solutions. It is found that the nature of the substituent greatly affects the basicity of ligands for porphyrins characterized by a flat structure of macrocycle. The electronic effects of substituents have a much weaker influence on the kinetics of complexing. These effects could be due to the opposite orientation of some factors: an increase in the basicity and stability of the N–H bonds of porphyrin
在非
水溶液中分光光度法研究了烷基和芳基内消旋
卟啉的酸碱和配位性质。发现取代基的性质极大地影响了以大环的平坦结构为特征的
卟啉配体的碱性。取代基的电子效应对络合动力学的影响要弱得多。这些影响可能是由于某些因素的方向相反:
卟啉反应中心N–H键的碱性和稳定性增加。测量
卟啉的内消旋取代的衍
生物的阳离子形式的解离常数p K b。p K b的值 与取代基的性质的经典概念高度吻合,特别是那些通过苯基缓冲环间接包含在大环中的取代基。