Carbon-boron coupling constants

The section on Spectroscopy has been retained but with some revisions and expansion. The section includes ultraviolet-visible spectroscopy, fluorescence, infrared and Raman spectroscopy, and X-ray spectrometry. Detection limits are listed for the elements when using flame emission, flame atomic absorption, electrothermal atomic absorption, argon induction coupled plasma, and flame atomic fluorescence. Nuclear magnetic resonance embraces tables for the nuclear properties of the elements, proton chemical shifts and coupling constants, and similar material for carbon-13, boron-11, nitrogen-15, fluorine-19, silicon-19, and phosphoms-31. 

Proton NMR shifts have been interpreted in terms of a ring current, and some coupling constants also indicate aromatic properties. Boron-11 shifts alone can apparently not be used as criteria of aromaticity, in the same way that carbon-13 shifts are not meaningful. 

Table 2 Isotropic hyperfine coupling constant for the ground states of the boron atom (2PU), carbon atom (3Pg) and nitrogen atom (4S U), using different levels of the Cl treatment. NO s were used as one-particle basis.

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