Thermal stability of boron subphthalocyanines as a function of the axial and peripheral substitution

In this work, we have carried out the synthesis and thermogravimetric study of 10 different axially and peripherally substituted boron subphthalocyanines, in order to compare their thermal stabilities under non-oxidizing conditions. We demonstrate that, in general, these compounds enjoy a relatively high thermal stability, a property that is fundamental for future potential applications. The loss of the axial group is usually the first thermal degradation process to occur, and the temperature at which it takes place increases as a function of the nature of this substituent in the order: Br < OH ⩽ OPh ∼ Cl. Peripheral substituents also have an influence on the thermal properties of subphthalocyanines, though their role is somewhat less notable.