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Hammett方程一般适用于对位或间位取代的芳香系化合物。前文曾报道N-(对位或间位取代苯基)氨基乙酸的铜(Ⅱ)、镍(Ⅱ)及锌(Ⅱ)配合物的稳定性与配位体酸碱强度之间存在直线自由能关系,符合一般规律。但邻位取代效应使Hammett方程常常不能适用,主要是在不同的反应体系中,取代基与反应中心有不同程度的相互作用。然而,当邻位取代基并不明显地存在电子效应外的其它效应时,也可观察到符合Hammett方程的直线自由能关系。本文研究了N-(邻位取代苯基)氨基乙酸配合物体系的直线自由能关系。用pH法在0.10 M高氯酸钠存在下25℃测定了N-o-RPhNHOH_2COOH(R=CH_3O,
The Hammett equation generally applies to para-substituted or meta-substituted aromatic compounds. It has been previously reported that there exists a linear free energy between the stability of copper (II), nickel (II) and zinc (II) complexes of N- (para or meta substituted phenyl) glycine and the ligand acid- Relationship, in line with the general law. However, the ortho-substitution effect often makes the Hammett equation not applicable, mainly in different reaction systems, the substituents have different degrees of interaction with the reaction center. However, when the ortho substituent does not obviously have any other effect than the electron effect, the linear free energy relationship according to the Hammett equation can also be observed. In this paper, the relationship between the linear free energy of the system of N- (ortho-substituted phenyl) aminoacetic acid complex was studied. N-o-RPhNHOH 2 COOH (R = CH 3 O, Na 2 COOH) was measured by the pH method in the presence of 0.10 M sodium perchlorate