Journal of Organometallic Chemistry ( IF 2.1 ) Pub Date : 2020-08-02 , DOI: 10.1016/j.jorganchem.2020.121464 Saeedeh Saadati , Milad Esfandiar
A series of β-brominated meso-tetraphenylporphyrins, H2TPPBrx (x = 0, 4, 8) have been synthesized and the photocatalytic activity of their manganese (III) and nickel (II) complexes in photo oxidation of styrene was thoroughly investigated. The green photo oxidation process was done using molecular oxygen and in the presence of visible light. The effect of solvent and bromination degree was studied on the catalytic activity and stability of sensitizers. Based on the obtained results, free base porphyrins showed better catalytic activity among metallated counterparts and the order of catalytic activity was as follows: H2TPPBr4>H2TPPBr8>H2TPP. The order for Ni and Mn metallated porphyrins was also obtained as: NiTPPBr8>NiTPPBr4>NiTPP and MnTPPBr4(OAc)>MnTPP(OAc)⋙MnTPPBr8(OAc), respectively. According to the stability studies, significant increase was observed after addition of metal in porphyrin structure; i.e. more than 80% in the case of Ni. Finally, a mechanism was proposed for photo oxidation of styrene in the presence of H2TPP porphyrin.
中文翻译:
的部分和完全β-溴化内消旋对苯乙烯的光氧化锰和镍配合物的在分子氧和可见光的存在的催化活性的影响:-tetraphenylporphyrin
合成了一系列β-溴的内消旋四苯基卟啉,H 2 TPPBr x(x = 0,4,8 ),并全面研究了其锰(III)和镍(II)配合物在苯乙烯光氧化中的光催化活性。 。在可见光的存在下,使用分子氧完成了绿色光氧化过程。研究了溶剂和溴化度对敏化剂催化活性和稳定性的影响。根据所得结果,游离碱卟啉在金属化对应物中显示出更好的催化活性,并且催化活性的顺序为:H 2 TPPBr 4 > H 2 TPPBr 8> H 2 TPP。镍和锰金属卟啉的顺序也分别为:NiTPPBr 8 > NiTPPBr 4 > NiTPP和MnTPPBr 4(OAc)> MnTPP(OAc)→MnTPPBr 8(OAc)。根据稳定性研究,在卟啉结构中添加金属后观察到显着增加。即在镍的情况下大于80%。最后,提出了在H 2 TPP卟啉存在下苯乙烯光氧化的机理。