◽  
C Nmr

2D NMR ist used to determine the 1H NMR parameters of L-Menthyldichlorophosphine. 13C NMR data are given

13C-NMR chemische Verschiebung phenylsubstituierter polycyclischer Kohlenwasserstoffe / 13C-NMR Chemical Shift of Phenylsubstituted Polycyclic Hydrocarbons

1979 ◽  
Vol 34 (11) ◽  
pp. 1334-1343 ◽  
Author(s):  
W. Storek ◽  
J. Sauer ◽  
R. Stößer
Keyword(s):  
Chemical Shift ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Ring Current ◽  
Current Effect ◽  
Nmr Data ◽  
Ring Current Effect ◽  
Anisotropic Contribution ◽  
Chemische Verschiebung ◽  
C Nmr

13C-NMR spectra of tetracene, rubrene, 1,3,5-tri-, penta-, and hexaphenylbenzene are reported. The discussion also includes the already known 13C-NMR data for diphenyl, 9,10-diphenyl-, 9,10-dibenzyl-, and 9,10-dimethyl-anthracene [1] as well as toluene. On the basis of CNDO/2 calculations different influences (diamagnetic and paramagnetic term, anisotropic contribution, ring current effect, geometry) on the chemical shift are analyzed for diphenyl and within the row benzene through tetracene

13 C NMR Spectra of Chromeno-and Prenylated Flavones Structure Revision of Mulberrin, Mulberrochromene, Cyclomulberrin and Cyclomulberrochromene

1978 ◽  
Vol 33 (12) ◽  
pp. 1547-1549 ◽  
Author(s):  
V. Mohan Chari ◽  
Saboor Ahmad ◽  
Bengt-Göran Österdahl
Keyword(s):  
Nmr Spectra ◽  
Nmr Data ◽  
Structure Revision ◽  
Prenylated Flavones ◽  
C Nmr

AbstractReappraisal of the 13C NMR data for mulberrin and mulberrochromene indicate a revision of structure for these two compounds as well as for cyclomulberrin and cyclo-mulberrochromene .

Mercury(I) chemistry. Part II. Reactions of the mercurous ion with some ligands having the heavier Group VA or VIA elements as donor atoms

1976 ◽  
Vol 54 (1) ◽  
pp. 177-187 ◽  
Author(s):  
Philip A. W. Dean ◽  
David G. Ibbott
Keyword(s):  
Sulfur Dioxide ◽  
Nmr Spectra ◽  
Large Magnitude ◽  
Liquid Sulfur ◽  
H Nmr ◽  
Phosphine Complexes ◽  
Back Bonding ◽  
The Relationship ◽  
Mercurous Ion ◽  
C Nmr

The reactions of Hg2(AsF6)2 with P(CF3)3, PF3, PCl3, P(CF3)Ph2, PClPh2, PPh3, P(OMe)3, AsPh3, SbPh3, SPPh3, SP(p-C6H4F)3, and SePPh3 in liquid sulfur dioxide have been studied. The last five ligands form insoluble 1:1 complexes, Hg2(AsF6)2•L, if L:Hg22+ ≤ 1, but disproportionation of the mercurous ion occurs if L:Hg22+ > 1; the 1:1 mercurous complexes have been characterized by analysis and vibrational spectroscopy. There is no evidence for complexation of P(CF3)3. PPh3 and P(OMe)3 cause disproportionation of the mercurous ion under all conditions; Hg(PPh3)22+ and Hg(P(OMe)3)22+ have been characterized by 13C and 1H nmr respectively. When P(CF3)Ph2:Hg22+ ≤ 1 soluble Hg2(P(CF3)Ph2)2+ is formed; the 19F and 13C nmr spectra of this complex are reported, as are those of Hg(P(CF3)Ph2)22+. In the system PF3–Hg2(AsF6)2–SO2 no disproportionation occurs; 19F nmr provides evidence that Hg2PF32+ and, probably, Hg2(PF3)22+ are formed. 1J(P–F) in mercurous and silver(I) complexes of PF3 is of unusually large magnitude. The 13C nmr spectra of Hg(PPh3)22+, Hg2(P(CF3)PPh2)2+, and Hg(P(CF3)Ph2)22+, are consistent with the occurrence of little metal-to-phosphorus back-bonding in these phosphine complexes. The relationship between the net electron donating ability of a phosphine and the nature of its interaction with the mercurous ion is discussed.

NMR-spektroskopische Untersuchung des Problems der Valenzisomerie zwischen 1,2-Dithiin und (Z)-But-2-en-1,4-dithion / NMR Spectroscopic Investigation Concerning the Problem of Valence Isomerism between 1,2-Dithiine and (Z)-But-2-ene-1,4-dithione

1988 ◽  
Vol 43 (5) ◽  
pp. 605-610 ◽  
Author(s):  
Reiner Radeglia ◽  
Helmut Poleschner ◽  
Werner Schroth
Keyword(s):  
Nmr Spectra ◽  
Chemical Shifts ◽  
2D Nmr ◽  
Ring Structure ◽  
Coupling Constants ◽  
Nmr Parameters ◽  
Spectrum Simulation ◽  
2D Nmr Spectra ◽  
Transoid Conformation ◽  
C Nmr

3,6-Diaryl-1,2-dithiines and their precursors, (Z,Z)-1,4-bis(organylthio)-buta-1,3-dienes, are investigated by 1H and 13C NMR spectroscopy. The chemical shifts and coupling constants, which are relevant to the investigated problem, are determined and assigned, respectively, by different techniques (shift increments, spectrum simulation, heteronuclear 2D J-resolved and heteronuclear shift correlated 2D NMR spectra, anomalous off-resonance splittings and selective decoupling experiments). The NMR parameters are discussed in relation to the molecular structure. The 13C shift values prove the ring structure of 1,2-dithiines and exclude existence of the valence isomer (Z)-but-2-ene-1,4-dithione (absence of thiocarbonyl resonances). The vicinal 1H,1H coupling constants of the C4 unit of the investigated compounds verify (1) the (Z,Z) configuration of the organylthio groups in 1,4 position of butadiene, (2) the s-transoid conformation of acyclic butadienes and (3) the forced s-cis structure in the cyclic 1,2-dithiines.

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