Abstract:
According to the chemical shift of
1H NMR
δ(
1H) and
13C NMR
δ(
13C) of Al−CH
3 of methyl-aluminum complex being easily affected by steric hindrance, induced effect (polarizability,
σα), field-effect (
σF) and conjugation effect (
σR), and the main substituent effect of alkyl mainly coming from steric hindrance and polarizability, the relationship between the polarizability of alkyl and
δ(
1H),
δ(
13C) of Al−CH
3 was studied from the point of view of substituents' polarizability, Hammett parameters (
σm) and Lever parameters (
EL) of ligands. It is found that when the steric hindrance of substituents is limited, the polarizability of alkyl has a good correlation with
δ (
1H) and
δ (
13C) of Al−CH
3 (pyrrolylaldiminate,
R2>0.95), and the effect of substituents on
δ(
1H) is greater than that of
δ(
13C). In the case of limiting the steric hindrance of substituents, the polarizability of alkyl has a good correlation with δ(
1H) and
δ(
13C) of Al−CH
3. It is suitable for multiple ligands (pyrrolylaldiminate, alcohol,
β-diimine,
R2>0.95). The conjugation effect of substituents and the field-effect should alleviate the effect of polarizability on
δ(
1H),
δ(
13C) of Al−CH
3 (phosphorus ligand). When substituents' steric hindrance and polarizability are limited, the Hammett parameters (
σm) of substituents and Lever parameters (
EL) of ligands are also well correlated with
δ (
1H) of Al−CH
3 (phosphorus ligands,
β-diketones). The study on correlation between polarizability and
δ(
1H),
δ(
13C) of Al−CH
3 is suggested that
δ (
1H) and
δ (
13C) of Al−CH
3 can respond to the change of substituent effect, and it has the potential to be used to study the effect of substituent effect on the ligand.