极化率与Al−CH_(3)的δ(^(1)H),δ(^(13)C)的相关性研究  

Study on the correlation between polarizability andδ(^(1)H),δ(^(13)C)of Al−CH_(3)

作　　者：刘瑞元 丁玉强 LIU Rui-yuan;DING Yu-qiang(School of Chemical and Material Engineering,Jiangnan University,Wuxi 214122,Jiangsu,China)

机构地区：[1]江南大学化学与材料工程学院,江苏无锡214122

出　　处：《云南大学学报（自然科学版）》2022年第5期1018-1026,共9页Journal of Yunnan University(Natural Sciences Edition)

基　　金：江苏省研究生科研创新计划(博士)(KYCX18-1807)。

摘　　要：根据甲基铝配合物的Al−CH_(3)的^(1)H NMR[δ(^(1)H)],^(13)C NMR化学位移[δ(^(13)C)]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(σ_(m))和配体的Lever参数(E_(L))等3个参数的角度研究了烷基的极化率与Al−CH_(3)的δ(^(1)H)、δ(^(13)C)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−CH_(3)的δ(^(1)H)、δ(^(13)C)有良好相关性(吡咯-2-亚胺,R2>0.95),取代基对δ(^(1)H)的影响大于δ(^(13)C).在降低位阻的情况下,烷基的极化率与Al−CH_(3)的δ(^(1)H)、δ(^(13)C)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−CH_(3)的δ(^(1)H)、δ(^(13)C)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−CH_(3)的δ(^(1)H)也有良好的相关性(磷配体,β-二酮).极化率与Al−CH_(3)的δ(^(1)H)、δ(^(13)C)的相关性研究结果说明Al−CH_(3)的δ(^(1)H)、δ(^(13)C)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.According to the chemical shift of 1H NMR[δ(^(1)H)]and^(13)C NMR[δ(^(13)C)]of Al−CH_(3)of methyl-aluminum complex being easily affected by steric hindrance,induced effect(polarizability,σ_(α)),field-effect(σ_(F))and conjugation effect(σ_(R)),and the main substituent effect of alkyl mainly coming from steric hindrance and polarizability,the relationship between the polarizability of alkyl andδ(^(1)H),δ(^(13)C)of Al−CH_(3)was studied from the point of view of substituents'polarizability,Hammett parameters(σ_(m))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 withδ(^(1)H)andδ(^(13)C)of Al−CH_(3)(pyrrolylaldiminate,R2>0.95),and the effect of substituents onδ(^(1)H)is greater than that ofδ(^(13)C).In the case of limiting the steric hindrance of substituents,the polarizability of alkyl has a good correlation withδ(^(1)H)andδ(^(13)C)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 onδ(^(1)H),δ(^(13)C)of Al−CH_(3)(phosphorus ligand).When substituents'steric hindrance and polarizability are limited,the Hammett parameters(σ_(m))of substituents and Lever parameters(EL)of ligands are also well correlated withδ(^(1)H)of Al−CH_(3)(phosphorus ligands,β-diketones).The study on correlation between polarizability andδ(^(1)H),δ(^(13)C)of Al−CH_(3)is suggested thatδ(^(1)H)andδ(^(13)C)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.

关 键 词：核磁共振 极化率 甲基铝配合物 配体 取代基效应 

分 类 号：O614.3[理学—无机化学]