冠醚配合物热力学性质的研究(Ⅶ)-碱金属与2,3-苯并-6-甲基-15-冠-5配位反应的量热滴定研究

Studies on Thermodynamics of Crown Coordination Compounds(Ⅷ)-Calorimitric Titration for Coordination Reaction of 2,3-Benzo-6-Methyl-15-Crown-5 with Alkali Metal Ions

用自制跟踪绝热式滴定量热计研究了新合成的2,3-苯并-6-甲基-15-冠-5在无水甲醇介质中与碱金属的配位反应。

The coordination reaction of 2,3-bcnzo-6-methyl-15-crown-5(BCl-15C5)with alkali metal ions was studied in anhydrous methanol by using homemade titr-ation calorimeter of follow-up adiabatic type.The calculated results show that,except the 1:1 coordination compounds,potassium forms 1:2 coordination compounds,but sodium and rubidium do not,and cesium does not react with the crown at all because of its big radius.When methyl was added to crown ring of benzo-15-crown-5,both the stability and coordination reaction enthalpy of 1:1 coordination compounds decreased.This implies that the effect of space hindrance of methyl is stronger than that of increasing electron density on oxygen atom of crown ring.This resembles the effect of methyl to be added to crown ring of benzo-18-crown-6 on coordination reaction studied by us previously.