| Autor: |
Głowacki, Zdzisław, Hoffmann, Maria, Topolski, Marek, Rachon, Janusz |
| Zdroj: |
Phosphorus, Sulfur, and Silicon and the Related Elements; June 1991, Vol. 60 Issue: 1 p67-71, 5p |
| Abstrakt: |
31P chemical shifts are reported for twenty aminoalkylphosphonic acids (APAs), nine 1-hydroxyalkyl phosphonic (HPAs) and six phosphonic acids (PAs). The protonation shifts and the substituent-induced effects (SCSs) of the amino and hydroxyl groups on the 31P NMR and α-carbon 13C NMR chemical shifts were calculated and discussed. Substituent shielding effects on phosphorus nucleus and deshielding effects on α-carbon are observed for both groups. Amino shielding effect on phosphorus nucleus is the sum of two interactions: 1) electron-withdrawing substituent effect propagated along the carbon chain, 2) hydrogen bonding and coulombic attaction between groups in the zwitterion forms. Both imply the increasing contribution of a P=O resonance structure leading to the upfield S(P). Good linear correlation exist between chemical shifts of 1-hydroxyalkylphosphonic acids and the respective values of analogously constituted 1-aminoalkylphosphonic acids. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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