Shielding-density functions interpret nuclear magnetic shieldings point-wise, through the Biot–Savart law. For aromatic, antiaromatic, and non-aromatic p-systems (benzene, cyclooctatetraene, borazine), the characteristic pattern of current density leads to a distinctive map for the p-contribution to the perpendicular components of 1H shielding-density. Hence, global and localised currents have distinguishable signatures, dependent on separation between outward and return circulations in the current–density map. Aromatic, diatropic p-current produces an intense deshielding ipso spike, weakly cancelled by a remote shielding ridge; paratropic anti-aromatic p-current inverts these features; localised p-currents produce cancelling shielding/deshielding spikes. Ringcurrents also contribute characteristically to out-of-plane carbon shieldings.
Titolo: | Ring-current signatures in shielding-density maps |
Autori: | |
Data di pubblicazione: | 2005 |
Rivista: | |
Abstract: | Shielding-density functions interpret nuclear magnetic shieldings point-wise, through the Biot–Savart law. For aromatic, antiaromatic, and non-aromatic p-systems (benzene, cyclooctatetraene, borazine), the characteristic pattern of current density leads to a distinctive map for the p-contribution to the perpendicular components of 1H shielding-density. Hence, global and localised currents have distinguishable signatures, dependent on separation between outward and return circulations in the current–density map. Aromatic, diatropic p-current produces an intense deshielding ipso spike, weakly cancelled by a remote shielding ridge; paratropic anti-aromatic p-current inverts these features; localised p-currents produce cancelling shielding/deshielding spikes. Ringcurrents also contribute characteristically to out-of-plane carbon shieldings. |
Handle: | http://hdl.handle.net/11386/1058338 |
Appare nelle tipologie: | 1.1.2 Articolo su rivista con ISSN |