The additivity of NMR carbon–carbon spin–spin coupling constants

Marshall, James L.; Faehl, Larry G.; Kattner, Richard

doi:10.1002/mrc.1270120308

Cited by 43 publications

(12 citation statements)

References 33 publications

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“…[7] instead of 4 a. We have confirmed the nature o f 3 and 4 a by obtaining consistent 'H and 13C NM R spectroscopic data (see footnotes to Table I 4,5,6,7 and Fe3(CO)]2 and were purified by chromato graphy on silica which also served to retain para magnetic impurities. This method gave 4 and 7 as pure products whereas 5 and 6 were isolated as a 40:60 mixture.…”

Section: Chemical Shifts S19snsupporting

confidence: 54%

¹¹⁹Sn NMR Spectroscopy of Some Iron-Tin Compounds – First Measurements of One-Bond Coupling Constants ¹J(¹¹⁹Sn⁵⁷Fe), Geminal Coupling Constants ²J(¹¹⁹SnFe¹¹⁹Sn) and the Dependence of ¹¹⁹Sn Chemical Shifts on the Nature of the Sn–Fe Bond

Wrackmeyer

Distler

Herberhold

1992

Zeitschrift Für Naturforschung B

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Carbonyliron-Tin Complexes, 119Sn N M R , Coupling ConstantsCarbonyliron tin complexes CpFe(CO )2-S n M e 3 (1), a5-(CO)4Fe(SnM e3)2 (2), cis-(CO)4Fe(SnM e2Cl)2 (3), [R2SnFe(CO)4]2 (4a, R = Me; 4b, R = Bu), {Me2Sn[Fe(CO)4]2}2Sn (5), Me2Sn[Fe(CO)4]2Sn[Fe(CO)4]2 (6) and Sn[Fe(CO)4]4 (7) were studied by ll9Sn N M R . It proved possible for the first time to observe coupling constants './(119Sn57Fe) in the range of 36 to 64 Hz. The large magnitude of geminal coupling constants 12/ ( 119SnFell9Sn)| (1400 to 1800 Hz) in the cyclic com pounds 4 to 6 indicates the presence of tin-tin interactions as an efficient coupling pathway. Extreme deshielding o f 119Sn nuclei in the complexes 6 (<5u9Sn + 953) and 7 (<5119Sn + 1532) is associated with three-centre FeSnFe bonds in these compounds.Carbonyliron complexes containing F e -S n bonds are readily available by various synthetic methods [1], The reaction of Fe(CO)5 with organotin compounds appears to be particularly conven ient, since the product distribution depends criti cally on the reaction conditions. In the case of methyltin compounds, major products (4, 5, 7) which could be crystallized were finally character ized by X-ray analysis [2], Although these results appear to be conclusive, there is some doubt about the correct assessment of all major species present in the reaction solution. We have now repeated some of the reactions between organotin com pounds and Fe(CO)5 and have applied 119Sn NM R in order to get more information on the composi tion of the reaction solutions. Furthermore, we wanted to determine one-bond coupling constants '7(119Sn57Fe) and to compare the magnitude of geminal coupling constants 2/ ( 119Sn119Sn) across Fe in non-cyclic and cyclic compounds. For these purposes we have studied compounds 1 to 7. Results and DiscussionWith the exception of compounds 3 and 6, all complexes were prepared following known proce-* Reprint requests to Prof. Dr. Bernd Wrackmeyer.Verlag der Zeitschrift für Naturforschung, D-W -7400 Tübingen 0 9 3 2 -0 7 7 6 /9 2 /1 2 0 0 -1 7 4 9 /$ 01.00/0 Cp Fe(CO)2-SnMe3

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Section: Chemical Shifts S19snsupporting

confidence: 54%

¹¹⁹Sn NMR Spectroscopy of Some Iron-Tin Compounds – First Measurements of One-Bond Coupling Constants ¹J(¹¹⁹Sn⁵⁷Fe), Geminal Coupling Constants ²J(¹¹⁹SnFe¹¹⁹Sn) and the Dependence of ¹¹⁹Sn Chemical Shifts on the Nature of the Sn–Fe Bond

Wrackmeyer

Distler

Herberhold

1992

Zeitschrift Für Naturforschung B

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“…130 Evidently, the resultant of two simultaneous coupling pathways can be unexpectedly large, or anomalously small, as in the 3+3 J C-1–C-4 values of many aldohexopyranoses. 122 …”

Section: Vicinal Coupling Constantsmentioning

confidence: 99%

Chapter 3 Developments in the Karplus Equation as they Relate to the NMR Coupling Constants of Carbohydrates

Coxon

2009

Advances in Carbohydrate Chemistry and Biochemistry

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“…Athough a number of 3~(C,C) values have been reported for benzene derivatives in which one of the coupled nuclei resides in a side chain (41), few are available for the P-position. In acetophenone, ,3J(C,C) is 8.4 Hz for the 13C nucleus in the methyl group (42), whereas in phenylacetic acid 3 J ( C ,~) is 1.9 Hz for the I3C nucleus in the carboxyl group (43). The latter molecule has a large preference (44) for a conformation in which the carboxyl group lies in a plane perpendicular to that of the benzene ring.…”

Section: Indo Mo Fpt Computationsmentioning

confidence: 99%

Long-range ¹³C, ¹³C spin–spin coupling constants in anisole and some derivatives

Schaefer¹,

Penner²

1988

Can. J. Chem.

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13C nuclear magnetic resonance chemical shifts and nJ(13C,13C) are reported for anisole and 16 of its derivatives, all enriched with 13C in the methoxyl group. 5J(13C,13C) is directly proportional to sin2θ, where θ is the angle by which the methoxy group twists about the C(1)—O bond. In acetone-d6 solution, 5J(C,C) is not observable for a number of 4-substituted anisoles, except for 1,4-dimethoxybenzene. For the latter, 5J(C,C) is compatible with a twofold barrier of 19.3 ± 1.1 kJ/mol hindering rotation about the C(1)—O bond. However, it is unlikely that the barrier is purely twofold in nature. The observed 5J(C,C) is also compatible with 10.5 and 6.0 kJ/mol for the twofold and fourfold components, respectively, implying a dynamical nuclear magnetic resonance barrier of less than 13 kJ/mol. While phase and solvent effects on the internal barrier in anisole are certainly substantial, it appears that a fourfold component must also be present. The apparent twofold barrier in 2,6-difluoroanisole is 5.4 ± 0.9 kJ/mol, based on 5J(C,C) and 6J(H-4,13C). The latter coupling constant is also reported for 1,2,3-trimethoxybenzene and used to deduce its conformation. The θ dependence of 3J(C,C) and 4J(C,C) is briefly discussed for symmetrical anisole derivatives. Differential 13C, 13C isotope shifts are reported for 1,4-dimethoxybenzene.

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The additivity of NMR carbon–carbon spin–spin coupling constants

Cited by 43 publications

References 33 publications

¹¹⁹Sn NMR Spectroscopy of Some Iron-Tin Compounds – First Measurements of One-Bond Coupling Constants ¹J(¹¹⁹Sn⁵⁷Fe), Geminal Coupling Constants ²J(¹¹⁹SnFe¹¹⁹Sn) and the Dependence of ¹¹⁹Sn Chemical Shifts on the Nature of the Sn–Fe Bond

¹¹⁹Sn NMR Spectroscopy of Some Iron-Tin Compounds – First Measurements of One-Bond Coupling Constants ¹J(¹¹⁹Sn⁵⁷Fe), Geminal Coupling Constants ²J(¹¹⁹SnFe¹¹⁹Sn) and the Dependence of ¹¹⁹Sn Chemical Shifts on the Nature of the Sn–Fe Bond

Chapter 3 Developments in the Karplus Equation as they Relate to the NMR Coupling Constants of Carbohydrates

Long-range ¹³C, ¹³C spin–spin coupling constants in anisole and some derivatives

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The additivity of NMR carbon–carbon spin–spin coupling constants

Cited by 43 publications

References 33 publications

119Sn NMR Spectroscopy of Some Iron-Tin Compounds – First Measurements of One-Bond Coupling Constants 1J(119Sn57Fe), Geminal Coupling Constants 2J(119SnFe119Sn) and the Dependence of 119Sn Chemical Shifts on the Nature of the Sn–Fe Bond

119Sn NMR Spectroscopy of Some Iron-Tin Compounds – First Measurements of One-Bond Coupling Constants 1J(119Sn57Fe), Geminal Coupling Constants 2J(119SnFe119Sn) and the Dependence of 119Sn Chemical Shifts on the Nature of the Sn–Fe Bond

Chapter 3 Developments in the Karplus Equation as they Relate to the NMR Coupling Constants of Carbohydrates

Long-range 13C, 13C spin–spin coupling constants in anisole and some derivatives

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¹¹⁹Sn NMR Spectroscopy of Some Iron-Tin Compounds – First Measurements of One-Bond Coupling Constants ¹J(¹¹⁹Sn⁵⁷Fe), Geminal Coupling Constants ²J(¹¹⁹SnFe¹¹⁹Sn) and the Dependence of ¹¹⁹Sn Chemical Shifts on the Nature of the Sn–Fe Bond

¹¹⁹Sn NMR Spectroscopy of Some Iron-Tin Compounds – First Measurements of One-Bond Coupling Constants ¹J(¹¹⁹Sn⁵⁷Fe), Geminal Coupling Constants ²J(¹¹⁹SnFe¹¹⁹Sn) and the Dependence of ¹¹⁹Sn Chemical Shifts on the Nature of the Sn–Fe Bond

Long-range ¹³C, ¹³C spin–spin coupling constants in anisole and some derivatives