Theory of the anisotropic diamagnetic susceptibility of aromatic compounds caused by ring currents, with allowance for ?-electron interaction

1972 ◽  
Vol 5 (6) ◽  
pp. 539-543
Author(s):  
L. I. Egorova ◽  
L. A. Borovinskii
Keyword(s):  
Aromatic Compounds ◽  
Diamagnetic Susceptibility ◽  
Electron Interaction ◽  
Ring Currents

Existence of ring currents in cyclic conjugated molecules and their contribution to the diamagnetic susceptibility

1971 ◽  
Vol 12 (3) ◽  
pp. 507-508 ◽  
Author(s):  
M. D. Kumanova ◽  
T. K. Rebane
Keyword(s):  
Diamagnetic Susceptibility ◽  
Conjugated Molecules ◽  
Ring Currents

The anisotropy of the g -factor for polycyclic hydrocarbons

1964 ◽  
Vol 278 (1372) ◽  
pp. 129-136 ◽  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Chemical Shift ◽  
Diamagnetic Susceptibility ◽  
Paramagnetic Species ◽  
Polycyclic Hydrocarbon ◽  
Molecular Orbital Theory ◽  
Orbital Theory ◽  
Ring Currents ◽  
Self Consistent

An external magnetic field acting on a polycyclic hydrocarbon induces ring currents of mobile electrons in its various rings. This effect can be observed in a diamagnetic molecule by means of the large anisotropies of diamagnetic susceptibility and chemical shift which are produced. For paramagnetic species these observations are no longer available and it is suggested that the anisotropy of the electronic g -factor should be used instead. This arises because the secondary magnetic field of the ring currents helps to orient the electron spins. In the Hamiltonian it is the spin-other-orbit term which produces this interaction. The magnitude of this term is calculated for various species using the unrestricted molecular orbital theory in its self-consistent form and A g zz is of the order 3 x 10 -5.

scholarly journals Diamagnetic anisotropy of organic molecules

1939 ◽  
Vol 171 (947) ◽  
pp. 541-568 ◽  
Keyword(s):  
Fatty Acids ◽  
Refractive Index ◽  
Aromatic Compounds ◽  
Organic Molecule ◽  
Organic Molecules ◽  
Diamagnetic Susceptibility ◽  
Positive Sign ◽  
Magnetic Birefringence ◽  
Unsaturated Alcohols ◽  
Diamagnetic Anisotropy

The large positive value of the magnetic birefringence (Cotton-Mouton effect) of aromatic compounds led (Raman and Krishnan 1927) to the deduction, subsequently verified, that these compounds must possess pronounced molecular diamagnetic anisotropy, in addition to their already well-known optical anisotropy. The sign of the magnetic birefringence is very significant (Bhagavantam 1929). The positive sign indicates that, for uniaxial or approximately uniaxial molecules, the direction of maximum diamagnetic susceptibility is one of minimum optical polarizability, that is, of least refractive index. This is strikingly true of aromatic compounds, but must also be true of other classes of compound which show positive magnetic birefringence, such as ketones, fatty acids, esters of fatty acids and unsaturated alcohols. Very little information is as yet available concerning the magnetic anisotropy of these classes of organic molecule, measurements having been confined almost entirely to the aromatic compounds.

The preparation of thiophenes. III. From aromatic compounds and carbon disulphide

1981 ◽  
Vol 31 (1) ◽  
pp. 163-166 ◽  
Author(s):  
Farid Azizian ◽  
James S. Pizey
Keyword(s):  
Aromatic Compounds ◽  
Carbon Disulphide

Bromination of some aromatic compounds by means of bromine in tetrachloroethane medium

1974 ◽  
Vol 24 (1-2) ◽  
pp. 59-61 ◽  
Author(s):  
A. I. Hashem
Keyword(s):  
Aromatic Compounds

1679 Fatty acid profile, sensory traits, and aromatic compounds of chops from lambs fed ground woody plants as roughage in feedlot finishing diets

2016 ◽  
Vol 94 (suppl_5) ◽  
pp. 818-818
Author(s):  
K. R. Wall ◽  
C. R. Kerth ◽  
T. R. Whitney ◽  
S. B. Smith ◽  
J. L. Glasscock ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Profile ◽  
Aromatic Compounds ◽  
Woody Plants ◽  
Finishing Diets

Tandem Mass Spectrometric Evaluation of Core Structures of Aromatic Compounds after Catalytic Deoxygenation

2017 ◽  
Author(s):  
Xueming Dong
Keyword(s):  
Aromatic Compounds ◽  
Supported Catalyst ◽  
Mass Spectrometric ◽  
Spectrometric Method ◽  
Mass Spectrometric Method ◽  
Aromatic Rings ◽  
Tandem Mass Spectrometric ◽  
Catalytic Deoxygenation ◽  
Oxygen Atoms

Catalytic deoxygenation of coal enhances the stability and combustion performance of coal-derived liquids. However, determination of the selectivity of removal of oxygen atoms incorporated in or residing outside of aromatic rings is challenging. This limits the ability to evaluate the success of catalytic deoxygenation processes. A mass spectrometric method, in-source collision-activated dissociation (ISCAD), combined with high resolution product ion detection, is demonstrated to allow the determination of whether the oxygen atoms in aromatic compounds reside outside of aromatic rings or are part of the aromatic system, because alkyl chains can be removed from aromatic cores via ISCAD. Application of this method for the analysis of a subbituminous coal treated using a supported catalyst revealed that the catalytic treatment reduced the number of oxygen-containing heteroaromatic rings but not the number of oxygen atoms residing outside the aromatic rings.<br>

Tandem Mass Spectrometric Evaluation of Core Structures of Aromatic Compounds after Catalytic Deoxygenation

2017 ◽  
Author(s):  
Xueming Dong
Keyword(s):  
Aromatic Compounds ◽  
Supported Catalyst ◽  
Mass Spectrometric ◽  
Spectrometric Method ◽  
Mass Spectrometric Method ◽  
Aromatic Rings ◽  
Tandem Mass Spectrometric ◽  
Catalytic Deoxygenation ◽  
Oxygen Atoms

Catalytic deoxygenation of coal enhances the stability and combustion performance of coal-derived liquids. However, determination of the selectivity of removal of oxygen atoms incorporated in or residing outside of aromatic rings is challenging. This limits the ability to evaluate the success of catalytic deoxygenation processes. A mass spectrometric method, in-source collision-activated dissociation (ISCAD), combined with high resolution product ion detection, is demonstrated to allow the determination of whether the oxygen atoms in aromatic compounds reside outside of aromatic rings or are part of the aromatic system, because alkyl chains can be removed from aromatic cores via ISCAD. Application of this method for the analysis of a subbituminous coal treated using a supported catalyst revealed that the catalytic treatment reduced the number of oxygen-containing heteroaromatic rings but not the number of oxygen atoms residing outside the aromatic rings.<br>

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