Preparation and Nuclear Magnetic Resonance Study of Phosphorus Compounds Containing Alkenyl Functional Groups

1974 ◽  
Vol 52 (9) ◽  
pp. 1714-1720 ◽  
Author(s):  
Peter W. Clark ◽  
John L. S. Curtis ◽  
Philip E. Garrou ◽  
George E. Hartwell
Keyword(s):  
Magnetic Resonance ◽  
Nuclear Magnetic Resonance Study ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Phosphorus Compounds ◽  
Proton Spectrum ◽  
Phosphine Oxides ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling ◽  
Proton Decoupling

The phosphines PPhn(CH2CH2CH=CH2)3−n, n = 2–0, PPhn(CH2CH2CH2CH=CH2)3−n, n = 1 or 2, and PPh2CH2CH = CH2 have been synthesized and studied by 1H and 31P magnetic resonance. The n.m.r. spectra of PPh2(OCH2CH=CH2), its oxide, O=PPh2(OCH2CH=CH2), and its Arbuzov rearrangement product, O=PPh2(CH2CH=CH2), have been investigated by 31P decoupling of the proton spectrum, selective proton decoupling of the 31P spectrum, and comparison with computer-simulated spectra to determine the spin–spin coupling constants. The n.m.r. spectra of the related oxides O=PPh2CH2CH2CH=CH2, O=P(CH2CH2CH=CH2)3, and O=P(OCH2CH=CH2)3 are also assigned. The data indicate that 3JPH > 2JPH for alkenylphosphines, 2JPH is larger for phosphine oxides than for phosphines, and 3JPH is little changed in comparing phosphorus(III) with phosphorus(V) compounds.

An estimate of the spin–spin coupling constant, 1J(1H,13C), in gaseous benzene

1996 ◽  
Vol 74 (8) ◽  
pp. 1524-1525 ◽  
Author(s):  
Ted Schaefer ◽  
Guy M. Bernard ◽  
Frank E. Hruska
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Dielectric Constant ◽  
Magnetic Resonance ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Coupling Constant ◽  
Spin Coupling Constant ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling ◽  
Gaseous Benzene

An excellent linear correlation (r = 0.9999) exists between the spin–spin coupling constants 1J(1H,13C), in benzene dissolved in four solvents (R. Laatikainen et al. J. Am. Chem. Soc. 117, 11006 (1995)) and Ando's solvation dielectric function, ε/(ε – 1). The solvents are cyclohexane, carbon disulfide, pyridine, and acetone. 1J(1H,13C)for gaseous benzene is predicted to be 156.99(2) Hz at 300 K. Key words: spin–spin coupling constants, 1J(1H,13C) for benzene in the vapor phase; spin–spin coupling constants, solvent dielectric constant dependence of 1J(1H,13C) in benzene; benzene, estimate of 1J(1H,13C) in the vapor; nuclear magnetic resonance, estimate of 1J(1H,13C) in gaseous benzene.

A proton magnetic resonance determination of the small rotational barriers about the C—Si bond in phenyl derivatives of chloro and methyl silanes

1977 ◽  
Vol 55 (3) ◽  
pp. 557-561 ◽  
Author(s):  
William J. E. Parr ◽  
Ted Schaefer
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Molecular Orbital Calculations ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling ◽  
Derivatives Of ◽  
Low Energy Conformations

The long-range spin–spin coupling constants between protons bonded to silicon and ring protons in C6H5SiH3, C6H5SiH2Cl, C6H5SiH2CH3, C6H5SiHCl2, and C6H5SiH(CH3)2 are determined from the proton magnetic resonance spectra of benzene solutions. A hindered rotor treatment of the barrier to internal rotation about the C—Si bond, in conjunction with the coupling constants over six bonds, allows the deduction of the low-energy conformations for C6H5SiH(CH3)2 and for C6H5SiHCl2, as well as of barriers of 1.0 ± 0.2 kcal/mol. The approach becomes less reliable for C6H5SiH2CH3 and for C6H5SiH2Cl and, particularly for the latter compound, the derived barrier is very likely an upper limit only. Ab initio molecular orbital calculations of the conformational energies are reported for C6H5SiH3, C6H5SiH2Cl, and for C6H5SiHCl2.

Proton and fluorine magnetic resonance studies of some benzoyl fluoride derivatives. Sensitivity of the fluorine shifts to intramolecular van der Waals interactions and steric effects

1977 ◽  
Vol 55 (22) ◽  
pp. 3936-3941 ◽  
Author(s):  
Ted Schaefer ◽  
Kirk Marat ◽  
Kalvin Chum ◽  
Alexander F. Janzen
Keyword(s):  
Magnetic Resonance ◽  
Van Der Waals ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Van Der Waals Interactions ◽  
Proton Proton ◽  
Out Of Plane ◽  
Spin Coupling Constants ◽  
The Individual ◽  
Spin Spin Coupling

The syntheses and the analyses of the high resolution proton and fluorine magnetic resonance spectra of the 3-fluoro-4-methyl-, 2-fluoro-5-chloro-, 2-fluoro-6-chloro-, 2,6-difluoro-, and of the pentafluorobenzoyl fluorides are reported. The spin–spin coupling constants over five bonds between the sidechain fluorine-19 and the ring protons are sensitive to intrinsic substituent perturbations. Their use in the deduction of conformational preferences is much more problematical than is the use of the corresponding proton–proton couplings in benzaldehyde derivatives. The 2-fluoro-6-chloro compound is nonplanar, as indicated by a finite magnitude of the long-range proton–fluorine coupling over six bonds. The nonplanarity is also indicated by a comparison of the through-space fluorine–fluorine coupling to those in the other compounds. The chemical shift of the sidechain fluorine moves to low field by over 35 ppm as the size of the two ortho substituents increases. The individual shifts are discussed in terms of intramolecular van der Waals interactions and of out-of-plane twisting of the COF group.

Nuclear Magnetic Resonance Spectra, Conformations, Spin Coupling Mechanisms, and INDO Molecular Orbital Calculations for the Monofluorobenzaldehydes and some Derivatives

1971 ◽  
Vol 49 (19) ◽  
pp. 3216-3228 ◽  
Author(s):  
R. Wasylishen ◽  
T. Schaefer
Keyword(s):  
Magnetic Resonance ◽  
Molecular Orbital ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Molecular Orbital Calculations ◽  
Conformational Preferences ◽  
Coupling Parameters ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling ◽  
Magnetic Resonance Spectra

Precise analyses of the proton and some fluorine magnetic resonance spectra in acetone solution are reported for the three monofluorobenzaldehydes as well as for 2-chloro-6-fluorobenzaldehyde and for 4-fluoro-2-nitrobenzaldehyde. The conformational dependence of the coupling parameters allows the measurement of energy differences between the O-cis and O-trans conformations. The energy differences are in better agreement with the INDO predictions than they are with energies derived from i.r. data. Di-pole moments are computed reliably and their measurement is suggested as a good guide to conformational preferences for molecules of this kind. The spin–spin coupling constants between the aldehyde proton and the ring protons and fluorine nuclei are computed for benzaldehyde and the three monofluorobenzaldehydes by the INDO and CNDO molecular orbital approximations. In many instances the agreement between calculated and observed couplings is quantitative.

Conformational dependence of long-range spin-spin coupling constants in 2,6-dichlorobenzylfluoride

1969 ◽  
Vol 47 (19) ◽  
pp. 3688-3690 ◽  
Author(s):  
T. Schaefer ◽  
C. M. Wong ◽  
K. C. Tam
Keyword(s):  
Magnetic Resonance ◽  
Long Range ◽  
Proton Magnetic Resonance ◽  
Resonance Spectrum ◽  
Double Resonance ◽  
Proton Magnetic Resonance Spectrum ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

Double resonance experiments on the proton magnetic resonance spectrum of 2,6-dichlorobenzylfluoride yield the signs of the long-range coupling constants between the ring protons and the fluorine nuclei and protons in the fluoromethyl group. The signs and magnitudes of the long-range couplings are discussed in terms of their dependence on the conformation of the fluoromethyl group.

Anisotropy of indirect spin–spin coupling constants from nuclear magnetic resonance powder patterns of rigid solids. 1J(31P,199Hg) in [HgP(o-tolyl)3(NO3)2]2

1988 ◽  
Vol 66 (8) ◽  
pp. 1821-1823 ◽  
Author(s):  
Glenn H. Penner ◽  
William P. Power ◽  
Roderick E. Wasylishen
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Coupling Constant ◽  
Spin Coupling Constants ◽  
Fermi Contact ◽  
Spin Spin Coupling ◽  
Contact Mechanism ◽  
Nuclear Magnetic

The anisotropy of the indirect 31P,199Hg spin–spin coupling constant, ΔJ, in solid [HgP(o-tolyl)3(NO3)2]2 is obtained from an analysis of the 31P nuclear magnetic resonance powder pattern. The value of ΔJ, 5170 ± 250 Hz, is large and indicates that mechanisms other than the Fermi contact mechanism are important for this spin–spin coupling. The powder spectrum also indicates that the absolute sign of 1J(31P,199Hg) is positive.

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