刘瑞元, 丁玉强. 极化率与Al−CH3δ(1H),δ(13C)的相关性研究[J]. 云南大学学报(自然科学版), 2022, 44(5): 1018-1026. doi: 10.7540/j.ynu.20210620
引用本文: 刘瑞元, 丁玉强. 极化率与Al−CH3δ(1H),δ(13C)的相关性研究[J]. 云南大学学报(自然科学版), 2022, 44(5): 1018-1026. doi: 10.7540/j.ynu.20210620
LIU Rui-yuan, DING Yu-qiang. Study on the correlation between polarizability and δ(1H), δ(13C) of Al−CH3[J]. Journal of Yunnan University: Natural Sciences Edition, 2022, 44(5): 1018-1026. DOI: 10.7540/j.ynu.20210620
Citation: LIU Rui-yuan, DING Yu-qiang. Study on the correlation between polarizability and δ(1H), δ(13C) of Al−CH3[J]. Journal of Yunnan University: Natural Sciences Edition, 2022, 44(5): 1018-1026. DOI: 10.7540/j.ynu.20210620

极化率与Al−CH3δ(1H),δ(13C)的相关性研究

Study on the correlation between polarizability and δ(1H), δ(13C) of Al−CH3

  • 摘要: 根据甲基铝配合物的Al−CH31H NMRδ(1H),13C NMR化学位移δ(13C)易受到取代基的位阻、诱导效应(极化率)、场效应和共轭效应影响的特征,以及烷基的主要取代基效应主要来自于位阻和极化率,从取代基极化率、取代基Hammett参数(σm)和配体的Lever参数(EL)等3个参数的角度研究了烷基的极化率与Al−CH3δ(1H)、δ(13C)的关系. 研究发现,在降低取代基位阻的情况下,烷基的极化率与Al−CH3δ(1H)、δ(13C)有良好相关性(吡咯-2-亚胺, R2>0.95),取代基对δ(1H)的影响大于δ(13C). 在降低位阻的情况下,烷基的极化率与Al−CH3δ(1H)、δ(13C)有良好相关性的规律适用多个配体(吡咯-2-亚胺,醇,β-二亚胺,R2>0.95);取代基的共轭效应、场效应会缓解极化率对Al−CH3δ(1H)、δ(13C)的影响(磷配体);降低取代基的位阻和极化率,取代基Hammett参数和配体的Lever参数与Al−CH3δ(1H)也有良好的相关性(磷配体,β-二酮). 极化率与Al−CH3δ(1H)、δ(13C)的相关性研究结果说明Al−CH3δ(1H)、δ(13C)对取代基效应有良好的响应性,具有应用于研究取代基效应对配体影响的潜力.

     

    Abstract: According to the chemical shift of 1H NMRδ(1H) and 13C NMRδ(13C) of Al−CH3 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−CH3 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−CH3 (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−CH3. 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−CH3 (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−CH3 (phosphorus ligands, β-diketones). The study on correlation between polarizability and δ(1H), δ(13C) of Al−CH3 is suggested that δ (1H) and δ (13C) of Al−CH3 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.

     

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