Four diverse meso-tetraarylporphyrins in the form of diprotonated adducts with trifluoro-, trichloro-, tribromoacetic acids and acetic acid were investigated in benzene solution. Despite similar structural distortion of the chromophore system due to protonation, the respective adducts demonstrated different photostability when exposed to UV irradiation. The trifluoro- and trichloroacetic adducts, and the acetic acid one, showed some common features both molecular and in the mechanism of photodegradation. However, the tribromo-derivative decayed according to a different kinetic scheme, revealing a considerable impact of the bromine atoms upon the pyrrole units of the porphyrin macrocycle, which led to extremely low UV resistance. Singlet molecular oxygen generated by the studied species was confirmed to contribute to the photolysis of the porphyrin system.

四种多样的中观在苯溶液中研究了具有三氟乙酸，三氯乙酸，三溴乙酸和乙酸的双质子化加合物形式的四芳基卟啉。尽管由于质子化导致生色团系统发生类似的结构变形，但当暴露于UV辐射下时，相应的加合物仍显示出不同的光稳定性。三氟和三氯乙酸加合物以及乙酸之一，在分子和光降解机理上均表现出一些共同的特征。然而，三溴衍生物根据不同的动力学方案衰变，表明溴原子对卟啉大环的吡咯单元有相当大的影响，这导致极低的抗紫外线性。研究物种产生的单重态分子氧被证实有助于卟啉系统的光解。