Ab initio magnetic shielding tensors of malonaldehyde

Abstract The magnetic shielding tensors of the hydroxyl proton and the carbon atoms are reported for the enolic form of malonaldehyde, β-hydroxyacrolein. The gauge invariance of the basis set is examined by the use of the Arrighini—Maestro—Moccia tensors. Good invariance is found for the carbon atoms. The shielding tensors are broken down into orbital contributions, and it is seen that there is very little π circulation to account for the downfield shift of the enolic proton.