263. Delocalization and magnetic properties of the phosphonitrilic halides

Craig, D. P.; Heffernan, ML; Mason, R. F.; Paddock, N. L.

doi:10.1039/jr9610001376

Cited by 18 publications

(20 citation statements)

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“…On the other hand, the average susceptibilities used for the calculations of K|, Table II, are For the benzene ring the value of ΔK' has been considered both theoretically and experimentally. The theoretical value as calculated by Edward and McWeeny is -37.8 [5] which is in agreement with the value of -38.00 given by Craig [19]. The experimental value is -38.20 [23].…”

Section: Resultssupporting

confidence: 79%

“…One can investigate the effect of the hydrogen bonding on the magnetic properties of the molecule by comparing the delocalization anisotropy of the molecule (ΔK') with that of the benzene ring. According to Mason [12] and Craig [19] the hydrogen bond can give rise to electron delocalization resulting in magnetic anisotropy. The delocalization anisotropy ΔK' is given by The values of the atomic susceptibilities used for the calculation of Σ Xatomic are: XC = -7.40 [12], ΧH = -2.00 [12], XO = -4.60 [20], XBr = -27.80 [17], and ΧN = -7.30 [14].…”

Section: Resultsmentioning

confidence: 99%

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Anisotropy of the Diamagnetic Susceptibility in 3,5-dibromo-p-amino and 3,5-dibromo-p-hydroxybenzoic Acids

Abdel‐Kader

1992

Acta Phys. Pol. A

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The mean molar susceptibility (X M ) for the two compounds 3,5-dibromo--p-aminobenzoic acid, Br2 C6 H2 (p-ΝH2)COOΗ, and 3,5-dibromo-p-hydroxybenzoic acid, Br2C6H2(p-OH)COOH, has been determined. The principal molecular susceptibilities K || and K 1 have been evaluated. The magnetic anisotropy of each of the two compounds was obtained. From the atonic coordinates, as given by the X-ray structure analysis of Br2C6H2(p-ΝH2)COOH, the crystal susceptibilities (Χ α , Xb, and X c ) have been calculated. The magnetic properties are interpreted in the light of the crystal structure. PACS numbers: 35.20.My In troductionThe strong anisotropy of the diamagnetic susceptibility of benzenoid compounds is usually explained in terms of ring current [1][2][3][4][5][6][7][8][9]. An interesting discussion with the use of ring current concept has been given by Gomes [10].In general, the principal molecular susceptibilities (K ┴ and K||) can be evaluated from the crystal susceptibilities (X1 , X2 , and χ3) combined with the orienta [9]. On the other hand, the diamagnetic anisotropy ΔK of the molecule can be calculated from the measured value of the molar susceptibility χM according to the relation [11]: where K|| is the in-plane susceptibility wlose value can be determined from the sum of the atomic susceptibilities of the molecule as discussed by Hoarau [ΙΙ] -t i o n o f t h e m o l e c u l e i n t h e c r y s t a l . T h e d e t a i l s o f t h i s m e t h o d w a s g i v e n e l s e w h e r e

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Section: Resultssupporting

confidence: 79%

Section: Resultsmentioning

confidence: 99%

Anisotropy of the Diamagnetic Susceptibility in 3,5-dibromo-p-amino and 3,5-dibromo-p-hydroxybenzoic Acids

Abdel‐Kader

1992

Acta Phys. Pol. A

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“…

The principal molecular susceptibilities of bisdehydro [14]annulene, determined from measurement of the diamagnetic anisotropy of a single crystal, are -20, -24 and -358 (• The results are in agreement with a London calculation of the ~r-electron contribution to the molecular anisotropy.

…”

supporting

confidence: 75%

“…In [18]annulene, the bond alternation scheme invoked by several authors [6][7][8][9] to explain the electronic spectrum was found to be incorrect, the observed bond lengths having a different pattern from those predicted by theoretical studies (see also [10]). By contrast, the r.m.s, deviation between observed and calculated bond lengths in 1,8 bisdehydro [14]annulene is better than 0.01 ~,.…”

Section: Introductionmentioning

confidence: 67%

“…The bond lengths in [18]annulene [2,3] and 1,8 bisdehydro [14]annulene [4,5] have been determined accurately by x-ray diffraction methods. In [18]annulene, the bond alternation scheme invoked by several authors [6][7][8][9] to explain the electronic spectrum was found to be incorrect, the observed bond lengths having a different pattern from those predicted by theoretical studies (see also [10]).…”

Section: Introductionmentioning

confidence: 99%

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